Model Engine Maker

Engines => From Plans => Topic started by: tinglett on December 28, 2014, 03:36:23 PM

Title: Pottymill horizontal engine build
Post by: tinglett on December 28, 2014, 03:36:23 PM
Here's another start for a beginner build.  This will be my fourth engine and my first non-oscillator so I'm pretty excited.  I'll post more detail than most on this board need to see in the hopes that it helps other beginners, but keep in mind I'm no expert and hopefully others will chime in with alternative ways of doing things.

Update:  The prints are in metric for this engine, but I built it in imperial.  I posted notes here http://www.modelenginemaker.com/index.php/topic,4919.msg94957.html#msg94957 for those who want to do the same.

This is a horizontal mill engine designed by Stewart Hart who kindly sent updated plans to me a couple months ago.  He designed it as a beginner engine.  The prints I am using are Binder1V3.pdf for future reference.  Stew created a thread in Plans & Drawings for this almost two years ago (http://www.modelenginemaker.com/index.php?topic=1388.0) but beware that anything you find over there is a bit out of date.   Here is a rendering from that thread:

(http://www.modelenginemaker.com/index.php?action=dlattach;topic=1388.0;attach=3634;image)

Again, thanks to Stew, and I hope I don't embarrass him too much with my stumbling through this :).  BTW, I have both a lathe and mill (7x12 Harbor Freight lathe and LMS 3990 HiTorque X2 mini mill) as well as a bunch of new tools I'd like to try out on this engine.  That means some of my setups will be overkill, but I need to learn how to use all this stuff sometime.  And finally, I'd better mention that Stew's prints are metric and my hobby shop is setup for imperial.  I can measure metric easy enough with digital calipers, but my tooling is imperial (mainly drill bits and taps) and my stock also starts as imperial.  I decided that in general I'll stick to metric, but I'll need to do some adaptation along the way.  Hopefully I won't mess up anything critical doing this.

I decided to start with the cylinder.  It's easy enough and I know I can turn a piston to fit the cylinder much easier than the other way around.  The cylinder is a generic design for use with multiple engines.  Here it what it looks like, but for this engine it will have a second flat.  The first flat as shown is for mounting the slide valve, and the extra flat at 90 degrees is for a mounting block for attaching it to the base.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap1_zps81268e02.png)

I first faced a length of 1 3/8" aluminum rod.  This is nearly exactly 35mm which will be the size of the cylinder covers.  I could have used 1 1/4" which is just a bit under 32mm, but I didn't have any in the shop...so I decided to turn the rod to exactly 32mm.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_102546_zpss2bhj7l0.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_105853_zps7tdyuxvu.jpg)

Here I am starting to drill the 16mm opening, which is slightly over 5/8".  I had original intended to flip the part end-for-end and cut the cylinder covers before doing this.  At my skill level I've learned it is very hard to do this and keep the hole perfectly centered, but with the cylinder this wouldn't matter.  However, the blank turned out to be a bit short, so I decided to drill it in place and use another part to make the cylinder covers.  You'll see that in the next post.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_121234_zps6mbexjlw.jpg)

My largest drill and reamer are 1/2" so I had to bore this one.  This was a new operation for me as I just got a new AXA toolpost for my lathe.  Yes, it's monster-big on this thing, but so far it's working very well.  The boring tools I had are too small so I had to spend a little time to make them fit.  It seemed to work well.  My 4-jaw is pretty big so it all matches :).  NOTE:  why am I using a 4-jaw chuck?  It was already on the lathe and I was too lazy to change it...and besides I needed practice centering.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_135356_zpsut434a3v.jpg)

I turned it around using soda can to protect it.  I indicated it again, even though this was really unnecessary since I'm only parting it off.  Extra practice.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_1424352_zpsnlnfx9uq.jpg)

I faced it for good measure.  This brought the length down to 44mm (well, actually 43.87mm, but that was close enough for this).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_142708_zpssi0yclzk.jpg)

Next it went into the mill to make the flat.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_161029_zps21hrqpxy.jpg)

And finally I rotated it to make the other flat.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_173844_zps6mvupozc.jpg)

Stew's instructions say the cylinder can be made without a mill.  I was tempted to try making it from square stock just to see if I could get the math right.  The plan shows the flat area as 29.86mm vs the overall diameter of 32mm.  I think I could have chosen an edge and moved it out 13.86mm, rather than actually centered at 16mm, and turned it down to 32mm to get the same effect.

Next I need to drill the intake/exhaust passages and make the covers I mentioned earlier.  I think I'll wait with the bolt pattern for the slide valve and drill the parts together.  I don't have a DRO so it would be difficult for me to do them individually and expect them to line up.  I plan to do the same for the cylinder covers, too.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on December 28, 2014, 03:42:41 PM
Nice start and excellent pictures Todd...I'll be looking forward to following along on your build of this one.

Bill

Edit: Todd, I see Binder1 in the thread you noted but not a V3 version.
Title: Re: Pottymill horizontal engine build
Post by: Johnmcc69 on December 28, 2014, 05:19:04 PM
A very nice start....Stew has made some really great drawings & designs & offers them free. My hat's off to him for offering all his talent & all the other members here who have done so.

 You're doing a fine job Todd, nice pix & you have obviously put some time into thinking through your setups. You'll have this built with no problems.

 Keep the updates coming, it's going to be a beautiful engine.  :)

 John
Title: Re: Pottymill horizontal engine build
Post by: tinglett on December 28, 2014, 08:58:21 PM
Bill,

I got Binder1V3.pdf direct from Stew.  I'm sure he's made updates, though I haven't studied both sets close enough to see what changed.  For a general overview, Binder1.pdf over in that thread is good enough to see what you are getting into, but I believe Stew is attempting to keep it updated.

Todd
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on December 28, 2014, 09:37:18 PM
Hi Chaps

Thanks for your interest in my little engine, there have been quite a few made, the design is quite robust to the odd mistake and inaccuracy.

Nice start on the cylinder Todd  :ThumbsUp: for some reason I always like to make the cylinder of engine first.

Binder1v3 is the up to date version of the drawing, as I said there have been quite a few engines made to these drawing so they should be mistake free but if any of you guys spot any errors just let me know and I'll correct them and up date the version.

Cheers

Stew
Title: Re: Pottymill horizontal engine build
Post by: tinglett on December 28, 2014, 09:40:17 PM
Another update.  I've been getting good time in the shop! :)

Next, I decided to make the intake/exhaust ports.  I figure it would be easy to mess this up and I'd rather get it over before going to all the work of attaching matching covers and slide valve.

From the diagram in my previous post you can see these are routed from the center of a side on the flat to the outer edge where they sneak into the cylinder.  I decided to start with the two ports on the side which go half way through the cylinder wall.  I calculated this at about 0.100"

To locate these ports I used the edge finder on the movable jaw of the vise.  I knew the cylinder is 32mm diameter and I didn't want to calculate offsets from the flat.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_173844_zps6mvupozc.jpg)

I dialed the mill into the centerline at 16mm (0.630"), locked the Y, and then located in to drill the ports.  Note that I have a DI setup to measure depth.  My mill has a micro depth control, but it's not trustworthy.  I use the microadjust to move the head, and use the DI to know how far I've really gone.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_174901_zpsfudqubeq.jpg)

These ports are 4mm.  I decided that a #21 bit was the closest match and made a note in my notebook so I'd make them all that way.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_175703_zpsmgpwn5ku.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_180530_zps3tjm41je.jpg)

Now I flipped the cylinder on edge.  The flat that was against the fixed jaw is still there, and my Y is locked, so everything should line up.  Here I'm finding the edge again.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_181838_zpspzcgjfxc.jpg)

Then I dialed in to the center of the cylinder wall.  If you are *real* observant, you might see that I started drilling and then moved back to the left slightly.  The hole was uncomfortably close to the inside wall so I brought it back 0.020".  Here is where I realized there is either a discrepancy in the prints, or I made a bad assumption.  The second page of the plans shows the flat reduces the diameter from 32mm to 29.5mm, but I failed to notice the detail of the cylinder shows the flat containing these ports has a diameter of 29.86mm.  That would have given me a bit extra working room.  I think the plans intended the two flats to be different and I made them the same.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_182235_zpsuguftuzy.jpg)

Here I'm drilling to a depth of (44-12)/2 = 16mm ~ 0.630".  That's a lot of spins of my DI to count!  This is a 3mm hole and I used a #31 drill bit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_182354_zps2giyetqv.jpg)

And here is victory.  It's good when the drill bit shows up where it is supposed to be :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_182611_zpsvi4okljr.jpg)

The final bit of this port is to open it up on the edge into the cylinder.  I decided to do this with a tiny 1/8" end mill in my chuck.  This was a BAD IDEA because I was reminded (again!) that chucks don't hold end mills that well.  The chuck started slipping and made a tiny mess of it, but it worked out well enough.  I need a better way to hold these tiny (< 1/4") end mills.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_183151_zps4yusaw4q.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_183421_zpsrh5nkyck.jpg)

Then I flipped it end for end and repeated the operations on the other end.  That other flat remains against the fixed jaw so everything stays lined up.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_184452_zpsgkesrxfc.jpg)

This time I went *much* more carefully with the 1/8" end mill and got a nice result.  This is 2mm deep which I calculated to about 0.080"
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_184920_zps4wkcijn9.jpg)

Everything didn't go perfect, but so far so good!

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on December 28, 2014, 10:16:51 PM
More nice progress Todd...looking good.

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on December 29, 2014, 02:47:39 AM
And yet more progress.  Thankfully, I'm getting more time in the shop than in front of the computer :)

Next I made the cylinder covers.   Here's the plan:

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap2_zps900ee9e0.png)

For both I chose to create the inset that fits the cylinder first, for a snug fit, and then do the rest.  That turned out to be a not-so-great idea, but I got through it anyway.  My working theory was that when I'd turn the part around and chuck it, some imperfections from chucking it would be hidden from view.  The problem is that 1.5mm isn't much to chuck.  I had to be very careful.

Recall I didn't have enough material when I did the cylinder (poor math on my part), so I had to hack off another length of 1 3/8" (35mm) aluminum rod.  Here you can see my spiffy new Enco bandsaw.  Well, maybe spiffy isn't the word for it...the instructions were the worst I'd ever seen and it was out of adjustment as bad as you can possibly imagine, but I got it running.  A nice Christmas present and saved me from getting a workout from the hacksaw (if that's a good thing...).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_190715_zps7rqpewfi.jpg)

I faced it and skimmed it very lightly.  It came out at about 34.6mm.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_192524_zpsgm78frqa.jpg)

I turned it down close to matching the cylinder.  I tried a couple different cutters, but none would produce a nice crisp shoulder.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_194759_zpsnuguuyuu.jpg)

So I cheated and used my parting tool.   It did a nice job cleaning it up.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_201957_zpsjon0c4fd.jpg)

I measured until I got real close, then I tested every few thousandths.  It will be held on with screws, but I wanted a reasonably snug fit.  It came out pretty good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_202120_zpsair84cym.jpg)

I'm making the front cover.  At this point I decided there is no way I can grip it well enough by the 1.5mm, so I used my parting tool to turn it down.  Is there a better cutter for doing this?  I have a wider pre-made carbide tool, but it chatters up a storm.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_202935_zpsjtcm2lzk.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_205659_zpscw7rcew7.jpg)

I added chamfers per the plan...
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_205957_zpsrtwski4j.jpg)

And then parted it off...
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_210342_zpsfuktv4n8.jpg)

I made the rear cover the same way.  Here I am adding the chamfers just ahead of parting it off.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141227_213116_zpsuangbglp.jpg)

Now, the fun part.  Chucking 1.5mm wasn't easy.  I needed to switch back to my tiny 3" 3-jaw chuck.  My 4-jaw had a bigger chamfer on the jaw tips that simply wouldn't grip something that small.  Here I am carefully facing the rear cover with a few very light skimming cuts.  It held ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_112517_zpse0fc9nex.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_113535_zps6sf81pom.jpg)

The front cover was more difficult.  Here I am finishing up, but I needed to make several passes to shorten the nub to spec, and I got too aggressive.  Fortunately it fell away rather than jamming and tearing to pieces.  It only got banged up on the nub which I was facing down anyway.  A few more passes and all evidence was gone.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_115156_zpsd1sforu4.jpg)

Next I needed to drill for the piston rod.  This raised the question, what size piston rod should I use?  The plan calls for 4mm, but I don't have any of that, and it would certainly be crazy to try to turn such a thing.  I could go with 5/32 (0.156" / 3.97mm) or 3/16 (0.188" / 4.76mm).  I decided to go with 3/16 for a couple of reasons.  Looking ahead, I saw that the piston rod was to be threaded on both ends.  The plan calls for M3 on the piston end, and M4 on the crosshead end.  I'm sure both could be the same, but I decided I would stick to the spirit of it and go with 6-32 and 8-32.  The major diameter of #8 is 0.1640 which is a bit too big for 5/32.  The other reason was that I had 3/16 on hand! :).   So I cut a length of 3/16 stainless rod to have on hand for test fits, and got out a 3/16 drill bit.  I used a starter bit (not shown) and then drilled it through.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_124758_zpsp5v9afqo.jpg)

The rod fit nice and smooth.  Maybe I should have drilled undersized and reamed it, but too late for that now.  I'm a little more worried about it being ever-so-slightly off center, though, since I had to take it out of the chuck.  Maybe there was no way to avoid that, even if I turned the nub side first.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_124832_zpsp52oveoe.jpg)

Next I needed to drill and tap for a piston rod guide.  This is marked as M8.   I decided to go with 5/16-24 which is 7.94mm.  This called for an I drill bit.  You metric guys must be laughing right now.  Depth was 6mm which I rounded to 1/4" by eyeballing the tailstock depth markings.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_125107_zpslq7eukau.jpg)

Tapping was quick work in aluminum
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_125244_zpsqls7oq77.jpg)

Next was time to make the piston rod guide that threads into that hole I just tapped.  It's made of hex brass and here is the plan for it.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap3_zps1dacc149.png)

I chucked some 3/8" hex brass (9.53mm), turned it and threaded it for 5/16-24 threads to match the front cover.  Not much to say here, so enjoy the slide show :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_155330_zpsucpecffi.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_155620_zps6blhslgk.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_192029_zpswfet9vcp.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_192549_zpsbthwc95v.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_192934_zpspes2iv7r.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_193223_zpsuwmi1ocj.jpg)

And here's the piston so far.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141228_193849_zpsflzwnfel.jpg)

It'll mount horizontally, of course, but for the moment I'm not drilling for the screws just yet.  I'd like to make and test the piston with the piston rod to make sure the front cover fits well enough.  If it doesn't I'll remake it without worrying about how to line up the holes.  Hopefully that will get done tomorrow, and I'll clean up the piston rod guide a bit, too.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on December 29, 2014, 02:56:33 AM
By the way, I thought I should mention that I've been finding this chart to be very useful for metric/imperial conversions:

http://www.smithbearing.com/pdf/ENG-FractionalChart.pdf

Rather than get out a calculator, I can eyeball for the metric or imperial number I am trying to find.   And it works better than a calculator because if I look up 4mm I see that is 0.1575 for which there is no imperial drill bit.  However, it is quick to see the slightly larger #21 and smaller #22 glancing at this chart.

The only error I've spotted is that it lists 13/16 for 3/16ths -- an obvious typo.  The only thing lacking from the imperial side of things is another column indicating screw sizes.  I have a second chart for that.

Todd
Title: Re: Pottymill horizontal engine build
Post by: arnoldb on December 29, 2014, 06:03:24 PM
Good going Todd - you're moving right along with this one  :praise2:

From a "Metric" guy looking in from the other side of the imperial/metric divide: There's nothing wrong at all about how you're going about your measurements, and definitely no laughing.  It's really great to see someone just get on with things and using the best/closest equivalents  :ThumbsUp:

As far as using the parting tool the way you did, I see nothing wrong with that.  From my point of view, there's no fixed "rules" in model engineering, other than keeping things as safe as possible. If a tool and method works in that framework, it's a good way to get the job done.

The cutter in the drill chuck (or lathe chuck from my own experience  ;) )...  Yes, it will "walk out" if pushing the cuts a bit hard.  Unlike the shanks of drill bits which are usually not hardened, both the milling cutter's shank and the chuck jaws are hardened.  This results in a poor grip.  If at all possible, save up a bit, and buy some collets and a collet chuck (or make the collets and/or chuck yourself - it's good machining exercise).  Even el-cheapo collets work better than the drill chuck  :ThumbsUp:

Kind regards, Arnold
Title: Re: Pottymill horizontal engine build
Post by: Roger B on December 29, 2014, 06:32:01 PM
Good start on the engine  :ThumbsUp:  :ThumbsUp: As Arnold says, I you feel it's safe and it works that's a solution to the problem  :) No one ever has all the tools and fixtures to do everything the "correct" way  :headscratch:
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on December 29, 2014, 06:54:11 PM
Dizzying progress there Todd  :insane:  but I a thoroughly enjoying it!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on December 30, 2014, 04:27:25 AM
I got lots more progress today after a root canal.  I bet that's the first use of that opening sentence here on MEM :).  Yeah, a root canal sucks, but it's amazing how much better it feels when it is all done.

Making the piston and piston rod

The piston in this engine has graphite packing, which is unlike the other engines I have made previously.  Those engines had carefully fit pistons with no such seal.  I decided I would fit it well anyway and use the graphite packing simply for a better seal.  Since I know nothing about this, I figured that if the packing doesn't do any good, the piston will be in good shape.

I started with the piston rod.  The plan called for this to be threaded M3 on the piston end and M4 on the other end.  Yesterday I declared they could just as well be the same, but today I noticed a little detail in the plan.  On the piston end the piston rod sits in a shallow hole before it threads.  I suppose that makes the joint stronger, and it does require it be a smaller thread so the rod has a bit of a shoulder.   Since I am working imperial, I decided 6-32 would work nicely for the piston and, and 8-32 for the other end.   Nothing complicated but here is the 6-32 end.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_114733_zpszakijttb.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_115349_zpsbyh6v8rd.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_120320_zpssmbnuefu.jpg)

And here is the result of the 8-32 end which is much longer for an adjustment nut.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_122716_zps4nvksgbw.jpg)

Now it was time for the piston since I have the rod to thread into it.  The piston is 16mm which is a bit larger than 5/16".  I indicated a length of 3/4" brass using my little indicator holder I made a few months ago (thread over here:  http://www.modelenginemaker.com/index.php?topic=3936.0).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_130554_zpsr9aywodb.jpg)

I turned it until I got a good fit with the cylinder.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_132318_zpszgjnjcsk.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_133402_zpsxzrahmbu.jpg)

I cut a practice groove with my parting tool.  This groove is where I will need to part off the brass anyway and here I am testing fit of the graphite.  Stew's drawing showed this groove as 2mm wide, but I suppose it's all dependent on the packing used.  I picked up some packing and it seemed to fit pretty well in a groove this wide (2nd photo).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_134140_zpsjzfm5hvq.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_134622_zpsmbyalvbh.jpg)

The packing seemed to be rather deep in my test, so I decided my final depth would be a bit lighter.  I believe it was 0.080".  I eyeballed the center of the piston and cut this groove.  From the photo it appears I leaned to the left a little, but it won't matter.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_135007_zpsszbknqvi.jpg)

Next I drilled and tapped for 6-32 going a bit extra deep since I was going to part it off anyway.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_135548_zpsfjnjqfex.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_140206_zps8v0etfym.jpg)

And finally I drilled a recess hole for fitting the piston rod.  This was 5/16" to match the rod.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_140534_zpszeu126vr.jpg)

Here's a test fit.  Looking good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_140611_zpsojkto3fj.jpg)

And then I parted it off.  My AXA tool post along with tuning my lathe has made this *much* easier than it was 6 months ago.  The tuning provided most of the help, but the mass of the toolpost doesn't hurt (ok, I'm trying to justify the purchase :)).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_141039_zpsew4zj6kr.jpg)

And here's the piston with rod.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_141330_zpsmlmtcyq6.jpg)

I noticed the piston was a little sloppy, so I chucked the piston rod and lightly faced the piston.  Yeah, nobody will see it, but I knew it looked yucky.   All fixed now.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_142851_zpsjjlllngh.jpg)

Finally I did a little polishing to get a nice fit with the cylinder.  One end of the cylinder was a bit tighter than the other -- evidence of poor boring I suppose.  I used the fine metal grinding compound to work through that, then finished off with simichrome.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_145119_zpsmpqlxzyt.jpg)

Bolting on the front cover

I took the cylinder, front cylinder cover, and piston over to the mill.  The piston served as a nice means to center the mill without indicators.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_161230_zpsahbitkrm.jpg)

The cover has a simple 4-bolt pattern that's a square.  The cylinder is already square to my vice since it has a flat, so all I needed to do was move the table to a corner of the square.  The plan called for the pattern in a 24mm diameter.  That's a 12mm radius, but since I'm going diagonal to a corner I needed to divide by sqrt(2).  I thought about setting up my RT, but decided the practice I would get wouldn't be worth the effort.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_165412_zpspvassect.jpg)

I drilled and tapped for 4-40 bolts I got from microfasteners a while back.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_165607_zpsqurljvcl.jpg)

They looked nice indeed.  When I worked on the rear cylinder cover I changed the procedure a bit for the better.  Here I was installing the nice little bolts, but later I realized I should be using SHCS since it's much less fussy and takes much less room to install those temporarily in the tight space within my mill.  I wanted to bolt it down so it doesn't move for the remaining holes.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_170706_zpsrx9vhttt.jpg)

Since this post is long enough already, I'll skip ahead to the last hole.  I don't have DRO, but they came out real close to perfect, but not quite good enough.  I marked the first hole on the back side of the cover with a scratch so I could align it properly for the best fit as I disassembled and reassembled the cylinder.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_173031_zpstawddpl4.jpg)

Next I drilled out the top cover holes.  I set the Z stop on the mill and did them all by rotating each hole to this position.  For the rear cover I changed this procedure, too.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_173531_zpswfyzwbhq.jpg)

Bolting on the rear cover

As I mentioned earlier, I tried a slightly different procedure for the rear cover.  I thought I'd document it for anyone else making this engine.  I think it worked slightly better.  I started by centering the cylinder on the back side.  Note that I used the front cover and piston assembly for this.  Why not? :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_183531_zpsbb0lxtcb.jpg)

I'll show this starting with the third hole.  Each was the same.  I simply held the cover with my hand for the first hole, and the later holes were held by bolts in the earlier holes.  Note that I'm using temporary socket head cap screws here.  Much easier to tighten them in the cramped space.   Here I have already made a starter hole and I'm about to drill to depth.  My bolts are 0.375" so I'm drilling to 0.450" and using a DI in the back to measure my progress.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_190641_zpsj1qhompc.jpg)

Next I installed a larger drill for a clearance hole for the cover.  Here I am setting the Z depth stop on my mill.  On the last hole I realized the shim wasn't necessary.  Just let the bit settle in the hole and it will make a nice chamfer for starting the tap.  After setting the stop, I'd place the cover on and let the drill settle into the hole.  It worked well, although I had to remove the cover for each hole.  But with SHCS's that wasn't difficult.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_190902_zpsina9badg.jpg)

After drilling the cover, I'd chuck the tap and make the threads with the mill powered off.  This was a bit tricky for 4-40 (i.e. tiny) threads in aluminum.  I needed a light touch to make sure I didn't strip them out.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_192230_zpsv9w2aidw.jpg)

Adding the Graphite Packing

The last step for the cylinder was adding the graphite packing.  I have no real experience with this.   Here I jammed it in.  Pretty messy and it won't fit the cylinder of course.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_200909_zpsjh8s1rud.jpg)

I took it over to a hard surface, my vice, and pressed it in.  Looking better.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_201049_zps5cggffhu.jpg)

I could actually press it into the cylinder.  Here the back cylinder cover is removed for this.  It shaved off some excess :).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_201140_zpscv0ckchk.jpg)

I dusted off the excess and scraped other obvious bits off with a razor.  Now it was looking good, and fit pretty good too.  I had to use a bit of simichrome on the piston rod (not shown) but other than that, it didn't require more tuning.  With the covers on it almost makes a chuff chuff when I slide it back and forth.  Feeling pretty good about it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_201622_zpsvmz1lb12.jpg)

Here are some shots of the final cylinder.  It needs a little cleanup and polish of course, and also needs the slide valve which I'll make next.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_203537_zpsrq1qt9tn.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_203551_zpssqphlaye.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141229_203641_zpslo0louex.jpg)

Thanks for looking in...

Todd
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on December 30, 2014, 05:59:19 AM
Hi Todd

From your pictures it looks like you've over packed the piston with the graphite, you don't need to pack it solid just enough fill the groove it will swell a little and hold oil, these little engines don't produce a lot of spare power to overcome any tightness so its better to keep things on the slack side. Instead of graphite you could pack the piston with PTFE plumbing tape just twist it into a rope and wrap it into the groove.

The same goes for the piston rod and valve stem glands, for these first pack the gland and tighten up the stuffing nut to consolidate the packing then slacken it off a touch for running

Air/steam engines don't need the same close fitting pistons the same as a Petrol engine.

Hope this helps

Stew

Title: Re: Pottymill horizontal engine build
Post by: vcutajar on December 30, 2014, 12:48:15 PM
I had that exact same problem like you when I used the graphite yarn in my Corliss piston. Messy process.  Like you it was also my first time using using the yarn.  I tend to learn these things by trial and error, hopefully not many errors.

Most probably your engine would also work without the packing.

Vince
Title: Re: Pottymill horizontal engine build
Post by: tinglett on December 30, 2014, 03:35:18 PM
Vince, Stew,

Thanks for the advice on the packing.  I tried out some PTFE tape and it seems to work great.  I have plenty of this stuff in the shop and chose to use some that is intended for gas lines since I don't ordinarily use the stuff anyway.  As you can see, it was trivial to form it into a rope.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_091618_zpshf2jc2zy.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_091825_zpsype7ckbx.jpg)

It seems to work as smooth as the graphite, and was much less fussy to put in.  Of course less graphite may have been less fussy, too.  My graphite was stranded, and I think I could peel off a few strands to make it thinner.  It's messy, though, with all that graphite.  The gas line PTFE seems thinker than the usual stuff I've used for water pipes.  I may try the latter also when it comes time to tune up the engine, but I think what I've got will work as-is.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on December 31, 2014, 02:03:25 AM
Slower progress today with many distractions (i.e. kids :)), but I still managed to get the the majority of the valve chest made.

The Valve Chest.

Here is the plan for the valve chest.  I had to stare at it a bit to make sure I was thinking straight as the valve is off center.  I was thrown off course briefly because the passage holes for the cylinder (these are 12mm apart) are 3mm diameter, while those on the cylinder are 4mm diameter.  This is convenient as it gives me a bit of room for error.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap4_zpsd8a8bd64.png)


The valve chest is 16mm square aluminum bar.  I opted to go with 5/8" this time, which is slightly undersized at 15.88mm.  I chose not to mill it square as the stock seemed pretty good as-is, and only one side really needs to be accurate to fit against the cylinder.  I figure I could lap that later if I must.  It was already undersized after all.  Here I am milling to the plan length, but I forgot to test it against the actual cylinder.  Fortunately it fit perfectly.  It could be undersized, but oversize will get in the way of the cylinder covers.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_103720_zpse2xx1rb4.jpg)

I needed to bore for the valve mechanism down the length of the valve chest.  I decided to do this on the lathe with my 4-jaw chuck and gave it the proper offset.  I centered it first, and then pushed it 8-6.35=1.65mm (0.065") to the back.  I noticed that the bar was a bit more than 1 thousandth thicker in one direction, so I chose to use that dimension for the offset.  If I lap it, this extra material will disappear.  Ok, I know it won't matter, but I'm just thinking through for future picky engines where it might matter :).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_112634_zpsotfewfca.jpg)

For an operation like this, I've been learning to pull out the drills I will need ahead of time, and I put all others away to minimize my chance of screwup.  Here the ducks are in a row in front of my lathe.  The plan calls for a 6mm hole, which is 0.236".  I was going to pull out a letter drill for this, but it occurred to me that 0.250 isn't that far off, and I have a reamer for that.  Actually, I'm using an under-reamer so it will be 0.249" and I'm hoping the valve will work just a little better for the effort.  The extra drill bit is 3/16" that I used for the initial hole.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_113045_zps7rndk5gq.jpg)

Here's the slideshow of the operation.  Not exciting, but I took the pics so here they are.  Any tips are welcome if you see anything you'd improve if you were doing it.  The reamer did make a super smooth hole, but I know it isn't necessarily straight (i.e. I didn't bore it), and I'm also going to drill ports into it, which will mess up the inside.  Is there a better order of operations for that?  I could have drilled the ports first and then drilled this hole, I suppose, but then I'd have to worry about the depth of the ports (photos of that coming up).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_113340_zpsda1niwie.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_114835_zpsi2nxgjyu.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_115308_zpsrbkfqemo.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_115459_zpsts0b7itz.jpg)

There is a recess at the working end of the valve chest for a value guide.  This was 7mm so I chose a J drill bit to be the closest match.  This was to be 5mm deep, so I setup a dial indicator to measure the depth.  I need a better way to do this as my setup is pretty goofy.  I should probably attach a scale to the tailstock.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_164333_zpszvfhrgev.jpg)

Next was time to drill the ports.  I placed the part in the mill with the valve passage down low.  This is the side that mates with the cylinder, and it makes sense the passage is further away so the mechanism clears the cylinder as it does its work.  I centered the part on the Y axis, located the end with the 7mm recess hole (the "working" end), and then located down X to the right position.  Fortunately, I had jotted down my conversions when I made the cylinder so I knew that this hole should be 0.625" from this end, and the next hole is 0.472" down the X axis.  I've been jotting these numbers, and even my conversions to full dial rotations plus extra ticks (remember I don't have a DRO), and that helped a lot here.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_175129_zpsxjrhmklf.jpg)

Here I skipped some photos to show the second port.  Note that the printing on the metal mates with the cylinder for orientation for future photos.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_175541_zpsujx5verf.jpg)

And here it is lined up with the cylinder.  Looks like a match!   Note that I picked a slightly large starter drill, which is why the holes in the valve chest look like that.  I decided it was close enough, and the next size smaller is quite a bit smaller.  It still constricts to 3mm (a #31 drill) for what that's worth.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_175627_zpsa9bne2hv.jpg)

Next I rotated the chest, keeping the working end to the right as in the previous photo.  I'll be drilling exhaust ports next.  These are spaced wider than the ports into the cylinder.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_180852_zpsmzfeu1nw.jpg)

I ALMOST screwed up!  I left the part centered but at the last moment realized that the valve passage is now closer to the fixed jaw of the vice.  Doh!  Fortunately I looked down the end and noticed this.  Here I am locating the center which is 6.35mm from the fixed-jaw edge (rather than 8mm on center) and this is followed by a pic that shows it corrected.  These holes are 4mm so I used a #21 drill bit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_181221_zpsforg1mg6.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_181545_zpshbhbexod.jpg)

And I'll skip ahead to show the two exhaust ports.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_182105_zpsebc70ndo.jpg)

Finally, I flipped it end-for-end so I didn't need to change Y.  This meant the working end was now to the left, so I measured from there to stay consistent.  This last hole is the intake port where the air hose will attach.  This is also a 4mm hole, so I used my #21 drill bit again.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_182343_zpsjwg2cht9.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_182937_zpssvpbfcpo.jpg)

And there it is.  I wish I could prevent the chuck jaws from scuffing it up like that.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141230_183253_zpsyfkrg0sb.jpg)

Note that there are some additional holes that need drilling to attach the intake air fitting, the valve guide, and to attach the entire valve chest to the cylinder (a pattern of 8 screws).  I'll drill these when I make each part so they are aligned.  These will be teeny tiny screws and just a hair of alignment trouble won't be good at all.

Todd
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on December 31, 2014, 06:26:11 AM
Going good Todd

"And there it is.  I wish I could prevent the chuck jaws from scuffing it up like that."

Grip it with some shim from a cut up old drinks can.

Stew
Title: Re: Pottymill horizontal engine build
Post by: Roger B on December 31, 2014, 08:30:52 AM
Coming along well  :ThumbsUp:  :ThumbsUp: Your DTI on the tailstock looks fine to me. That's the sort of thing I do  ::)
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 01, 2015, 01:58:54 AM
I got a few teeny tiny parts made today.  I decided to call it a night considering it's the end of the year.  Happy new year! :)

The Piston Valve.

I decided the piston valve was next.  I'll fit it to the valve chest I made yesterday, and then use it as a guide to make sure all the other bits fit ok.  On starting this, I realized that I should make the valve rod first.  This is a 50mm rod threaded on one end to join with the piston valve.  The print calls for 3mm, so I went with 0.125" which is slightly larger.  The print called for a M3 thread for a length of 5mm on the end.  I decided to go with 4-40 thread which is very close.

You can see that I didn't need to turn down the rod much.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_161552_zps7p2qmeyg.jpg)

And here it is with the threads.  Easy enough.  It got a bit longer than 5mm, though, but fortunately I cut the rod a bit long just in case.  Looking ahead, I don't see this as too critical anyway.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_162224_zpsmctozeuw.jpg)

Now I can make the piston valve.  Here's the plan for it.  There are so many dimensions it's a bit hard to actually see the piston in there.  It looks like a thread spool.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap5_zps963d3d9c.png)

The piston needs to fit the valve chest which I reamed to 0.249".  So I pulled out some 0.250" rod and faced it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_163010_zpse7w9hvvo.jpg)

Then I drilled and tapped a 4-40 hole to mate with the valve rod I made a few minutes earlier.  I did use a starter drill (not shown).  I wanted this to be pretty accurate depth, so I'm measuring with a DI again.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_164106_zps945ctakf.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_164458_zpsroe9mjxv.jpg)

A test fit is good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_164720_zpsdahx6aqq.jpg)

Next I drilled a shallow counterbore to fit the diameter of the valve rod, which is 0.125"  I just eyeballed the depth on this one.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_164947_zpshnohfwkx.jpg)

It took a few test fits for this one.  The valve rod threads were a bit long, so I went to the grinder 2 or 3 times to shorten it up a bit until it fit just right as seen here.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_165402_zpswvpqh6nz.jpg)

Now it was time to turn out the spool area of the valve piston.  Here I slid it out of the chuck a ways, painted it with layout dye, and have measured in 3.5mm as called for by the plan.  I'm using my parting tool for this work.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_170657_zpsz1eva6yy.jpg)

Here I'm cutting part of the depth.  I'm mainly working on the right-to-left measurements.  It should be 3.5mm on each end with a recess of 8mm and an overall length of 15mm.  I nudged the cross slide to sneak up on it and made frequent measurements to get this as close as I could get.  Not difficult at all.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_171150_zpsuvwqz5wx.jpg)

Now I have the length measured for parting off, but before I weaken that anymore, I'm ready to plunge to full depth.  Remember my 4-40 thread is on the right end.  This made me a little nervous as I went to the full depth...but it came out fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_171732_zpswigjhlde.jpg)

Here's full depth.  Nothing fell apart.  A good sign :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_172003_zpsp6wospdo.jpg)

I hit it lightly with scotch brite pad and filed the edges slightly (not shown) to get ready for a test fit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_172147_zpsfpdjw6o0.jpg)

And I did get a nice fit with the valve chest.  Not snug or loose.  Lucky.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_172206_zps836f7jij.jpg)

Then I parted it off.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_172253_zpsvm5ilumz.jpg)

And here's the valve piston next to the valve chest.  I really need to clean up the ugly scratches on the valve chest :(.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_172711_zps3ruarzyt.jpg)

Now I can finally provide a family shot!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_172828_zpspbcdxr6r.jpg)

The Valve Guide Stuffing Box.

The last part today is the valve guide stuffing box.  It fits in the 7mm counterbore in the front end of the valve chest and will hold packing around the valve rod.  The plan looks like this.  It's a real tiny part!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap6_zps310c92a1.png)

I had written that I made the counterbore with a J drill bit, which is 0.276, and is almost exactly 7mm.  The full diameter of this part is 8mm, so I found and faced a length of 5/16" (0.3125") brass rod and turned 5mm of it down to 0.276.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_175222_zps51dpscqu.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_175617_zpssiunhzcd.jpg)

And then a test fit.  Umm....not so good.  I got a little too aggressive and should have checked it earlier :(
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_175655_zpsw5d1t4vq.jpg)

This was only 5mm of material so nothing really lost but some time.  I parted off the scrap and tried again.  This time success!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_180528_zpsxqfrdhz2.jpg)

Next I drilled for the 0.125" valve rod.  I'm working from the bottom of this part right now.  Note that the top has a 8mm rim to it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_180824_zpsaxxf4iby.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_181032_zpslycdcizw.jpg)

I got a very nice fit as far as I could tell at this point.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_181110_zpsks2bsjk7.jpg)

Next was time to part it off and turn it around in the chuck and face it.  I chucked it snug, but not too hard.  I don't want to mess up the fit too much, but jaw marks won't be seen at least.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_181409_zps3g4flebd.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_181851_zpsherrk5sa.jpg)

Now the fun part.  It needed to be drilled out 6mm for a 5mm depth.  This had me worried...not much material left after that!  Here I used a starter drill which was already a pretty large fraction of the material.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_182332_zpswscdkphg.jpg)

The 6mm hole was going to be made with a B drill bit.  I held it up to the started hole and decided I needed to have the starter drill do a bit more countersinking.  I didn't want the B drill to wander too much.  There simply isn't much room to wander.  Here's a pic of better use of the starter drill.  Somewhere I was told to always get a little of the countersink going so a drill bit can follow better.  That seems logical to me.  Here I wanted as much as I could get.  It's almost exactly 6mm.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_182725_zpsk4mpvr2s.jpg)

And here I do the drilling with a DI.  Can't go too deep either!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_183528_zpsfdcgpwnl.jpg)

There's the little guy.  Not much weight left of the little brass that went into it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_184134_zps1qn2ydte.jpg)

And here's the fit in the valve chest with the piston valve installed.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20141231_184309_zpskfjbnjy7.jpg)

That's all for today.  I know I posted a LOT of pictures and I hope they are useful for somebody.  Tomorrow I will make the valve rod guide that fits into this stuffing box, the air connection fitting, and the valve chest end cover.  We'll see if I can get them all done, and that will finish the valve chest assembly.  This assumes I don't party too much tonight :).

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on January 01, 2015, 02:46:42 AM
You are making great progress Todd. Once you get done with all the holes in the valve chest, a little time on a surface plate with some 320 or finer grit sandpaper will smooth things out and likely  remove most if not all of the scuff marks. I often leave a couple of thousandths of extra material just for that purpose.

Still following alone and enjoying the build.

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 03, 2015, 03:33:22 AM
I'm getting behind with the documentation.  Here's a tiny update, and I'll get more written down tomorrow.

The Valve Chest End Closure

It doesn't get any easier than this.  The valve chest was drilled and reamed all the way through.  The back end needs to be covered up.  It's a simple aluminum cover.

The cover is to be 8mm in diameter.  I faced off some 3/8" Aluminum rod.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_112642_zpseagd4db5.jpg)

I turned a length down to 8mm, which is 0.315".  Only 60 thousandths to remove.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_113440_zpsctpetnxy.jpg)

Next I turned a bit more to fit into the valve chest.  I had reamed this to 0.249" so I snuck up on it and tested until I got a tight fit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_114507_zps5hdrge6p.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_114535_zpsmzp1ipei.jpg)

And then parted off.  I pretty much eyeballed these thicknesses.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_114647_zpsxbjzauvd.jpg)

And there it is.  Not much to look at.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_115053_zps3d722uas.jpg)

But...it makes a nice little SNAP when I press it into the valve chest with my fingers.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_115231_zpshoo74kn4.jpg)

More exciting stuff tomorrow...

Todd
(http://)
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 03, 2015, 07:27:01 PM
The Valve Rod Guide

Next is the valve rod guide which slides into the valve guide stuffing box I had made earlier.  Here is the plan, and recall I decided to use 0.125" rod for the valve rod since I'm working partly with imperial measurements in my shop.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap7_zps188a8542.png)

I also decided to use 2-56 "bolts" for attaching it.  I haven't made threads for something so tiny before.  I also needed to create the shape.  I've seen reference to "filing buttons" many times on this board and thought I'd make my own attempt at making some to see how it goes.  The part is very small, so I figured filing wouldn't take long.

The part is 8mm by 15mm so I found some 3/8" by 5/8" brass bar which was darn close.   Here I am indicating it in the 4-jaw.  I've been using the 4-jaw a lot and getting pretty good at doing this :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_122257_zpsglofnifp.jpg)

With an interrupted cut, I used a pre-made carbide cutter.  If I wreck it, I'll just throw it away.  But it was no cause for alarm.  It faced just fine, though a bit rough with this cutter.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_122907_zpsxmcxdutv.jpg)

I then turned to diameter to fit the valve guide stuffing box I had already made.  I switched to my parting tool to get a nice shoulder.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_162915_zps65fzt8sn.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_164257_zpsqc0i0imn.jpg)

Doh!  I went too far again.  You'd think I'd learn.  I parted off the waste, but left a little bit as a reminder of what "too far" looks like.  This time went fine and I got a good fit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_164751_zpsaamhlrk5.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_165955_zpsyvebl639.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_171057_zpsw2taqajn.jpg)

I cleaned up the shoulder and parted off the excess to match the plan.  It is designed to stick out a bit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_171357_zps7udpm3zb.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_171900_zpsaa2ujb2u.jpg)

Next was time to drill out the passage.  The plan calls for 4mm, but my valve rod is 0.125" so that's what I used.  I estimated the depth knowing my tailstock runs 1/16" per crank.  That's good enough because I'll part off the excess anyway.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_180127_zpsf4qhpwto.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_180325_zpsfj3udgwe.jpg)

A test fit of the piston valve and rod for sanity.  Looking good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_180411_zpsldg3bgr0.jpg)

Next...part it off.  This actually went way better than I thought it might, considering the interrupted cut.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_180556_zps0hw0ag1n.jpg)

I turned it around and chucked it to face it, rather than file it.  This is the side you'll see, so I wanted it to look nice.  If I couldn't reliably chuck it, I would turn to the file, but it worked fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_181252_zpsgzwst1fh.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_181502_zpsslayez89.jpg)

There it is...nice fit, but I still need to shape it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_181630_zpszzop02ij.jpg)

Before shaping it, I wanted to drill the holes for bolting it to the valve chest.  Here I have chucked it in the mill and am using a 0.125" drill bit to center it under the chuck.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_182500_zps9ye3fxzn.jpg)

I used a #50 drill for the 2-56 tapped hole and a #43 for the clearance hole in this part I am making.  I measured depth with a DI again.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_183129_zpsqlgajrrr.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_183445_zpsfjquyhhb.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_183704_zpse2pmgspf.jpg)

The tap was so fine, and I was working with "gooey" aluminum, so I decided to tap completely by hand.  I had already drilled the brass as a clearance hole, so that worked as a guide to help me hold it straight.  Note that I didn't even use the t-bar in the tap wrench.  I could easily twist it with my hand and was very paranoid about it.  I did the other side the same way.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_184205_zpsmviatqob.jpg)

Once I could remove the clamp, I used the tap once more to clean it out and go a little deeper.  I did this by hand again, rather than chucking it into the mill's chuck as I usually do.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_185315_zpspqaqyjee.jpg)

Filing Buttons

I have to admit, I've seen filing buttons used in posts here on MEM, and perhaps on other websites, but have never seen them mentioned in books, and I've certainly never used one.  So from here on I'm making this up as I go along.  Suggestions are more than welcome.

The first buttons I made were spacers for the bolt holes I just made.  The plan suggested a 2.2mm radius, a 4.4mm diameter which is 0.173".  I had some 3/16" (0.188") steel rod handy, so I drilled and tapped a length of it.  I tapped for 2-56 to match the bolt holes in the part.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_191225_zpsod18xv9i.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_191450_zpsfm3sysap.jpg)

I used the chuck in my tailstock as a guile for hand holding the tap.  I found if I opened the jaws just right, it guided the chamfer of the tap wrench perfectly.  I know I should drill a hole in the tap handle and use a center, but this worked fine.  It was a little harder to turn the tap in steel...but surprisingly not much.  If it started getting tight and felt like the tap might distort, I unscrewed it, cleaned and re-oiled it, and went at it again.  Worked good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_191630_zps8tfkvoaf.jpg)

Then I parted off two of these.   My first two buttons!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_192440_zpsujwcouzt.jpg)

I drilled for a clearance hole and parted off two more buttons from the same rod.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_194519_zpsmhsp1hrm.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_194858_zpsrwypcvr5.jpg)

Here are my two sets of buttons.  I really only needed one set, but I thought it might be handy to have an extra.  I'll use them both for filing this part.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_200018_zps3cdi3hmi.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_200803_zpsm7sfcrbc.jpg)

For the center button I could see two problems.  First, I could only place a button (realistically) on one side.  No big deal...less work in fact. But the other problem is that space is tight.  I can only fit a sliver of a button in the middle.  But that's ok.  This needed to be 8mm diameter which is 0.315".  I decided 3/8" (0.375) was close enough.  To provide clearance for the side buttons I just made, I clamped the rod in a vice and made some flats by eye using the mill.  I need to work on my eyeball skills...it was a little off.  I drilled it for a 0.125" hole to match the part.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_202815_zpspnei6uyz.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_203031_zpsco6nlj3c.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_203158_zpszdu5wc3t.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_203316_zpsimnrkrl7.jpg)

And here's how this button fits on the part.  I realized I could rock it back and forth to help guide more on the side I was currently going to file.  Cool.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_203659_zpsc4l8i1is.jpg)

Now on to filing.  I clamped it in a mini-vise and filed down the big chunks, trying not to actually touch the buttons.  This went pretty fast.  The hard part was finding spots for the vise to get a grip.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150101_204433_zpsjyyanejb.jpg)

I switched to a finer file and found that for the fine work it was easier to slide the part over the file than to move the file.  Here I am done with one side.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_094532_zpsqriykcoo.jpg)

I repeated with the other side.  This was going better than I imagined.  It was pretty easy to feel when the file started biting into the button.  The buttons weren't loose, so they wouldn't spin, nor were they hardened.  So I had to be careful.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_101854_zpsnozcy6pn.jpg)

A little touch-up with 320-grit sandpaper and I declare the part came out pretty darn good!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_102231_zpszh6stmda.jpg)

And here is how it fits into the valve guide stuffing box.  I'll show the bolts later.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_102421_zpstnbwzred.jpg)

Next up is the air connection.  This part looks very similar to the valve rod guide in this episode and I approached it more-or-less in the same way.

Thanks for checking in.  I'm pretty happy with how the filing worked out, but I'm still looking for any advice on how to do it better.  Or maybe just how to do it in a different way.

Todd
Title: Re: Pottymill horizontal engine build
Post by: ths on January 03, 2015, 09:18:24 PM
Great use of the filing buttons Todd. I'd never seen that particular method for shaping flanges before,, the end result looks great. Hugh.
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on January 04, 2015, 01:23:23 AM
Still looking great Todd. You are making some good progress...keep the updates coming :)

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 04, 2015, 04:48:07 AM
The Air Connection

This part looks very similar to the valve rod guide, and I made it pretty much the same.  Here's the plan for it.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap8_zpsdab7c366.png)

I decided I'd make the part as shown, but I'd also drill and tap it for 10-32 threads so I could add this fitting that I've used with my previous three engines.  The passage through this fitting is a bit larger than 2.3mm so I hope it will deliver enough air.  It's very convenient with the quick disconnect feature.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_105308_zps6ag7if1d.jpg)

I didn't happen to have any brass bar stock 1 inch wide, but I did have some 1 inch rod so I started with that.   I faced it, turned it down to the 8mm outside diameter which is a purely decorative measurement, drilled it through with a #39 drill for the 2.5mm hole, and then tapped it for 10-32 threads.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_122906_zpsrvjhrf0m.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_134015_zpsly3bxzve.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_142209_zpsdsggyeiv.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_142357_zpsmjtumpte.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_142613_zpsxiavgduj.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_142932_zpswks92avq.jpg)

I tested the quick disconnect fitting and it worked fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_143122_zpsm4buzolr.jpg)

I parted it off, then flipped it around and turned down the protrusion that fits into the valve chest.  It needed a little cleanup, which it got.  For the cleanup, I applied some layout dye because I had already gotten a nice fit and I wanted to see easily if I was skimming off any additional material.  I didn't bother trying to get a crisp shoulder.  Instead, I decided to apply a slight chamfer to the valve chest to make clearance for it (not shown).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_154008_zpsxx5a7h7m.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_155000_zpsbrobxgkw.jpg)

The fit was good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_155113_zpsxlse1ypv.jpg)

Next I moved it to the mill and centered the chuck on it by chucking the fitting.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_160148_zpsvuhffgqk.jpg)

Then I drilled and threaded the mounting holes.  I decided to use 3-48 "bolts" for this.  I threaded entirely by hand as I did with the valve rod guide even though these threads were slightly bigger.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_161532_zpstsq7n1su.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_161926_zpsugnz3n3e.jpg)

Now I could screw it down with a temp screw.  Previously I held it by hand, though it was snug in the valve chest, but now I couldn't let it move.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_162405_zps4kfsymwd.jpg)

I drilled and tapped the other side, and then tried the real bolts.  Looked good, though isn't the right shape yet.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_165427_zpssuuxnein.jpg)

I found a washer that fit underneath.  I'll used this to space it away from the valve chest and milled away a bunch of the material.  I didn't get fancy and try to mill diagonals, though, although I suppose I could have tried.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_165755_zps5nb8rfgf.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_171703_zpsl9zm3lmu.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_172231_zpskhbuvb5w.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_173054_zpsq1685h2t.jpg)

I machined a filing button to fit over the 8mm diameter side.  Since this side is tapped, I'll simply attach it with a 10-32 screw.  Well, a nice plan, but I found my screws were all relatively long so I had to get creative with a pile of washers.  It worked ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_183052_zpsjnmrln2y.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_185040_zpslxdmdi9n.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_185322_zps65vzwqyd.jpg)

I made a single filing button for one of the other holes.  There wasn't room on the top side for it, so I attached it on the back side.  The screw head still interfered with the large filing button, so I had to turn a little relief it that button.  I gave this little button threads as the 3-48 nuts I had on hand were larger than the button.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_191700_zpsof4cjanp.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_192136_zps5rrzqswr.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_194047_zpsqccivgjc.jpg)

With buttons on one side only, and different sides at that, I had to file carefully.  They didn't turn, nor were they hardened.  So I started filing.  Here's one side rough filed.  It only took 10 minutes...maybe less.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_195308_zpsw0xxxac6.jpg)

And here's the other side.  I see I got a little too aggressive on the first side, but it wasn't too bad.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_201604_zpsp6sdsyb4.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_201935_zpsq0las25u.jpg)

Here's it's done, though it needs a little cleanup.  The "bad spot" is on the right low side.  It jumps out at me, unfortunately.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_202557_zpstbfnmief.jpg)

But it looks pretty damn good installed on the valve chest :).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150102_203216_zpsebimbgba.jpg)

Another part checked off the list.  Thanks for looking in!

Todd
Title: Re: Pottymill horizontal engine build
Post by: Stilldrillin on January 04, 2015, 09:27:07 AM
But it looks pretty damn good installed on the valve chest :).
Todd

The whole assembly, is looking, "pretty damn good", Todd!  (http://freesmileyface.net/smiley/respect/respect-048.gif) (http://freesmileyface.net/free-respect-smileys.html)

Well done, and well shown....... (http://www.picgifs.com/smileys/smileys-and-emoticons/applause/smileys-applause-242316.gif) (http://www.picgifs.com/smileys/)

David D
Title: Re: Pottymill horizontal engine build
Post by: Roger B on January 04, 2015, 12:34:58 PM
Good progress  :praise2: I like your solution to making two bolt flanges  :ThumbsUp:  :ThumbsUp: I used a jig on the rotary table, that was probably too complicated  ::)
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 04, 2015, 10:46:58 PM
Attaching the Valve Chest to the Cylinder

I wrapped up last night drilling the valve chest for attachment to the cylinder.   There's good news and there's bad news.  This post is the good news part.

The valve chest is attached with 8 screws in a 2-row of 4 screw layout.  I didn't want to mess this up.  I also wanted a reliable process for position and depth since I don't have a DRO.  In particular, my mill is HORRIBLE for Z depth, so I need to resort to a DI always.  I thought I'd try to setup some stops for reasonable consistency and no fuss readings.  The process went well.  Here's what I did.

I first devised a means to clamp the valve chest and cylinder together.  This looked like it would work.  I had paper on the left side which is hard to see in this photo.  Is paper needed on both sides?
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_151049_zpsykwlszwz.jpg)

I disassembled the clamp, painted the top of the valve chest with layout dye and scratched in the layout with my caliper, then clamped it up again.  I haven't been doing layouts like this lately, but since I'm using dials and these parts have a lot of work in them, I thought it best as extra assist against screwups.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_170157_zpsuepxpjxk.jpg)

I planned to use 2-56 screws that are 3/4" long.  That means they'll only grip with 1/8" into the cylinder.  I decided to drill 3/8" into the cylinder in case I wanted to go with slightly longer screws.  That means using a #50 drill for the hole all the way into the cylinder, and then opening it up with a clearance hole with a #43 drill only in the valve chest.  I'd need to switch drill bits, so if I'm using a stop I'd need a way to replace a bit reasonably accurately.  I found a length of aluminum rod to use for this purpose as shown in the picture.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_194735_zpsfiklijbc.jpg)

Next, I brought down the drill with the mill powered off so it just touched the cylinder.  Note that I've removed the valve chest.  This is the depth of the valve chest and is where I want to stop the larger #43 drill.  In the following photo I show that I set the stop with a block of 3/8" aluminum.  The working theory is that if I drill to the aluminum block I will drill completely through the valve chest and reach the top of the cylinder.  If I remove the aluminum block I will drill 3/8" deep into the cylinder.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_194818_zpsuwqlpvyc.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_194823_zpsrimawqne.jpg)

Now I need to locate the position of the first bolt.  I wrote relative distances, including turns of the dials, on a nearby piece of paper.  Trying to reduce the screwups.  Fortunately, even with the stop in place I was able to reach the top of the valve chest in order to use the starter drill shown.   Lucky me.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_195944_zpscbt6ynyi.jpg)

It was a matter of repeating 8 times:  a) locate to position along X with Y locked;  b) use starter drill;  c) insert #50 drill using aluminum rod spacer with mill head completely raised; d) drill to full stop depth (into cylinder); e) insert #43 drill using aluminum rod spacer with mill head completely raised; f) drill to depth using extra spacer block.   It was step f that had me worried.  But somehow I never forgot that extra spacer block.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_200524_zpsadrnmiyx.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_200730_zpsggsf1mgo.jpg)

I repeated this for the first series of holes down the X axis and kept the Y locked.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_203128_zpsosrdxmcm.jpg)

Then I had to crank it back and account for backlash.  Remember I'm using dials.  I lowered the drill into the first hole with the mill powered off to double check. It was aligned.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_203404_zpsnfle3pma.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_203715_zpsm664yr1n.jpg)

It occurred to me before I started moving down X that I needed to adjust for backlash again because I was changing direction.  I lowered the bit back into the newly drilled hole and turned the dial to get rid of it and reset to zero.  All was well and I finished the second row of holes.  Maybe it would have been best to do the second row of holes in reverse.  The layout lines where helpful to give me confidence I was hitting the right spots.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150103_205938_zpsgauwc3cf.jpg)

With all the holes drilled, I removed the clamp and valve chest and tapped all the holes by hand.  This was actually very easy.  There is very little resistance to a 2-56 tap in aluminum.  I had to be careful not to strip any threads I created.  While I was at it, I measured the hole depths and they varied by only 6 thousandths.  I was surprised by that.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_101938_zpsjzemhdq1.jpg)

I'll switch to hex head bolts, but for now I screwed it on with these screws.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_102747_zps47n1ioct.jpg)

The next installment will document what isn't going so right.  Stay tuned.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 05, 2015, 12:25:54 AM
A Visit from the (self) Inspector

Inspection didn't go so well today.  Everything was looking pretty good, though as I looked closer I could see the valve chest was a little extra long.  That's why the cylinder covers weren't pressing down perfectly.  That'll be an easy fix...but I'll wait a bit.  I found (and created) more problems :(.

First, I was assembling the engine and noticed filings inside the cylinder.  What?  In my haste yesterday to make room for longer cylinder chest screws, I realized I hadn't completely analyzed the situation.  The screw holes I just drilled were peeking into the cylinder!  Damn.  I would have needed to be 1/16" shorter or so to avoid this.  If I had stuck to the original plan of 1/4" depth rather than 3/8" I would have been fine.  Sigh.  I cleaned it up and I don't think these will be a problem as they certainly will be sealed, and I could put some kind of goop down the holes to be sure.  It's the added friction I don't care for.  I think I'm going to leave it as-is.  At least they can't be seen without X-ray vision :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_102901_zps8uusmhlo.jpg)

Next, I noticed the valve piston would not move all the way across the valve chest.  There was a bit of material from a recently drilled hole (correctly drilled, at least).   As I pushed out the valve piston, it broke!  Blech.  I was worried about that spot.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_104355_zpspqkjyhzp.jpg)

Time to make a replacement valve piston.  I was cutting the first groove and it chattered and bent.  Blech #2!  The photo doesn't look bad...but it really is bent badly.  I've been having trouble parting again as I'm getting used to this new AXA parting tool holder.  I think my main problem is that it is angled up and I probably need to change the angle on my parting blades.  In this case the blade was riding just a little too low.  Fixed now, but not in time for this part.   I did manage to create a new valve piston, though.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_113821_zps2jzvqyrk.jpg)

Here are a couple pictures of the full assembly.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_154503_zpsmwvguagl.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_154516_zpspurar2py.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_181724_zpsy1dencfo.jpg)

Finish needs to be cleaned up.  I need to shorten the valve chest by 0.003" on each side.  I should probably replace the piston rod, and maybe the valve rod, as they've gotten beaten up as I've worked with it.  The trouble with both is that they are pretty tightly wedged into their corresponding pistons.  I haven't used locktite, so this is fixable.  If they really cause trouble, I can always re-make both rod+piston to solve this.

I was also able to test the cylinder.  I gave it 30 psi of air, while holding onto the valve chest end cover, and moving the valve back and forth will snap the cylinder back and forth.  The piston is a bit "sticky" on the far end, which I believe is due to the rough scrapes on the piston rod that is visible.

Now for the bad news, and Stew maybe already caught this.  I've somehow managed to swap the intake and exhaust sides of the cylinder chest!  Crud.  Note the flat is on the top side of the cylinder.  When I rotate it over, the intake will be facing down.  That's the result of a beginner reading a plan.  So I believe I have 3 options:

One other detail for idea #2 is that I'll need to be able to attach the parts in the flipped around position.  I checked this and found the valve chest does screw down fine in the reverse position (woot!), but my holes are ever so slightly off for swapping the end covers.  They are close, so I think drilling the covers for one size larger clearance hole would do the trick.

I'm leaning heavily to the first option.  I'll whip up an elbow of some sort for the fitting and see how it looks.  But I don't have great ideas for something to go over the exhaust holes.  I could make two flanges, or a single big flange of some kind.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 05, 2015, 02:41:23 AM
In reference to a fix for my dilemma from the previous post, I created an elbow that would allow the air fitting to work on the underside of the valve chest.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_203143_zpsbohrltns.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150104_203122_zpsawr4hnbn.jpg)

Not bad, but what should I do with those ugly exhaust ports?  Two small flanges?

Todd
Title: Re: Pottymill horizontal engine build
Post by: wagnmkr on January 05, 2015, 12:09:28 PM
Looking good so far ... a couple of minor problems, but everyone has them.

For the exhaust you could create two short pieces of brass pipe that are a tight push fit into the exhaust holes on the one end, and have those two merge into one, either going vertical or horizontal. Like a set of headers for a car.

I am starting on Stew's vertical, which has the same cylinder arrangement and that is what I am going to do.

Cheers

Tom
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 05, 2015, 01:58:07 PM
Thanks Tom...

I had forgotten about the other cylinder arrangements.  I should be careful not to call the holes "ugly" because they are certainly visible in those configs.  It's just that the brass looks so much more pimped :).  I'll experiment, but really I can put this off for a long time.  It will work fine without doing anything.

I am thinking about redoing the piston rod.  I wasn't too worried about the looks as the cross slide is a distraction from it, but it does bind a little and I don't need that.  If I sand it down it's going to have a sloppier fit.  I think now's the time to take care of this before I move on.

Todd
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on January 05, 2015, 06:10:17 PM
Hi Todd

It doesn't matter which way round you have the holes, leave things as they are.

You are making a really nice job.

Stew
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on January 05, 2015, 06:37:45 PM
I think your solution is just fine Todd, and as Stew said, your are doing a great job with the build. Great pictures too BTW!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 08, 2015, 04:10:37 PM
Not much progress with "real" work starting again, but I did spend some quality time cleaning up and tuning the cylinder assembly.   I'm going to leave it like this with air intake underneath.  Maybe I'll add some jazz to the exhaust, but not now.   Simple is good, too.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150107_184919_zpszmxshijm.jpg)

I polished out the roughness in the piston rod (not shown) and hope it didn't make too sloppy a fit.  If it did, I'll need to rework the rod.  The valve chest was indeed a bit over length and that is fixed now as well.  The whole thing is a little stiff, but I'm sure it will loosen up when I work it.

I already started working on bits for the cross head assembly.  Updates coming soon.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on January 08, 2015, 04:29:35 PM
That polished up nicely Todd. Looking forward to more as you have time. No fun having to go back to work after the holidays is it :)

Bill
Title: Re: Pottymill horizontal engine build
Post by: wagnmkr on January 08, 2015, 10:42:19 PM
Yes indeed, that is looking good.

Cheers

Tom
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 12, 2015, 11:49:38 PM
It's time to get back to documenting my work.  I accomplished a few things over the weekend.

The Cross Head

For the beginning of the cross head assembly, I made the cross head itself and a cross head pin that will mate with the connecting rod.  There are also slide bars and washers that will slide within slide bars and pillars that hold the slide bars.  I decided I should make those together so they fit well together.  So today it's the cross head and pin.  Here's the plan from Stew:

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap9_zpsf84dd8b2.png)

As usual I'll do the cross head and then turn the pin to match it.

I started with some 1/2" CRS bar stock which matches the 12.7mm dimension exactly.  I could have used 3/8"x1/2" as that matches the plan exactly, but this is what I had in my supply.  I faced it, turned the shoulder, and drilled and tapped for 8-32 which is how I threaded my piston rod.  I'm learning that when I make a choice like 8-32 as my substitute for M4 threads, I need to look forward in the print and write it down where it impacts other parts.  In this case I had written 8-32 for this part.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150107_190525_zps3k3zgcqh.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150107_195150_zpsddrnzzfq.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150107_200056_zpsxhdje9fo.jpg)

I chopped the part off the bar stock with my bandsaw and left a little extra.  Since the bar stock wasn't 3/8" thick, I had to mill off top and bottom as shown here.  I'm using my DI to measure the amount, which isn't a critical dimension.  Even if it was critical, I know I'm going to do some filing so I could simply use care to leave it oversize.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150107_204513_zpst7dkl0q7.jpg)

Next I rounded over the front edges with a file.  No filing buttons here.  I filed by eye and made a bevel first, which is easy to see if it is even width or not, and when I was satisfied, I did the final bit of rounding over.  This was quick work.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150107_211543_zpswjejlzgt.jpg)

Next I located and drilled the hole for the crank pin.  I went with a D bit size, which is 0.246"
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150108_202017_zpsutt4aspe.jpg)

I rotated the part 90 degrees in the vise (you can barely see the D-size hole I previously drilled) and then I started drilling out waste between the arms of this little part.   This didn't go so well at first because I hit the previously drill passage.   So much for drills!  But at least I didn't ruin the part.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150108_203507_zpsexzktdlj.jpg)

I switched to a 2-flute 1/4" end mill which worked much better.  Now I can hog out the inside of this thing.  I had centered the mill on the part so this was quick work moving in X.  Recall the part is over length so I could leave the bit on the right closed up.  I assume that's better for the vise.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150108_204236_zpsqzgtq2im.jpg)

Here it's almost done and looking better.  I wasn't too worried about the ends (certainly not the right end) and made light passes on the inside edges until they were at the proper thickness.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150108_205719_zpssgm8umwb.jpg)

Next, I drilled for pins.  I had to study this a bit, but I realized this makes sense.  The cross head doesn't pivot, and the slide bars will thread onto the cross head pin.  These little pins will keep the cross head pin from rotating and unscrewing the slide bars.  I suppose loctite might do the job, too.  I pulled out some 3/4" brass brads from my wood shop supplies, measured them, and found they would need a #63 bit.  The smallest bit I have is #60, so I looked again for larger brads, which turned out to be 1" and needing a tiny little #57.  It drilled way faster than I would have guessed.  For sure I needed a starter drill (not shown) for these holes.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_112728_zpsaxn5d9tw.jpg)

I centered these locking pins within the thickness of the material by eye.   As you can see, my eye isn't too accurate with the pin hole closest to me in this photo.  Oh well.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_113155_zpslejclyjy.jpg)

Next I machined off the excess length with an end mill on the edge of the vise.  I suppose I could have clamped it vertically in the middle of the vise and skimmed off the top in that position.  I took a few light passes so that nothing would snag and bend.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_115611_zpswnxg0yjj.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_115935_zpslsvpgpbo.jpg)

I found there was still some material remaining in the thickness of the arms of the part.  I clamped it in the middle of the vise, removed the parallels, and lightly took some passes.  I got a little too aggressive and popped it back like this.  Thankfully I didn't ruin the part (or me!).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_120340_zpspimnihnq.jpg)

I guess I was feeling lucky and went back at it despite my near miss.  I continued very light passes (< 5 thou) and it finished up fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_120551_zpslfroagdw.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_121126_zpsqsuuqhdc.jpg)

The corners still need rounding over and I decided I'll make buttons to help guide that.  But it occurred to me that I could locate those buttons with the cross head pin, so I decided to make the crank pin next.  Rounding will happen later.

The Cross Head Pin

Recall I made the cross head hole with a D bit which is 0.246.  Here I have some 1/4" rod and I skimmed those few thousandths until I got a nice snug fit.  It presses in with heavy finger pressure.  No press needed of course.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_144745_zpswv6n3mbd.jpg)

I decided to thread the ends for 10-32 so I turned the 7mm length down to the necessary size (0.190") and threaded it.  I turned it around, parted it off, and did the same.  Not much to it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_150529_zpsrjfllxkx.jpg)

You might notice I did better on the left than the right.  I did the right side threading first and found I couldn't get the thread all the way to the shoulder, so I used the parting tool clean it up.  On the left side I showed I learned something and used the parting tool up front to turn the minor diameter.  When I threaded it, the threads came out perfect right up to the shoulder.  Well, maybe the threads aren't exactly perfect, but I can run a nut right up to the shoulder.  I've never read how to do this before, but it sure turned out nice.  Or maybe I just got lucky.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_154702_zpsl1vclo7r.jpg)

Next I turned a 3/8" button and attached it with a nut on the 10-32 threads.  I could see this might work, but the nut is too big and would interfere with filing.  I didn't think to measure the nut.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_160453_zpsdtx9pcjo.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_160539_zpsdy3jypvt.jpg)

So plan B was simple enough.  Make a couple filing buttons that are tapped for 10-32 instead.  Note that I needed to drill a recess to clear the wider part of the cross head pin.  The buttons fit nice.  It was looking like easy filing ahead.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_163453_zpsbfmnhv5d.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_163530_zpshii7hew6.jpg)

And filing was fast and easy!  The nice thing was that this part was big enough to clamp.  Filing it down maybe took 2 minutes.  Maybe.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_163934_zps5sc0vzhj.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_164144_zps7kuqqrjj.jpg)

Spiffy.  And it looks right at home on the engine!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_165231_zpspjzk0gqc.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_165504_zpsij7tlio5.jpg)

And that's it for today.   Next up, I will switch to the connecting rod assembly, and then later I'll get back to finishing the remaining parts for the cross head assembly.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on January 13, 2015, 12:06:42 AM
 Another nice update Todd. Still following along eagerly here.

Bill
Title: Re: Pottymill horizontal engine build
Post by: Don1966 on January 13, 2015, 02:30:00 AM
Nice bit of work there Todd she's shaping up. pulling up a chair.  :cheers:

 :popcornsmall:
Don
Title: Re: Pottymill horizontal engine build
Post by: Jo on January 13, 2015, 08:11:39 AM
Hi Todd,

It is looking good  :ThumbsUp:

When you use the filing buttons if you file with the buttons , i.e. following the curve , rather than across you should find it easier to achieve the right curve. I also use a marker pen on my buttons/work so that I can see where the metal still has to come off the item ;)

Jo
Title: Re: Pottymill horizontal engine build
Post by: Jim Nic on January 13, 2015, 11:29:12 AM
Looking good Todd.  I'm following with interest as I plan to build Stew's Cross Single shortly which uses the same cylinder arrangement.
A point regarding filing buttons is that as well as filing with the curve of the button rather than across it as Jo says, if you arrange the buttons so that they are free to rotate your file will shape your part down to the point where it rides over the turning buttons but will not remove any metal from them thus ensuring a truer radius on your part and saving the buttons for use another time.  ;)
Jim
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 13, 2015, 05:19:45 PM
Thanks for the comments!

I have filed with the filing buttons when I switch to a fine file and hold it by hand.  I should include a photo of that, but I keep running out of hands :).  I should come up with some way of allowing the buttons to rotate, though.  Maybe it's because they are so small, but I keep coming up with solutions that won't do that.  Maybe I need to think a little harder.  Some kind of bushing could go over the screw first, I suppose.

I like the idea of using a marker as an indicator that I'm cutting into the button.  Maybe I should paint it with layout dye.  I've done that a few times on the lathe when I want to know precisely when I make contact with the work, and it works pretty good.

I'm really liking using buttons for this kind of work.  Honestly, I can't say I've seen them in any books or magazines.  Are there other names for them?  Seems odd.  But maybe I haven't read enough.  I've only been at this for a bit less than a year.

Todd
Title: Re: Pottymill horizontal engine build
Post by: Steamer5 on January 14, 2015, 06:50:40 AM
Hi Todd,
 Looking good.

For filing buttons I use a rod of the right dia for the holes threaded at both end, make it long enuff for nylock nuts both end your buttons & part, & a spring that goes over the rod between the locknut & one of the buttons on one side, adjust the tension on the spring to hold all together, file away! As you hit the buttons roll, the nyloc nuts hold all together. With out them the gnome gets to play with your nuts, as they fired from the spring!
A trick that I don't remember seeing taught to me by an old friend when filing a round end, is to start to file down the far side of the part, as you push forward drop the handle down the front side & you produce a rounded surface.......hope that makes sense.

Cheers Kerrin
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 19, 2015, 02:49:02 AM
The Connecting Rod

The connecting rod is formed by a main part that includes the rod with a nice decorative angle, a bearing brass on both ends...one of which is split in two parts for assembly, and a little end plate that bolts it together.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap10_zps1ad887d9.png)

I started on the main part since the other parts must be made to fit it.  I didn't happen to have any bar stock quite this size, so I went to my home center and got some hot rolled steel that would hopefully have a good enough finish.   I machined the ends, but decided to leave the long edges unmachined to maximize the material.  Later on I'd regret this, though it didn't foul anything up.

I'm going to turn this bar between centers to form this as a single part.  No soldering or threads to put it together.   I drilled both ends for centers, but found it hanging pretty far out in mid-air.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150110_201314_zpsckwgxjvp.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150111_135714_zpsbc9ukrvk.jpg)

This is a general problem I have with my lathe.  There isn't much room, and yet the headstock center (an MT3) sticks way out.  I need a driving pin longer than 2 inches.  I'd really like to find a center that isn't so long.  Rather than invent a solution now, I decided to go with plan B, and that was the setup Stew showed for his Dad's and Lad's engine which is a nearly identical arrangement.  This involves turning a little center that can slide into the chuck and the chuck jaws can drive the work.  It worked really well, and I'll remember this trick for the smaller parts.

I first turned a bit of 0.5 inch rod.  With my big AXA tool post, I found it more natural to turn this on the back side with the work spinning in reverse.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150111_141603_zpspz71mcka.jpg)

But there was trouble.  I was thinking a 0.5 inch rod would be plenty wide for centering a part that is only 0.25 inch thick...but it wasn't due to the way my chuck jaws are formed.  You can see how the jaws are going to drive the work, but it wasn't a rigid enough setup.  I tried working with it this way for a bit, but eventually decided to fix the situation.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150111_142423_zpsvks80dg9.jpg)

So I found some 0.75 inch rod and decided to turn down a stub for the center so it wouldn't get too deep in the chuck (the 0.5 inch center was deep enough).   I used my parting tool and guessed at the depth.  I was pretty close, but should have gone just a tad deeper.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150111_183314_zpshpoj6a1k.jpg)

Then I turned away.  I worked in reverse on the back side as before.  Here I'm zoomed back so you can see the tool post better.  Both the 4-jaw chuck and the tool post are very large for this 7x12 lathe.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150111_183831_zpsvrvogsue.jpg)

I mounted the part between centers using this tiny center and it worked fine.  I wasn't terribly happy with the finish I was getting on this hot rolled steel, but it was turning ok at least.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150111_204407_zpso9z8icfn.jpg)

I used the parting tool to clean up the shoulders.  It worked fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150111_210230_zpsnroo5mn2.jpg)

I thought about how to turn the angled part.  The plan showed an 8 degree angle overall.  I thought about adjusting my tailstock out of line so it would cut a taper, but it took so much work to get it aligned so I really didn't want to do that (until I add an adjustment screw to the tailstock).  I started moving the headstock end of the part until I realized that, duh, that wasn't going to work.  All I'd do is remove material from one side of the part.  Not exactly a taper.  So I finally decided to go with the compound.  I'm not sure why this wasn't the first thing to come to my head -- maybe because the angle was so small.  So I set it to 4 degrees from center.

You can also see I messed up my layout lines on the part.  If I recall I used the diameter as the radius.  I decided to actually scratch the circle, which turned out to be a good idea because it caught the mistake.  Note that I painted on layout dye to the diameter I am about to turn.  I thought it would make it easier for me to track what material I am removing.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_173928_zpspskxvchj.jpg)

Here I am turning it, using the compound to move the tool.  For each pass, I would back the cutter back beyond where the previous pass started, I'd crank in 5 thousandths on the cross slide, then I'd use the compound for another pass.  It worked fine.  Later on, I looked back at Stew's Dad & Lad's and found he did the same, except he used a 3 degree angle.  My 4 degree angle was ok, but if I were to do again I think I'd go with 3.  It feels a little bit flimsy on the ends.   Still not too happy with the finish.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_175046_zps5umxwkqk.jpg)

I flipped it around to do the other side, and then used my parting tool to clean up the ends.  I thought the little round bit looked nice, so I left it much like this.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_182738_zps5jmgy7lb.jpg)

Once it was cleaned up a bit, I pulled it from the lathe, trimmed the excess off the end with the bandsaw, and then off to the mill to flatten the edges properly.  This is where I was wishing I had done this up front.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_185831_zps2qb79la9.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_190342_zpszojqgx7u.jpg)

Next it was time to drill and tap holes for the brass bearing on the one end.  I had a scrap of steel that was fairly well matched to the part, so I used it to balance out the vice.  This gave me the idea to leverage it for clamping for a little added stability.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_200235_zpsqbcguwya.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_201259_zps36mekden.jpg)

I went with #2-56 threads so I tapped by hand.  I know it sounds odd not to guide it, but I don't have a special tapping guide and the mill is much too clumsy for this tap.  It worked fine, and in fact was quite easier than aluminum as I didn't have to worry so much about tearing out the fine threads.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_202615_zpsgkkvo1sf.jpg)

Next I drilled out the circular end.  This is partly why I needed to mill the edges flat.  I probably could have gotten away without doing that.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150113_204117_zpsbukbbsxl.jpg)

I made a couple filing buttons for the end out of 3/4 inch steel rod.  These were fairly big so I didn't need to tap them.  I experimented a little to allow them to rotate.  In later pictures you'll see I started using a longer bolt with two nuts jammed (I didn't have nylon this size).  I also used lock washers to let them be a little loose yet still stay nicely aligned.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150115_190118_zps4kxjnwpx.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150115_191347_zpsftnujpye.jpg)

Filing took a bit longer than previous work because there was a lot of steel to remove.  I used a rough file across and started by making flat areas as if I was making a hex shape.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150115_192715_zpsoku18g4c.jpg)

When I got real close I started using black sharpie marker to color it, then I'd file, and then I'd add more marker as needed.  This let me see when I was nicking into the buttons.  Much of the diameter was easy because I could file with the rotating buttons, but near the conrod side I couldn't do this.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150116_180305_zps1efoogj2.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150116_180811_zpsba3ktyzr.jpg)

Well, that's it for this post.  Next are the other little bits that form the connecting rod, and then a little overall cleanup.

Todd
Title: Re: Pottymill horizontal engine build
Post by: Stilldrillin on January 19, 2015, 08:51:36 AM
Nicely done. Nicely shown, Todd!  (http://www.picgifs.com/smileys/smileys-and-emoticons/applause/smileys-applause-242316.gif) (http://www.picgifs.com/smileys/)

David D
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 20, 2015, 02:19:50 AM
Completing the Connecting Rod

In the last post I finished making the main part of the connecting rod.  I continued to sand and tune it up.  I'd "paint" it with a black marker, and then sand away until it was finally getting to a nice match with the buttons.  I fine tuned it while watching the first two Hobbit movies, then took my kids to the last one at the theater.  (I'm having a lot of fun machining, but I'm not so crazy to bring it with me to the theater, though!  I've seen knitters go around that bend before :)).

Here's the main part for reference.  I need to create a bearing for the flat end, and insert a bearing in the round end.  I'll do them in that order.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150116_181123_zpsmj5xxi2c.jpg)

I first needed to make a little steel "holding" part to go on the end.  Bolts will start through this end, go through the split brass bearing I am about to make, and thread into the main part at the flat end.  I drilled clearance holes for my 2-56 "bolts" in the end of some of the same bar from which the main part was turned.  This part will be only 3mm thick, so I drilled 3mm deep.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_110443_zpsj4mpkfwu.jpg)

I chopped it off slightly long (~4mm) in my bandsaw.  I was VERY happy my new bandsaw could slice this accurately.  Here I have it flipped over and will mill it down to thickness.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_112534_zps1fmlrsg2.jpg)

I made light passes of 5 thousandths of an inch until the holes appeared.  The thickness of this part isn't so important, but it ended up at 3.07mm anyway.  Not bad for not measuring.  Note that I didn't clean up the other dimensions.  The top side was already milled flat, and I didn't really care about the other four sides because I plan to flatten them all together when they are bolted as an assembly.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_113138_zps94ezu7r0.jpg)

And the bolt holes line up.  Always a good sign.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_113636_zpst0eyoyid.jpg)

Next, it was time to make a split bearing out of brass.  The trouble was that I didn't have brass close to the size I needed (3/4" wide by 1/4" thick).  I need to add that to my wish list.  But I did have 2" wide brass, so I sliced off a bit.  The bearing is to be split, so I figure I'll make the two side by side.  The bearing is to be 12.7mm in total, so I cut this about 7mm to have a little extra to flatten it out.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_140601_zpsh1kij9te.jpg)

I roughed them to length on the lathe by parting off lengths that were close (not shown).  Here I am trimming it a little closer in size.  In the end, I will flatten them when bolted together so it's ok to be long.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_144153_zpsdpw0rbuc.jpg)

Next, I drilled for the bolt clearance holes.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_151743_zps9tglusa3.jpg)

I found they weren't quite the right thickness so I had to skim them again.  Not the best time to do it, but it worked out ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_152833_zpsj5mmcj79.jpg)

Here they are bolted up.  I carefully measured from end end of each brass part when I drilled the holes, so the two brass parts line up pretty good on one side.  I needed this as a "better than nothing" reference for skimming the sides flat.  Which I did.  I'm never quite sure when to insert paper in the vise, but this part wasn't perfectly even so it seemed it could use it.  It was bolted together so maybe this didn't matter so much.  And maybe I should have used it on both sides (I didn't).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_153549_zpsx1fpznqs.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_154100_zpsb2uljego.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_154510_zpsv5dmzxlm.jpg)

I decided not to skim the large flat areas.  They are very close and I thought sandpaper on a flat surface will go better.  The steel on the ends will act as filing buttons.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_154618_zpsg3jh1hrg.jpg)

Sanding worked pretty good.  This only took a couple minutes.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_154809_zpsrp6e9i4b.jpg)

Next, I used the round end to locate a useful position on the part (using a button made this even easier), and used that to locate the hole for the brass 60mm over.  I decided to drill and ream this hole to 0.251 inches.  I'll make the crankshaft from 0.250 inch rod.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_174147_zpseyrsb5du.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_174510_zpsifxyoo4b.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_175311_zpsmkxpntug.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_180115_zpsucmjjhq7.jpg)

Looking good.  Now it needs a bearing for the other end.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150118_180935_zpsjzx6adf8.jpg)



The Cross Slide Bearing

The trouble I expected to have with the cross slide bearing was to get a nice tight fit into the connecting rod, so I cooked up a scheme to get there.  I don't have a means to measure a hole precisely, but I can take the time to make test fits.  So I turned down some 1/2" brass rod to a close fit, and then turned down the tip to what I think will fit.  I used my parting tool for all this work.  You can see at the tip that it's turned down in two steps.  The step closest to the edge went too far.  I knew the hole was drilled 5/16" (0.312) so I went for 0.322 for my first attempt and found I went too far.  Go figure that it would be that far off!  So I moved inland and tested one thousandth by one thousandth until it just slipped on.  Each time it didn't fit, I would double check (of course!) and if it really was still too big, I would skim over the rest.  Once the part slipped on to this little bit on the end, I knew the rest of the brass was 1 thousandth over.  That's just what I wanted.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_182914_zpslssezmck.jpg)

Next I drilled it out by stepping a few bit sizes until I got to a D bit which fits the pin this bearing rides on.  I debated if I should drill it now or later, but opted to do it now while the part was perfectly centered.  Centering isn't critical, but since the bearing is so thin I thought it would be easy to see if it's off center.  In hindsight it didn't matter because you can't see the bearing anyway.  Sad really.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_184917_zpsss21g37q.jpg)

I tested the fit for the pin.  It's good as far as I can stick it in, anyway.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_185000_zpsz9kaz0we.jpg)

Finally I trimmed a bit from the end, but left just a little of the undersize brass as a guide for pressing it.  Then I parted it off to just a hair over length.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_185335_zpsegkplygf.jpg)

I had to file off the bit that remained from parting. This was easy enough, but I did it by hand.  I didn't want to risk bending it out of round in a vise.  A twist of a chamfering bit took off the last bit of it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_185443_zpsmgykqwlk.jpg)

Now it was time for pressing it in.  I don't have an arbor press, but I thought the vise would work fine.  It did.  It resisted a little -- but not much.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_185852_zpsz2carld3.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_185917_zpsaqpawvjf.jpg)

I need to sand it flush, and also found the inside hole changed diameter ever so slightly.  I was expecting that. The metal has to go somewhere.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_190127_zpsjk5po1yr.jpg)

But this was easy to fix.  I twisted in the D bit with my fingers and gave it a spin.  That's all it took to fix it up.  Must've been only a thousandth or so.  Dunno...remember I don't have a way to measure it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_190238_zpswvjpvz99.jpg)

I ended up with a very close fit.  I wasn't thinking about this when I was machining the the cross head.  But it ended up well by luck.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_190952_zpsqkkd4a3b.jpg)

And now the parts are fitting together nicely!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150119_190908_zpsiwl8qpbg.jpg)

I'm not positive where I'll go next.  I think it will be the cross head slide bar assembly.  Then I can also make the block that supports the engine and the base plate.

Todd
Title: Re: Pottymill horizontal engine build
Post by: vcutajar on January 20, 2015, 06:02:54 AM
Quietly following your progress Todd.  Keep it up.

Vince
Title: Re: Pottymill horizontal engine build
Post by: Jo on January 20, 2015, 09:24:16 AM
Nice Todd. Like you I put some sort of marker on the rod before I cut a taper so I can see what is happening :ThumbsUp:.

A second thing worth doing is take to tool to the small end and then back it out to the start of the cut. If you slip a feeler gauge behind the tool you can measure half of what you are about to turn off so you can check if the angle will cause the rod to become a bit thin before cutting metal and adjust accordingly ;).

Jo
Title: Re: Pottymill horizontal engine build
Post by: Roger B on January 20, 2015, 11:39:47 AM
Nice work  :ThumbsUp:  :ThumbsUp: Still following along  :popcorn:  :DrinkPint:
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on January 20, 2015, 12:36:28 PM
That turned out great Todd. Still following along here as well.  :popcorn:

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on January 26, 2015, 03:14:00 AM
I finally got back into the shop to make the four slide bar pillars.  Not much, but they took a while for me to make.

Slide Bar Pillar

There are four slide bar pillars that look like the following.  Since I'm building in imperial measurements, I decided to leave the larger radius as-is (16mm) and the smaller radius as 1/4 inch, which will match the slide bars.  I'll use 2-56 threads for the top, and 4-40 threads for the bottom.  Height gets adjusted later, but I wanted them to look as identical as I could get to the eye without spending gobs of time measuring.  So I was thinking about how I might automate this a bit since I was making a few of these.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap11_zpssgpixcmw.png)

I turned and faced some 3/4 inch bass rod.  I didn't have 5/16 inch rod which would have been nearly correct as-is.  In hindsight, I could have used 1/2" rod and the bases of these pillars would have been a bit smaller, but would have looked fine.  I had enough rod extending to make two at a time.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_163544_zps45i6f7mh.jpg)

I don't yet have a carriage stop, but after doing this job making one has drifted very high on my to-do list.  The smaller diameter of this pillar is 1/2 inch tall, so in this picture I have the carriage positioned without moving after the facing operation.  I clamped a bit of brass as my stop, and I spaced it with a bit of scrap 1/2 inch diameter rod.  It was a quick way to set the stop.  I wasn't too keen on placing a C clamp here, but it worked out ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_163708_zpsjccikto4.jpg)

I turned it down to 1/4 inch diameter using the stop for my starting point and letting it feed to the right.  This was backwards for my cutter, but it actually made nice chips and a nice finish.  I had to be careful with that C clamp handle which was pushed back a way for the picture.  Don't get that in the chuck jaws!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_164742_zpsy3wxlcqk.jpg)

Next I drilled and tapped the top with 2-56 threads.  I used the chuck jaws as a guide for the tap and it worked pretty good.  I spin these little taps by hand with my fingers.  If it gets stiff, I back it out, clean it up, and run it in again.  It looks like the tap is in the chuck, but it's only pressing up against it for guidance.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_173713_zpsyjeillts.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_174000_zpslenln9fr.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_185627_zpsilwtvewe.jpg)

I rounded over the edge next.  I decided to try to make a cutter for it, and it turned out pretty good.  I took a 1/4 inch hss blank, ground it on the corner edge of the grinder to get the internal radius, gave it a fairly generous clearance angle on the front edge (can't see in the picture), and gave it a clearance angle on the right that wasn't really needed.  I ran it in at the angle shown here, and then did a little fine adjustment pushing in with the cross slide.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_174608_zpsboewg1wq.jpg)

I came up with this arrangement for positioning the parting tool by using some outside calipers which were pre-set.  That's a parallel that's squeezed between the tailstock and the part.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150124_193959_zpsn3cdqstt.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150124_194211_zpsn7ezs9fy.jpg)

I flipped them around and faced them off.  I switched back to my little 3-jaw chuck for this.  Note that this particular part has already been drilled at the bottom.  On my first part I decided to drill all the way through for the 2-56 threads.  What I found was that the drill was slightly off by the time it came out the other end.  That meant the next part had a little dimple off-center as a starter for the next part. Not good.  It wasn't off much, but enough.  After this "education" I decided to drill partway, and then later drill in from the bottom.  I'll get to that below.  Right now I faced this one and then left the cutter in this position and ran it over the others so the bases would be the same thickness.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_192340_zpsnegmqoc1.jpg)

Here's how they looked after the first pass.  They were pretty close to a common thickness.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_193057_zpstapahlny.jpg)

I gave them all another pass to clean them up just a bit more.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_193756_zpsfqyvexx7.jpg)

Finally, I drilled for 4-40 threads into the bottom of each.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_194242_zpsigasb2by.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_194350_zpsprd7bjgq.jpg)

I tapped by hand the same as with the 2-56 threads.  For larger than 4-40 I've been chucking the tap in the tailstock and rotating the lathe chuck to do the work.  That seems a bit clumsy for these little ones and I was worried about stripping out the new threads.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_194759_zps2aelrazg.jpg)

Here they are holding up a parallel.  The one on the left was the first I made as I figured out how I was going to set the stop.  It came out a 12 thousandths shorter than the middle ones.  The two in the middle are identical height, and the last one I made on the right was 4 thousandths shorter than the middle ones.  Not too bad for almost no measuring.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150125_200102_zpsh5lclscj.jpg)

I'm not sure how I'll finally level them.  I could skim them with the mill after screwing them down, but I'll probably just end up doing a little filing where I need it.  Tolerances are probably a little loose.  I doubt the cross slide will care too much about a few thousandths, but I'll probably clean them up a little anyway.

That's it for now.  Thanks for looking!

Todd
Title: Re: Pottymill horizontal engine build
Post by: arnoldb on February 01, 2015, 01:04:03 PM
Good progress Todd  :ThumbsUp:

Kind regards, Arnold
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 04, 2015, 05:15:40 PM
I've been working a little off and on making some bits.  It's time for a report.

The Cross Head Slide Bar Assembly

There are two sets of slide bars, each of which is a pair of bars separated by a spacer.  These sit on top of the pillars that where shown in my last post.  The net is that I need to make four bars (two per side) and four spacers.  One of the spacers is special in that it is also a guide for the valve rod.  My thinking was similar as with the pillars -- what can I do for repeated cuts?  I do have a vise stop so it will get used here.

The bars and spacers are all 6.3mm (1/4") in size.  I started with the spacers and decided to make four, even though I only need three.  I drilled deep enough for two at a time.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150127_192612_zpsg4ecwgql.jpg)

I tried various means to precisely measure the length of the rod for parting it off.  Here I show a DI setup that worked ok, but not great.  I also tried dialing since I had the compound parallel to the lathe axis, but I found the dial markings are fairly meaningless.  They may be metric and I suppose I ought to figure that out.  The cross slide is very close to thousandths, so this surprised me.  If I had a carriage stop, I could have set it to match the face and then used a spacer to move it toward the headstock for each operation.  That's another vote for making a stop.  This is also another vote for a DRO...but that's going to have to wait.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150127_194741_zpsseal59cf.jpg)

In the end, I used the DI to get them close, and then I tidied them up one by one as shown here.  I got pretty close...one was off by 2 thousandths, but the others were exactly matching.  And I only needed three so this worked out.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150127_201107_zpsrpd0m7qi.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150127_211054_zpsatq0ogis.jpg)

Next, I needed to make a fourth spacer that is also a valve rod guide.  I decided to make it from the same 1/4" stock I'll use for the slide bars, but this will be a problem as the spacers need to be slightly larger (0.2mm or 8 thousandths).  I thought I'd try to mill a little spacer.  I was curious if this was possible, or if the mill would send it across the room.  I took some light passes on shim stock and was surprised it worked out ok.  I had it resting on a parallel and used a bit of rod to clamp it tight.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150129_201553_zpsjrbbfy83.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150129_203024_zpsjkrhyimc.jpg)

I tried a failed experiment to loctite it to the guide bar.  The idea was to have enough strength to drill the hole through this shim and the guide.  But I found loctite doesn't work that way.  It fell right off...only good for threads.  I thought about epoxy, but decided to drill it directly.  To my surprise, that worked!  I thought I took a pic of that, but I guess not.  I do show drilling the valve rod guide bar.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150129_203627_zpsyoi1bunh.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150130_175625_zps8jesvqnt.jpg)

Then I drilled the main cross slide guide bars.  These were cut slightly over length and I was able to use the stop I had set for the previous small guide bar.  I drilled one end only as the length wasn't correct yet.  I did this for all four bars.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150130_183751_zpsfitrlwib.jpg)

Next I used my X dial to position 62mm down the bar.  The vise stop stayed put.  I drilled all four bars like this.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150130_185408_zpsnleh3tl4.jpg)

And finally, I repositioned the stop to get a perfect 64mm length on the bars.  I did this in two passes.  The first pass matched the length of the shortest bar.  It was close enough that I could mill off the end in a single pass.  Then I milled one bar to 64mm using the dial.  The other three were done in a single pass at that dial position.  I took off maybe 5 or 6 thousandths to get here.  It was already very close.  In fact, it was pointless to "fix" the length as it isn't important, but I thought it was good practice for future projects.  I'm sure this is "machining 101" stuff.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150130_190230_zpseuel81nl.jpg)

Here's a family shot of the guide bars.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150130_191347_zpsfbonp5ht.jpg)

Next I had to drill the valve rod guide for the rod.  This guide turned out too short, but I kept going anyway.  I decided to drill and over-ream this since I had a 0.126 reamer (the valve rod I used is 0.125 inch).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150130_193243_zpsuhxn7spu.jpg)

Finally, here are the parts semi-assembled.  I need to make slides and thrust washers for the cross head, and I still need to make the supporting block for the cylinder.  It's resting on scrap bits right now.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150130_195359_zpsxajstff6.jpg)

Next up, I'll make the slides, cylinder support block, and a base.

Todd
Title: Re: Pottymill horizontal engine build
Post by: Perry on February 04, 2015, 05:33:18 PM
Very nice  :ThumbsUp:
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on February 04, 2015, 05:40:12 PM
That is starting to come together very nicely Todd... :popcorn:

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 05, 2015, 01:49:32 AM
Thanks all for watching :)  Here's a minor update from earlier.

I needed to make the slides for the cross slide.  It also looked like I needed to remake the little valve rod guide from the previous writeup, so I set about doing that here.  I observed that all three of these are identically sized.  I hadn't noticed that earlier, so I embarked on making three parts this time.

Since I was making a few, I could balance out the vise as I trimmed up the rough cut steel.  This is 1/4" square bar that I'm milling to 16mm length.  It's interesting I'm mixing measuring systems like that :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150131_102240_zpswqlirevt.jpg)

It was time to extend my vise stop for little parts like this.  I happened to have the correct threaded rod and it worked nice to trim the three parts to identical length.  Really, the length isn't critical, but at least I wanted the two slide bars to match.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150131_170901_zpsazvq8sne.jpg)

The cross head has 10-32 threads, so here I'm drilling for 10-32.  When I was done I noticed two things.  First, that hole is mighty big for the 1/4" slide.  Using 8-32 threads on the cross slide may have been a better choice.  I was thinking bigger is better, but I was pushing it here.   Second, that hole looks off center.  Dang.  But hey, I have a spare.  So much for remaking my valve rod guide, though.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150131_172926_zpse8nhxpkn.jpg)

Now I had paranoia going on, so I bothered to hit the next one with layout dye just to check my work.  This time it was dead on.  I'm not sure how I screwed up the previous, but I'm using the dials so maybe I got off by one turn.  The messed-up one on the left is really obvious in this photo.  Note that I threaded it anyway.  I checked it out on the cross head looking for any other trouble.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150201_095623_zpsqkcr3yem.jpg)

Here I finished up drilling and threading the second slide.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150201_101235_zpsvyzbqb8v.jpg)

Now we have a family shot, so to speak, that's semi-assembled for show.  The slides are installed on the cross head and move about in that space just fine.  Before trying to tune anything up, though, I really need to make the base to lock everything down.  Then I'll see where things need adjustment.  In order for that to happen, I need a real base for the cylinder.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150201_105609_zpsdh9caoj5.jpg)

The cylinder base is 16mm square aluminum.  I used 5/8" which is 5 thousandths short.  If the cylinder isn't high enough, I'll either need to shim it up, or I'll need to trim the pillars.  In a way this is good, because I can use a feeler gauge to measure the adjustment.  How's that for positive thinking?  Here I'm drilling the holes for attaching it.  I'll use 8-32 screws for this.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150201_123511_zpss3nku4li.jpg)

And now I recalled that I never did get around to drilling and tapping the attachment holes in the bottom of the cylinder.  I had to pull the cylinder assembly all to pieces and do it now.  One side of the cylinder is flat and the other round.  I placed the rounded side against the back (fixed) jaw of the vise and measured to the center from there.  The cylinder is 1.25 inch diameter so this was easy.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150201_143355_zps4hui6smm.jpg)

Now I have quite a "kit" of parts.  I told you I had to pull it apart!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150201_145041_zpsieitl3ij.jpg)

I needed a base, so I painted and marked up some 1/4" x 2" aluminum with layout dye and set some parts on for a sanity check.  Looks ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_182126_zpsbyr3y5jd.jpg)

Time to drill.  Dang, that hole looked mighty big.  I realized I drilled for a 10-32 screw and I was using 8-32.  Doh!  I went ahead and drilled the other, and I also checked with the screws I was going to use.  It doesn't matter...the screw won't slip through so it's ok.  In fact, I guess the one larger hole will give me a lot of wiggle room for adjustment, even though I'm sure I won't need it.  Just being positive again :).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_183111_zpsp2cbqdxm.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_183506_zpsaulbbmsb.jpg)

A test fit for sanity.  The block won't attach this way, but the screws are lined up which is what I wanted to know.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_183544_zpst1swjf56.jpg)

Next I drilled for the slide bar assemblies.  I had the aluminum hanging out of the vise so I didn't need to move it.  As it turns out, I decided to reset the dials for this anyway.  It was most important for the slide bars to be parallel to the base, so I did the two holes with a fixed Y setting, and then reset and did the other two holes.  The layout dye was a nice blood-pressure reducing addition.  They were landing perfectly.   This involved A LOT of spins of the dials!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_184807_zpsxahjy46o.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_185840_zpsgddoufh3.jpg)

Here it is all assembled and screwed down.  The cylinder height is good, partly because there is quite a bit of clearance between the slide bars.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_192524_zpsltyoysml.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_192603_zps37ifqcar.jpg)

And here's a close up.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150203_192547_zpsx7nwcprl.jpg)

Next I need to make thrust washers that sit between the cross head and cross head slide bars that I just made.  These will keep the head from wiggling side to side.  I also need to remake that valve guide that is front and center in the last picture.  Its position is good, but it's too tight, and there simply isn't enough material to drill it out further.

Oh, and I think the layout dye's got to go.  It just doesn't fit with the style of this engine :)

Todd
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on February 05, 2015, 07:37:30 AM
Looking very good Todd

 :ThumbsUp:

Stew
Title: Re: Pottymill horizontal engine build
Post by: Roger B on February 05, 2015, 11:03:04 AM
Looking good  :ThumbsUp:  :ThumbsUp:
Title: Re: Pottymill horizontal engine build
Post by: wagnmkr on February 05, 2015, 11:33:05 AM
This is looking quite good so far.

Well Done

Tom
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on February 05, 2015, 12:17:21 PM
Well done Todd. Are you going to try to lessen the clearance between the slide bars?

Bill
Title: Re: Pottymill horizontal engine build
Post by: Hans on February 05, 2015, 02:27:34 PM
Todd,

It is taking shape quite nicely.

As a beginner, I very much appreciate you taking the time to document and share the process. I learn more from studying these build threads than any other resource and the time it takes to upload photos along with the narrative is no small task.

Often the most helpful parts are the mis-steps followed by your description and implementation of a solution. Your willingness to include these in the story is appreciated.

Hans
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 05, 2015, 08:12:16 PM
Bill,

For sure I'll tighten up the slides a little when I remake the valve guide.  The problem is that the slides are 1/4" and so is the stock I'm using.  The little spacers are larger, but the valve guide is 1/4" also.  I'd like to avoid using the shim.  So that leaves a couple possibilities.  I could make the valve guide from thicker stock, which is my current plan, or I could slightly skim off the slides so they have some clearance.  This is only 5-8 thousandths so that's probably reasonable.  If I had used an 8-32 thread on the cross slide I'd have much more material for such an adjustment.  BTW, I have thought about running those 10-32 threads down to 8-32.  Since they are the same TPI, I'm guessing that will work, but I've never done that before.  I'd have to re-make the slides if I did this so it isn't top on my list.

Hans,

Thanks for the feedback!  I've been wondering how much detail to include as I'm sure there are yawns from many on the forum due to the great volume of pictures.  But I found this level to be VERY useful in my early days, which weren't that long ago.  I recall re-watching Jose Rodriguez videos after I had spent a little time in the shop, and when I did this I noticed many many things that I hadn't seen on the first pass.  Mainly how to deal with mistakes, as you say, but also how to setup things.  What side of the mill do you work on, what angle do you put the compound and/or cutter at, etc.  I still don't have answers for all that, but I found it helped seeing what others did.  I figure even if what I was looking at wasn't a perfect setup, it was still a reasonable setup since it worked for "that guy." :)  The thing I need to remember to do once in a while is back up and get a wider view shot so you can see setups.

BTW, if you follow any of my pictures over to photobucket you'll find I have many more pictures that I'm not showing here.  Feel free to do that, especially if you come back to this thread some day and build this particular engine.  I've been taking pictures with my Nexus 5 mobile phone.  It does an excellent job getting focus tight in spaces, and it's handy right there in my pocket.  I sometimes need to wipe the lens on my shirt, but that's about it.  No tripods, no extra gear.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on February 06, 2015, 12:46:45 AM
Hi Todd, guess I misunderstood, I thought you meant there was too much clearance between the slides and the slide bars. It sounds like you are wanting more clearance now rather than less. Still watching and following along with interest.

Bill
Title: Re: Pottymill horizontal engine build
Post by: rodw on February 06, 2015, 04:08:37 AM
Todd, this is an awesome build (and Instruction manual) I've been following along for a while. I don't have a lot of spare time right now and I've been getting withdrawal symptoms as I have not been in my shed for weeks. I'm very keen to attempt this build. I think a novice like me (with one simple engine under his belt) could do this by following this howto thread. I've been looking round for some metric plans so it fits the bill perfectly.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 06, 2015, 09:46:17 PM
Bill,

Your original understanding was correct.  I must've worded my response poorly.  It does have too much clearance right now.  Well, really I'm sure it would be fine, but I'd like to tighten it up a bit.  I hope to get some time to tune it up yet today.

The real trouble is that I'm trying to make the slides and the valve guide from the same stock.  The valve guide acts as a spacer, so either I need to make it thicker (e.g. using a shim or thicker stock), or I need to skim the slides to make them a little thinner.  Maybe I should consider skimming a few thousandths even though that 10-32 screw hole is mighty close to the edges on the slides.

I could keep the shim and skim the new valve guide (I'm re-making that, regardless) thinner.  That possibility just occurred to me now.

Todd
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on February 07, 2015, 07:45:49 AM
Bill,

Your original understanding was correct.  I must've worded my response poorly.  It does have too much clearance right now.  Well, really I'm sure it would be fine, but I'd like to tighten it up a bit.  I hope to get some time to tune it up yet today.

The real trouble is that I'm trying to make the slides and the valve guide from the same stock.  The valve guide acts as a spacer, so either I need to make it thicker (e.g. using a shim or thicker stock), or I need to skim the slides to make them a little thinner.  Maybe I should consider skimming a few thousandths even though that 10-32 screw hole is mighty close to the edges on the slides.

I could keep the shim and skim the new valve guide (I'm re-making that, regardless) thinner.  That possibility just occurred to me now.

Todd

Hi Todd:- I made the slides and the guide out of the same size bar also, I simply shimmed the guide using a piece of kitchen baking foil folded over a few times to get a reasonable thickness. As an aside there have been a few of these engines made that run well without the valve guide, so you have that option also.

Keep up the good work

Stew
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 07, 2015, 04:16:17 PM
Finishing the Cross Head Slide Assembly

I decided I'd try skimming down the slides rather than shim up the spacers.  Here's how that went.

First I had to re-make the valve guide.  It acts as a spacer (the small hole) and a guide for the valve rod (the large hole).  Sorry about the blurry pic...looks like the back of the vise got in focus.  But you get the idea.  The previous part was a little too short and the large hole was just about cutting through the end.  The valve rod is 0.125 inch, so I drilled with a #29 (0.136) for some extra clearance.  Previously I reamed to 0.126 and there was no way it was going to slide.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_190738_zpsmp0yp7id.jpg)

Next I skimmed the spacers all to 0.250 inch.  In the vise you'll see the old valve guide on the right, the new one on the left, and four spacers in the middle.  I only needed three spacers, but I made four for testing and in case one jumped ship (which always happens to me).  My working theory was that I'd slowly run the mill down until I could hear it barely skimming the old guide on the right, then I'd skim across.  I actually made 3 passes going a little closer each time.  Note the folded paper was required.  I tried without and the first round spacer started spinning!  There is a single parallel holding them up on the back side.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_191652_zpsrmk4lwvy.jpg)

Now that my spacers are a matched set, any irregularity must be either the brass pillars, or the base plate, or the parallelism of the cylinder to the base.  Nice to rule things out.  In the end I skimmed off an extra thousandth.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_192224_zpsxhww74en.jpg)

I tried bolting down the guides, but of course they pinched the slides so it couldn't move.  Next was time to skim a few thousandths off the slides.  I took 4 thousandths off the top of the slides and then did a test fit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_193225_zpsrqp50vah.jpg)

Here's the test fit.  I managed to turn on my brain and think about using feeler gauges to see where I was at.  3 thousandths at the bottom, and snug on the top.   The cylinder is riding slightly high because it measured consistently down the length.  At least that gave me some confidence the piston rod wasn't going uphill.  This means I need to skim more off the top of the slides, and also means I need to keep track of up vs. down when I install them.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_195222_zpsomzjjxo9.jpg)

While I was at it, I had a look at how the valve guide was doing.  It's riding a little high as can sort-of be seen in this photo.  Rather than try to elongate the hole, I decided to drill it larger until it fit all around.  Worse case I'll need to make that part a third time and shift the hole down a bit.  If that's the case, I can do the math based on the enlarged hole size that worked.  So I may as well drill it out.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_200823_zpswykh2f2a.jpg)

Here we are, two drill sizes larger.  This was a #27 (0.144).  I'll leave it like this for now.  If it runs sloppy, I'll need to account for needing to expand the radius by 10 thousandths.  That is, shift the center down 10 thousandths.  All in all, I don't think this is so bad considering I didn't adjust the cylinder base.  Remember it was undersized by 5 thousands to start (16mm vs 0.625 inch), so half the problem came from that.  The valve chest might shift a bit if I unbolt it as well.  So  I'm leaving it for now.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_200952_zpskxbovdsp.jpg)

Next is finally time to make those thrust washers.  I measured with calipers and found they needed to be roughly 0.125 inch.   Since they are so small, I decided to make a pair and see how they fit using the feeler gauge again.  I'll remake them to fit correctly.  So face and drill some 3/8 inch brass rod (~10mm).  I used a D drill initially but had to change to 0.250 to get a slip fit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_202948_zpsfrrxijz6.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_203340_zpscb7ymdok.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_203623_zpsorbacn9q.jpg)

Here it is.  Not bad :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_204519_zpsjkt5ekvl.jpg)

And here they are on the cross head.  Brass looks nice in there.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150206_210615_zpscwbapehe.jpg)

With feelers I found one side needs to be 0.008 thicker and the other closer to 0.018.  So I made new ones.  Here's a new one on the far side that's now 0.130.  The slide is aligned with the guide rail, but I need to screw down the rails to get an accurate reading.  But it's easy to see what's going on with it partially disassembled.  Note the close side washer is pretty far off yet.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_090244_zpsthkwh8oh.jpg)

Here the close side washer is also replaced.  I ended up at about 0.140 for this one.  Things are still a bit adjustable as the guides can slip around a little when I loosen the bolts.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_091925_zpsih2hk6pc.jpg)

And here it is from a nice side angle.  I'm still thinking about some bling to go around the exhaust holes.  Recall the valve chest got drilled upside down and my air inlet is on the bottom.  That worked out ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_092016_zpsazb0tta3.jpg)

Now I think I'll turn to the crankshaft and bearings.  I can mount the bearing stands on the base and finally wipe off that ugly blue :).  The flywheel remains as well as the eccentric mechanism to operate the value.

I'm thinking about what to do for a wood base for the engine, but I'll wait until I have the crank and flywheel done. The flywheel will hang low so I'll need to account for that.

Todd
Title: Re: Pottymill horizontal engine build
Post by: smfr on February 07, 2015, 04:45:22 PM
Nice write-up, Todd. I feel we often "sweep under the rug" the tricky fitting and finishing part of engine building here, where you have to shim a few thous here, and take off a thou or two over there, and it's nice to see it described in detail. It does take a certain mindset to figure out all the alignment issues.

Simon
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on February 07, 2015, 09:30:37 PM
Glad you got it all sorted Todd and it looks great too!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 11, 2015, 08:40:48 PM
Here's another installment in the pottymill horizontal engine building saga.  I have loads of pictures this time, so butter up the popcorn and enjoy the slide show.  Be thankful you aren't about to view one of my vacations :)

The Crankshaft

The crankshaft is built up as an assembly of several components.  I looked at it for a bit and, perhaps in a moment of foolishness, I decided to go out of my comfort zone and build it out of a solid hunk of cold rolled (bright) steel.   I happened to have a bit of the stuff that was nearly perfect in size.  I thought my little Harbor Freight 7x12 lathe was up to the job.  Those intermittent cuts give me the heebie-jeebies so this effort might rid me of such worries.

I started by inking it out so I could keep my bearings as I turn it.  Later on I etched in some big X's over the areas that would be removed.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_162002_zpsmemi5nkz.jpg)

The CRS was a bit wide so I used my bandsaw to chop off the excess.  It gave me a bit for another project.  I need to build up my metal supply so I have pieces closer in size when I do this stuff, but the cutting went good and didn't waste much metal.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_162454_zpsmdsqgvuf.jpg)

Next I drilled for centers.   This bar is 0.5 inch thick and it's sitting on a 0.5 inch center that's laying flat so I used a little paper to let it snug up in the vise.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_165224_zpscatlbxvm.jpg)

I placed it between centers...but now was at a little bit of a loss how to drive it.  I could have created some kind of dog that would clamp to this surface.  In fact, a bunch will get cut away, so I could have drilled/tapped and installed a stud of some kind, too.  Instead I decided I could chuck it in the 4-jaw and use the tailstock as a support.    Note that my bandsaw cut fairly straight along the top edge.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_170503_zpspb1ig9wd.jpg)

In order to chuck it, I need both sides flat and parallel.  So I cleaned them up over on the mill.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_171237_zpsbpuaf61n.jpg)

I indicated and adjusted, indicated and adjusted, ... and got nowhere after quite a bit of time fiddling around.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_173252_zps5kqke4y7.jpg)

The problem was that when I'd run it, I'd notice the tailstock wiggling.  It was clearly out of alignment, but I was damned to see how.  I checked it along the length and it was perfect.   Later I realized the root cause of the problem was that the center holes on the end were ever so slightly off the center line of the bar.  I skimmed over the crank web to round the ends, but by the time I was done I decided I'd need a different approach.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_173657_zpselpy3uh8.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_190627_zpsuoodyyrg.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_192009_zpsletaqmlk.jpg)

So I turned a bigger stubby temporary center so I could embed the crankshaft bar into the chuck in a manner similar to the connecting rod a few weeks earlier.   The alternative would have been to make a general purpose dog to clamp onto the bar.   Either way I'd end up with a little "tool" for the next job.  So here goes...
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_194914_zps6dmakvgm.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_200130_zps2krrk2rh.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_200748_zpsq8rrdmou.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_200948_zpsqxpveidv.jpg)

Now I'm able to turn on centers.  I know the little stubby center isn't perfect since I had to move it into the chuck, but it should be pretty darn close.  Here I'm using the parting tool to start opening up the web.   It wasn't going so well.  The bar really pounded on my parting tool.  I needed a better way to clear out the metal.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_201651_zps8cbbknbk.jpg)

Well, duh.  Time to drill out a bunch.  I was a little sloppy, but it took a pile of metal out fast.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_203242_zpsih3gcvxb.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_203710_zpslqrjpnua.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_204109_zpsg5k45rky.jpg)

Now back to the lathe.  It was going ok, but I got to the point where I needed to extend the parting tool further.  This wasn't going to work.  The tool was just too wiggly being extended so far and this being such a nasty intermittent cut.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150207_205125_zpsln9diieh.jpg)

I thought a new cutter might be in order.  For giggles, I placed a 5/16 inch HSS blank in my toolholder.  It came with a pre-made 10 degree relief angle on the end.  I honed it a little, but didn't grind any other relief angles.  I wanted to see if it might work, first.  It actually worked crazy-good.  Go figure.  It's really a big fat parting tool.  I had to go slow, but it worked.  And remember much of the material was drilled out already.  The end had a bit of an angle, but that was ok for this rough shaping.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_130316_zpsuhqsda5g.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_131510_zpsa53xxcfh.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_132228_zpswfsfo3jm.jpg)

To remove the taper, I went back to my parting tool for some very light cuts.  It was now that I carefully turned it down to size.  I did some test fits with the connecting rod and repeated until it was just right.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_133808_zpslxzyd8ag.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_135501_zpshdvnd2n0.jpg)

And there it is...half way done.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_140505_zps1m6inogl.jpg)

Clearly I need to collect more ways to drive work on centers as this was the main problem today.  Once I got that figured out, and figured out what cutter to use, my little lathe handled the intermittent cuts for this "deep" (14mm) web just fine.

Stay tuned for the next part where this turns into something that actually looks like a crankshaft.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 12, 2015, 04:54:26 PM
The Crankshaft, continued.

Today's installment is mainly a slide show.  I took lots of pretty pictures so you can see the block of metal transform into a crankshaft.

Fortunately I have a metal cutting bandsaw which made quick work of chopping off the extra material.  It's already starting to look like a crankshaft even though it's a bit square-ish.  Note that I scribed X's so I'd have half-a-chance of chopping off the right bits.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_141425_zpsbudyhfbr.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_142059_zpssozpbqev.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_142658_zpsciiljvaw.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_142750_zps1goslalk.jpg)

Now the square shaft is small enough for my lathe dogs to fit without trouble.  At some point I took out the lathe dog's pin because the socket head screw worked good enough.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_171013_zpsok3aslhj.jpg)

I cleaned up the outside edges of the webs first.  This is a big intermittent cut and I thought it best to get most of it done while the shaft was still very thick.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150208_172346_zpsfv5ylxx1.jpg)

Next I started turning down the shaft.  I switched to a tough carbide cutter.   It worked good, but at some point it started interfering with the live center.  While it fit, I was able to cut about 0.050 inch per pass.  That was quite a bit for an intermittent cut on this little lathe.  It took a few passes to get to the point in the picture.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_185147_zpsaeifpc08.jpg)

I switched to an HSS cutter and continued making heavy cuts.  I think I was doing 0.030 inch per pass here, so the finish was a bit rough.  I was spraying with WD40 and it smoked a bit.  No fires, though :)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_191001_zps0tjoxars.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_192016_zpsqyedb8td.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_192218_zps8v5pqbu2.jpg)

I got to within 0.030 of final diameter and switched sides.  Back to the carbide cutter.  I was using the autofeed geared for the finest passes I could get.  That's 1/256 inch per turn on this lathe.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_192544_zpsnqtvsewg.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_193622_zpsxrmpzp7e.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_193902_zpswpzamemd.jpg)

Now I've switched back to HSS.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_194628_zpsv8megann.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_195322_zpsb9aq7wxo.jpg)

And just a little cleaning on the web is needed...
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_195636_zpstkcrqv2w.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_195934_zpsiqcjrydi.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_200749_zpsmgwb4fy8.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_202138_zpscmfscsea.jpg)

And now I switched sides to do a "final" pass.  This isn't really final, though.  I'm leaving it with 10 thousandths extra.  When I make the bearings I'll adjust the crankshaft to fit the bearings rather than the other way around.  I think that will be easier for me.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_202404_zpsqc9elabl.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_202955_zpsx0znublk.jpg)

And here it is.  The finish could be a bit better, but I'll fix that with lighter passes to fit the bearings.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_203132_zps7sj0yivo.jpg)

It fits the engine nicely too.  Remember I did take time to get the connecting rod fitting correctly.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150210_203426_zpszjfzgw1y.jpg)

It's still amazing to me that a part like that can pop out of a bar of steel.  And really it wasn't difficult.  I'm happy I took this route for the part.

Next up, the bearings and bearing stands to hold this crankshaft.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on February 12, 2015, 06:52:32 PM
Very well done Todd and an excellent write up for those wishing to make a similar crankshaft!! You are getting closer to a runner by the day now :)

Bill
Title: Re: Pottymill horizontal engine build
Post by: Roger B on February 12, 2015, 07:06:00 PM
Good work on the crankshaft  :praise2:  :praise2: The headstock centre on the Minilathes does seem to stick out a long way  ::) Like you I found it best to saw/drill as much away as possible before starting to turn. When I was turning the crank shaft for my horizontal engine I screwed a block between the webs to take the thrust from the centres. The holes will then be used to fix the balance weights.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 12, 2015, 10:08:25 PM
Good work on the crankshaft  :praise2:  :praise2: The headstock centre on the Minilathes does seem to stick out a long way 

Yeah, though I think it's a matter of scale.  The center is fixed size and the lathe is tiny :).

I'd love to find a shorter center, but lately I've been thinking about making some kind of faceplate that can bolt on, take some of the horizontal space, but most importantly it could provide additional places to mount driving pins closer to the centerline.  I also need to make up some driving apparatus like you've created.  That looks really handy to have in the toolbox.

Once this engine is done, I'm going to go back to tool building mode so I have these for next time around.

Todd
Title: Re: Pottymill horizontal engine build
Post by: Dave Otto on February 13, 2015, 01:14:18 AM
Hi Todd

Kudos for making a one piece crankshaft and it turned out real nice too!

One thing you might want to file away for next time is to put some material between the cheeks when turning the main shaft portions; this way the load from the center is transmitted through the extra piece and onto the other center, and not flexing the crank through the throw.

There are many way to do this but here is a picture of how I did it when I made the crank for my Pacific engine.

(http://i1236.photobucket.com/albums/ff451/idahoan_1960/Pacific%20Vapor%20Engine/Crankshaft_19_zps2f1c1546.jpg) (http://s1236.photobucket.com/user/idahoan_1960/media/Pacific%20Vapor%20Engine/Crankshaft_19_zps2f1c1546.jpg.html)

I have been enjoying following along with your build and enjoying your progress.

Dave
Title: Re: Pottymill horizontal engine build
Post by: Roger B on February 13, 2015, 07:54:48 AM
Hi Todd,

I am using the standard minilathe faceplate (mine cost around 20 British Pounds) and a small drilling vice as the driver (I don't have any driving dogs). I would recommend buying a faceplate. I am sure the US members can recommend suitable sources. I would also recommend some form of Keats angle plate. They are excellent for stretching small lathes to the limit. I have attached a couple of pictures of the ones I have. The simple one fits nicely on the minilathe faceplate but was too large for my Hobbymat.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 13, 2015, 07:14:46 PM
Dave,  I hadn't thought about the fact that squeezing the crankshaft could deform it -- or at least throw it out of alignment.  Nice tip, and maybe I'll try to setup something like that when I do the final turning of the crankshaft.  I don't expect trouble, but it wouldn't hurt to try it either.

Roger, thanks for the pointers.  Maybe I'm due to buy a faceplate from littlemachineshop.  I know they have one that will work for me.  I can always drill/tap for a driving pin that's close to the center, provided it isn't hardened.   I'm not sure I've ever looked at drilling vises.  That's something for me to check.  Thanks!

Todd
Title: Re: Pottymill horizontal engine build
Post by: Roger B on February 13, 2015, 08:44:36 PM
My faceplate was a nice piece of cast iron. I had no trouble in drilling and tapping a couple of holes for the Keats angle plate.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 22, 2015, 07:47:31 PM
It's been a while since the last update.

The Bearing Stands

The bearing stands for the crankshaft are fairly straightforward.  Here's the plan.  I decided I wanted to press in the bearing, so I decided to go with cold rolled (bright) steel.  I suppose aluminum would have worked, too, but I had the steel handy.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/pottymill-snap12_zpsuc8irep8.png)

I squared up the stands from 3/8" x 1-1/2" steel.  This was a bit thicker than the 8mm from the print, so I made some notes to make the bearings slightly thicker and to be careful fitting them to the base so the crank had some clearance.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150212_194244_zps8ecy8jfx.jpg)

It seemed like it might be smart to work with these blocks while they were still full width, so I drilled the holes next.  These are the clearance holes that will allow bolting it to the base.  I drilled them a bit extra deep so when I mill off the sides they will be exposed.  I found the edge on the left of each block and marked that spot so I could keep them oriented for other operations.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150212_202854_zpsfidq1twe.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150212_203834_zpskggjv82t.jpg)

Next I drilled for the bearing.   The plan called for 14mm diameter so I decided to use 9/16 inch.  As I started drilling with this center drill I realized I could have set this up better.  I should have turned the base against the fixed vise and drilled from that orientation to guarantee the height of the bearings was identical across both.  Instead I had to make another note to check this before I finished so I didn't need to find it the hard way when the engine was assembled.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150216_205525_zpsxwhxv4mz.jpg)

I drilled with a 1/2 inch and realized I was stuck.  I have some misc bits bigger than 1/2 inch, but not 9/16.  Doh!  Time to make an Enco order.  Fortunately bits like this were on sale, and free shipping.  So I ordered a 17/32 also.  Note here that when I drilled with 1/2 inch I had to use a collet to hold the drill.  My mill isn't big enough for the bit to fit with a chuck installed.  Maybe I should hunt down some stubby bits.  I did procure some screw machine drill bits for this purpose, but my set isn't this big.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150216_210256_zpsohn6skij.jpg)

Lucky for me, Enco's warehouse is only 2 days away (really only 1 day, plus a day for Enco to pack it up), so this wasn't a big loss of time.  I left the bearing stand on the mill, and when the bits arrived I finished drilling it out.  I used 7/32 followed by 9/16 in the hopes the hole would be a bit more accurate.  The new bits worked like a champ.  Nice and sharp.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150219_194239_zpsoicxf5rl.jpg)

I double checked the heights and found they were ever so slightly off, so I machined the bases together so the bearings will be even.  They were 2-3 thousandths off.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150219_200544_zpsmtvxs8se.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150219_200649_zpsqzdszkfd.jpg)

It was finally time to shape the sides of the supports.  I marked using layout dye so I could see what's going on and started with my 1/2 inch roughing end mill.  This worked pretty good and allowed me to take 31 thousandths off at a time (1/2 turn of the dial).  This is a lot for this little mill.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150219_201757_zpsrxqbumhj.jpg)

I switched to a 3/16 end mill, and then to a 1/8 inch.  I was thinking the little curve it would leave behind would be spiffy, and didn't think it would interfere with the bolt that was going to hold it down.  At this point I was using the dials to track where I was.  I didn't go so far as using an edge finder, though.  Instead, I had calculated how much I planned to remove from this 1.5 inch wide bar.  So I'd measure with calipers, find the edge by carefully running the running end mill up to it, set the dial at zero, and then proceed to remove as much as I thought needed to be removed.  This was just decorative so I could take extra as long as I was fairly consistent.  I got down to 2 thousandths remaining, and took the rest from zeroed dials.  That is, I turned X 2 thou extra and made the pass down in Y until I approached my Y dial's zero mark, went 2 thou past, and then pulled back on X to finish.  It worked pretty good.  Not perfect, but good.  I abandoned the 3/16 mill for the later cuts.  The roughing 1/2 mill and 1/8 mill worked fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150220_202136_zpszvbygw1n.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150220_203340_zps1xfuzbag.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150220_205051_zpsv2rkbngp.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_102434_zpsak4rxek4.jpg)

I worked the other side of the stands on the other side of the vise.  Then I didn't need to redraw layout dye on the back side.  It was handy having both on the vise like this, not only to balance the vise, but to allow me to double check with calipers that they were both equal as I worked.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_104403_zpsvyhjov3e.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_105916_zps0zekox9r.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_112123_zpsjfpgievb.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_113037_zpsdgtgzc46.jpg)

And there are the bearing stands.  I'll need to do a little filing to clean them up.  The plan also calls for a gentle curve at the top.  I could round over the edges, or I could setup the rotary table.  But for now they can stay straight.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_113123_zps3ifdohsm.jpg)

In the next installments I'll make the bearings and press them in place.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on February 22, 2015, 08:00:35 PM
Two more parts done and they look good. Nice to see an update on this one...it really is a nice looking engine!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 23, 2015, 12:25:43 AM
Thanks Bill....and I made a bit more progress....

The Bearings

The bearings are brass and as I mentioned in the last post, I hoped to press fit them rather than loctite them in place.  I have no real reason, other than I find it a bit of a challenge considering I have no tool to directly measure the fit.  So my plan was similar to what I've done before.  I'll turn down some brass until it's close, but for certain too large, and then I'll turn a bit on the end, maybe 1mm or so, and check the fit with the bearing stand.  If it doesn't fit, I'll finish turning at that depth and then I'll repeat with another step down.  I'd drop to doing this 1 or 2 thousandth at a time when I think I'm really close.

The working theory is that once I have a fit on this 1mm end, I'll face off that bit, and the rest which is untouched from the previous pass must be +1 or 2 thousandths over.  Close enough for pressing.  Well, that's the theory.

So here we go.  Face off and turn down some 5/8 inch brass rod.  Recall I drilled the stands for 9/16 so I have 1/16 to go.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_115936_zps74oqmbsw.jpg)

I'm showing my first test fit.  I turned more than 1mm for emphasis in this photo, knowing full well it's still a long way from fitting.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_134137_zpsyxtvesua.jpg)

After numerous passes I finally got my first "fit."  So the bit on the end is too small, but the rest should be fine for a press fit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_135630_zpsfclkixdy.jpg)

Now it's time to drill it out.  The crankshaft will end up at 5/16 or so.  Recall I left it oversize.  I'll drill the bearings to 1/4 inch now.  Later I will drill and ream them together to final size to make sure I have a matched set.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_140439_zps4uxywtrg.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_140701_zpss1cd4ydm.jpg)

Next part it off slightly wider than the bearing stand.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_141543_zpsw90lh8yu.jpg)

Now, time to press it.  I don't have an arbor press, but my vise will work just fine.  The bearing is thicker than the stand so I can only press it in so far.  Note how the stand is shaving a bit off the bearing.  Hope that's ok.  It sure was cutting it easily :).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_142548_zpsfsn5jwxr.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_142618_zpspv6lyvql.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_142643_zpst59wwgm5.jpg)

I brushed off the strands that were sliced off by the stand, placed some shims behind it, and gave it a bit more of a press.  This didn't completely center it, but got it close enough for me.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_142855_zpsxd5kdpx9.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_142936_zpsoyppuuqo.jpg)

I repeated for the second bearing, and now I have two stands with bearings, but the bearings are only 1/4 inch.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_144722_zpsbx2xrmhj.jpg)

Before drilling the bearings I marked out positions for them on the engine base.  In hindsight, perhaps I should have done this after I finished the bearings and turned down the crankshaft to fit.  But here I was thinking it might be interesting to attach the bearings to the engine base and drill them together for perfect alignment for the shaft.  Here I have marked the position and I'm checking that the crank will fit.  Looks tight but ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_162058_zpsjxl9bscz.jpg)

I drilled and tapped the four holes for the stands.  I could have run bolts through the base, but thought it would be convenient if they were tapped instead.  I had barely enough room on the mill to do this with the engine parts so close by.  The sad thing is that I dismantled them soon after anyway.  Oh well.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_170255_zpszjl4jcrr.jpg)

I used some 1/4 inch rod wrapped in paper to align them as best as I could.  The clearance holes in the stand were mighty tight so there wasn't much wiggle room.  I thought it's interesting how much slop those 1/4 inch holes had.  That rod was a little loose with the paper.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_171651_zps8wfovw2n.jpg)

I tried clamping the engine on its side so I could drill through both bearings in place.  I even jigged up a rod to hold them solid, but found that my mill simply doesn't have the Z space for doing this with large drill bits that don't fit collets that I own :(.  I even tinkered around with the thought of somehow bolting it to my carriage on the lathe and using it as a large horizontal drill.  But bolting would be tricky with no means to adjust vertically.  I decided instead to stack the stands as shown here.  The main thing was knowing the mounting holes would align, and thankfully I had marked the orientation with sharpie marker so all I had to do was align them on the end facing you in the photo.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_200507_zpsyvuwsstl.jpg)

I aligned the mill by using a drill bit dropped into the 1/4 inch hole already drilled in the bearings.   I found it interesting that the best fit I had was a "H" drill bit which is 0.266 inch.  What a sloppy hole!  Ok, I did drill it in one pass without smaller drills ahead of it...but still.   Good reminder that drill bits aren't that accurate.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_200601_zps4sittj9h.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_200744_zpseuejzxqj.jpg)

I drilled it out by stepping up to an N bit (0.302) and then I reamed with a 0.3135 "over" reamer.  I was planning for the shaft to be 0.3125 (5/16").  It isn't too big a deal for this to be exact because I'd be turning down the crankshaft to fit it, but I thought it was nice to know exactly what I'm shooting for as I was doing that.  With the reamer I was pretty sure it was going to be 0.3135.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_201326_zps0kiwatdx.jpg)

Note that my reamer is all the way out of the bearing.  That is, it just barely fits in the Z space of my mill.  Lucky me.  The finish could have been a little better.  Maybe N wasn't close enough...but I didn't have a better bit without going all the way to 5/16.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_201534_zpsf2dzrrx0.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_201601_zpsmqcxvv79.jpg)

In the next installment I'll turn down the crankshaft to fit and get a family shot of these new parts.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on February 23, 2015, 12:47:16 AM
Nice work on the bearings Todd. I don't think you'll be needing the Loctite to keep them in though...looks like you got a tight press fit...they should be there forever :)

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on February 23, 2015, 12:49:23 AM
Fitting the Crankshaft

In the last post I finished the bearings which were reamed to 0.3135 (1 thou over 5/16).  The last I did anything with the crankshaft it was at around 0.320.  So now is the time to clean it up and make things fit.

I setup the lathe for turning between centers because I was going to remove the crank frequently for test fits.  I used a micrometer also to check, but I was depending more on test fits when I got down to that last thousandth.   I followed Dave's advice from back in post #76 to add some support for the crank so I didn't bend it accidentally with the centers.  A 3/8 inch bolt fit nearly perfect.  I wrapped with a bit of paper to get it snug.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_204015_zpsrdqm7dbx.jpg)

Here's a shot from further back so you can see the overall setup better.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150221_204022_zpssvwkuj0z.jpg)

All I had to do was turn it down to near 0.314 and then start test fitting.   I went down to 0.318 and tried from there and went 2 thousandths per pass until I got a fit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150222_135714_zps5fywrtlr.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150222_141525_zpsuk42vo2m.jpg)

I thought I had a nice, albeit a bit tight, fit at 0.312 but the bugger got stuck when I quit turning it around!  Maybe it cooled or something.  Anyway, way too tight...it was entertaining to pull it off.   I took one more pass and brought it down to 0.311 and then it fit very nice.  I felt pretty good since that's pretty much where it should be, as far as I know.  Then it was time to turn it around and work the other side.  I wrote down the dial setting and didn't mess with anything (other than cranking back) so I knew where I should end up.  But I did test fits anyway.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150222_142421_zpsc6w63eic.jpg)

When test fitting I found the crank was a little tight.  I noticed that one side of the web was angled ever so slightly out, so I fixed that now.  I did the same on the other side to get a nice sharp shoulder.  This was enough to get a nice fit.  In my haste, I forgot to re-install the bolt to protect the web.  Doh!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150222_153306_zpsrrvgop1m.jpg)

Some re-assembly required.  Note that I cleaned up the base.  I have a lot of sanding and polishing to do and now is a good time to make a little progress when things are apart.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150222_154219_zpsyrsl7wvu.jpg)

It's starting to look like a real engine now!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150222_154639_zpsib5onock.jpg)

And here's the other side.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150222_154659_zpsjlmm0ldb.jpg)

I can crank the engine now, but it's pretty stiff.  I've checked it over and I don't think anything is binding.  There's just a bunch of friction.  I'm not going to fuss with it now because sand/polishing will loosen it up some, and I can always resort to simichrome to loosen it up, too.

Thanks for looking in!  I'll probably do the flywheel next.  I have a 4 inch diameter steel blank for that and I need to think about what I want to do for it.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on February 23, 2015, 12:55:39 AM
Very nice!!! The fits will come with a little tweaking and polishing as you say. The finish on every part is beautiful though. It looks like the flywheel and eccentric are about all that's left. Looking forward to seeing it finished and running.

Bill
Title: Re: Pottymill horizontal engine build
Post by: Johnmcc69 on February 23, 2015, 02:19:23 AM
 :ThumbsUp:
She's looking real nice. Great job.

 John
Title: Re: Pottymill horizontal engine build
Post by: Stilldrillin on February 23, 2015, 09:02:18 AM
That is coming together, very nicely, Todd!  (http://freesmileyface.net/smiley/respect/respect-048.gif) (http://freesmileyface.net/free-respect-smileys.html)

David D
Title: Re: Pottymill horizontal engine build
Post by: steamer on February 23, 2015, 09:47:19 AM
Great build!    Cranks always seem to have a "Pucker" moment...no matter who's doing it!

Dave
Title: Re: Pottymill horizontal engine build
Post by: Roger B on February 23, 2015, 07:13:42 PM
Nicely done  :praise2:  :praise2: Still following along  :wine1:
Title: Re: Pottymill horizontal engine build
Post by: Thor on February 26, 2015, 11:36:42 AM
Hi Todd,
 
Your mill engine is coming along very nicely, keep up the good work and post more photos as you progress with the build.

Thor
Title: Re: Pottymill horizontal engine build
Post by: cfellows on February 26, 2015, 04:11:45 PM
Very nice work indeed!  Thanks for the many, high quality pictures.

Chuck
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 15, 2015, 02:34:05 AM
Well, it's been ages since I've checked in.  The main reason is that life and work caught up with me (so much for hiding in the shop!), and I also was heading into making a flywheel for this engine and took a little hiatus into thinking about the geometry of it all.   But meanwhile, I've been religiously following many builds including Don's grasshopper, Stan's down on the farm boy mini-series, and many many more.  I particularly followed Jo's battle with the 1802 bell crank engine which was quite inspiring to see her win against all odds.  I'll think more than twice about punting a project in the future.  And then there's crueby's kozo new shay build which I am certain is caught in some kind of time warp as nobody can work that fast in the universe I live in.

But you guys are certainly following those builds as well.  Back to this one.

The Flywheel

I'm starting the flywheel which is about 4 inches in diameter and is something I'd like to make fairly heavy to give this engine a chance of running slow even though it will suffer with my building tolerances.  A got a couple slices of 4 inch diameter cold rolled steel a few months back just for this purpose.  Hopefully I'll be using only one blank to get the job done!

I fired up Marv's flywheel app under DosBox on my android tablet and I got caught up in the calculations.  I got a snazzy new RT a couple months ago and it's barely been for a test drive.  This is my opportunity.  I'd like the work on the RT to be absolutely accurate, but I also know that if I screw up a little on the spokes, I should be ok anyway.  Thinking about how these angles might be calculated got me thinking about what the RT really does for a machinist.  It certainly implements the ability to work in polar coordinates vs. xy, but it also lets me rotate coordinate systems.  With that in mind, and with my (very) rusty programming skills, I whipped up a javascript-based web page that drew the flywheel with calculations.  Once I got the same numbers as Marv's I decided I'd better stop and just make the damn flywheel!  I'll get back to the software later.

So where to start?  It feels like I'm starting a new engine because I've been out of it so long.  I decided that since the flywheel was going to be so bulky, I'd better make a mandrel to hold it for finish turning.  I did that now as shown in the next few photos.  The shaft for the flywheel is 5/16 inch, and I plan to make the hub 5/8 inch, so I started with a 5/8 inch rod that was fairly beefy, turned it down, and threaded it.  I cut it off a little extra long in case I wanted to make a small mandrel on the other end for different diameter shaft.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150314_193644_zpsyh0zn7fu.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150314_201307_zpszxguvenv.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150314_202913_zps8f06trxx.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150314_203333_zpsfz2rbnwj.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150314_204514_zpsv5we7ox3.jpg)

So far that was pretty basic stuff, but I feel like I'm back into it again.  You guys have any advice for the mandrel?  I turned a short length near the shoulder so I can indicate off it when chucking the mandrel in my 4-jaw.  I did that while turning the rest so they would be true with each other.  Otherwise, I didn't put too much thought into it :).

I'm planning to do the trepanning over on the RT to remove the bulk of the material for the spokes, so the flywheel shouldn't be turning with its full weight, but it still concerns me some.  I might just use it for tidying up the outer surface of the rim...but we'll see.

Finally, I chucked and indicated the flywheel blank.  The blank is pretty rough, and there wasn't really room for my DI, but I did pretty good.  It's hard to tell with the roughness, but I'm certainly within 10 thousands all around.  Maybe better.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150314_205828_zpsfzwofwop.jpg)

And that's all for now.  It's too late to start turning it, so I decided to get a post out instead.  See ya soon.

Todd
Title: Re: Pottymill horizontal engine build
Post by: crueby on March 15, 2015, 03:06:56 AM
Glad to see your build going again!

Well, it's been ages since I've checked in.  The main reason is that life and work caught up with me (so much for hiding in the shop!), and I also was heading into making a flywheel for this engine and took a little hiatus into thinking about the geometry of it all.  But meanwhile, I've been religiously following many builds including Don's grasshopper, Stan's down on the farm boy mini-series, and many many more.  I particularly followed Jo's battle with the 1802 bell crank engine which was quite inspiring to see her win against all odds.  I'll think more than twice about punting a project in the future.  And then there's crueby's kozo new shay build which I am certain is caught in some kind of time warp as nobody can work that fast in the universe I live in.

And we are definitely following your build too! Time warps are for cheaters - I prefer just stopping time when I go into the shop....  ^-^
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on March 15, 2015, 01:19:13 PM
Glad to see you back on the project also Todd. Nice start on the flywheel!

Bill
Title: Re: Pottymill horizontal engine build
Post by: Jo on March 17, 2015, 10:36:48 AM
Hi Todd,

I particularly followed Jo's battle with the 1802 bell crank engine which was quite inspiring to see her win against all odds. 

I haven't won yet  :ShakeHead: the paint is too thick, the bearings won't go back where they should go. Did I mention the paint not sticking  :( After two weeks the crank is still not together but Kitti and Kiwi are so cute  :-\

Sounds like you have that bit of CI nice and true. I normally only line rough castings with the edge of the lathe tool or in the case of a bit of CI round bar not even do that and just "bung it in a three jaw"  :mischief:

Jo
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 19, 2015, 01:55:12 AM
I made a tiny amount of progress on the flywheel today.

In the last installment I had just chucked and centered a nice beefy hunk of cold rolled 1018 steel when I ran out of time.  It's about 4 inches diameter and a bit over 1 inch thick.  Now I went about cleaning it up a bit before taking it over to the rotary table.

I faced it off and was rather impressed that it was as flat as it was from a bandsaw.  I took a couple light passes to get to this point.  I think it was only about 30 thousands to finished.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150315_160024_zpsrizdvo9g.jpg)

Next I worked on the outer surface.  This crust was incredibly tough and was made further difficult by the fact that I didn't have much room on the cross slide to get over there.  You can see I'm using a carbide cutter which I've learned to dislike.  I just can't get them to cut like the HSS tools I grind (even though my grinding skills are *very* lacking).   I honed it a bit, which helped, but it still was very poor.  Of course it was fighting the crust...but didn't do well after it finally got through either.  I played with height a little, but couldn't find an improvement.  But I got through it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150315_164401_zpststbj2xl.jpg)

This was the best it would cut.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150315_200254_zpseefebuc0.jpg)

Here's the first side done.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150315_200958_zpsiefuqxcw.jpg)

Then off to the other side.  Indicating first.  You can see I'm challenged to setup a DI here.  I probably should have got the magnetic holder out, but I found this worked good enough.  I'm planning to do the final work on a mandrel so perfection is nice but, I don't think, required here.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150315_203003_zpslxgdg7ub.jpg)

It came out good.  Better aligned than I expected.  Ok, maybe my expectations were low...but that's what happened the last time I did this.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150315_222640_zpshzruyaad.jpg)

Finally I faced it off.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150315_223026_zpsb8pm3rrd.jpg)

Next was a matter of drilling and reaming for the shaft.  I went through 3 drill sizes (not all shown here), ending with N, and then reamed to 0.311.  I measured the drive shaft at 0.308 so this was the best I could do.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150318_184337_zpskgupll2l.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150318_190458_zpsqun3i6ci.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150318_190756_zpssbchwtly.jpg)

I got a real nice fit.  Now maybe this isn't the best thing to do with the engine, but at least I can say the lathe was unplugged :).  I slid it on about half way, not wanting to get it stuck.  That's a mighty massive flywheel at the moment.  I think it'll need a little thinning to be in proportion with the engine.  We'll see after I do some work on the RT.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150318_190929_zpsicq82rok.jpg)

And now to the RT!  This is getting exciting.  As I've mentioned before, I've never really used the RT before, other than a little playing around.  I'm not quite ready to trash this flywheel just yet (!), so I'll be experimenting for a while without cutters.  I need to align the RT, and align and clamp the flywheel first.  I've read and seen a couple videos on this, but any advice would be welcome.  I don't currently have any alignment gizmos, but the RT has a MT2 and I happen to have a MT2 center if that's useful here.  And of course my flywheel has a nice centered 5/16 hole I can easily use as a reference for some drill rod (I think I have some -- need to check for that diameter).

Any pointers to web sites or youtube videos would be welcome also.  Once I get it clamped and centered, I plan to hit it with layout dye and scratch out the lines using the RT and mill dials to verify I know what I'm doing, and that my measurements are right.   I have my handy sheet from my flywheel app printed ready to go, so you can see what I'm aiming for for the flywheel design.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150318_191852_zpsymn4czsl.jpg)

Well, that's it for now.  I'll be in learning mode for the next few days, but I'll keep you posted.  Hopefully it won't be too amusing :).

Todd
Title: Re: Pottymill horizontal engine build
Post by: rodw on March 19, 2015, 03:27:32 AM
Todd, Looking great. I am about as experienced with a RT as you are. I have an MT2 taper a mate machined on a CNC lathe that has a straight shank I can grab in the spindle. I have used that to centre the table, a sweep with my Coax indicator always shows that it is fairly close but not perfect. On the table like your setup, when using the Coax indicator, I found I had to rotate the spindle by hand because the T-Slots were in the way. I think you could attach a magnetic based indicator holder to the spindle for final adjustments.

I've been working on a stepper based rotary controller driven by an Arduino that has become a bit of a monster due to the feature set. I'm not sure if you want to get distracted right now, but it is all here http://www.homemodelenginemachinist.com/showthread.php?t=24118 (http://www.homemodelenginemachinist.com/showthread.php?t=24118)

It accepts input of the angles to the nearest second and you just push left and right arrows to move a division either way.

One day, I'm going to make this engine with your fantastic build log to guide me!
Title: Re: Pottymill horizontal engine build
Post by: Hans on March 19, 2015, 02:07:07 PM
Nice work, Todd! That was quite a large turning for that 7X lathe. Am I correct to assume that you are using a 5" chuck?

Hans
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 20, 2015, 02:19:13 AM
RodW,

That's a cool project you've got going!  I've really been wanting to dive into some gizmos for my lathe/mill, and I want to use it as an excuse to program an arduino, but I've been a good boy and have resisted the temptation for now so I can get a few engines behind me first.  But it's cool you are moving that one along over there (though my eyes boggle with the myriad ads on the hmem site...pffft).

DROs are very high on my list.   All along, and this is probably very naive since I haven't programmed an arduino yet, I've been thinking of marrying an arduino with an Android tablet.  Android tablets and phones are insanely cheap for the hardware they provide, and the arduino can do all the controller/realtime stuff.  I wanted to do this for DROs and happily ran into yuristoys a year or so ago and see he's already doing it.  So I'll probably go that route.  But we'll see.

Meanwhile, I'm trying to do a little giveback here by posting beginner stuff (which I CAN do :)) and will soon slide into a little software, I am fairly certain.  I should also look to see if there is a way to donate a little cash to the cause of running this site.  There's a lot of volunteer work here, sure, but there is also physical hardware, network and electricity to pay.

Hans,

Yes that's a 5" chuck.  In particular, it's the #2346 chuck and adapter from littlemachineshop.   When I bought it I was thinking I needed a 4-jaw and needing more capacity.  It is VERY big for a 7X lathe, and I think a bit overkill.   I did another engine last year with, if memory serves, a 3 or maybe 3.5 inch flywheel that didn't fit the standard 3" 3-jaw, but was small for the 5" so I had to move it in a step in the jaws.  That was tough on the nerves with those jaws flinging around at me.

I should have mentioned that chewing through the crust of this flywheel really did put a heavy strain on the lathe.  Those plastic gears in the head (the hi/lo gears) clicked a few times and I thought for sure I was going to trash it.

BTW, is there a real use for the high speed setting on the 7X lathe?  Honestly, I've never thought to shift it there before.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 20, 2015, 02:47:59 AM
My apologies for the excruciatingly slow progress.  Hopefully excitement will build over the weekend, but for now I centered up the RT.

I found a use for my MT2 center...it helped me get the RT roughly on center like this.  I had a 3/8 inch collet in the mill because my DTI will fit into it.  Hopefully this isn't trashing anything.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150319_212422_zpsaznrine1.jpg)

While it was held down by the mill, I shifted the XY slightly so I could bolt it down in place.   I inserted a DTI (a cheap one, unfortunately) and found I got it to within ~10 thousandths all around.   So a couple adjustments on X and Y and it's way better than half a thousandth, or whatever my DTI can really tell me, anyway.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150319_213609_zps7rrhspsp.jpg)

Not exactly a riveting story, but it surprised me how close it got so I thought it might be worth showing.  I didn't really have time to work in the shop tonight, but sometimes you've just gotta sneak in there to do something even if it's small, right? :)

Todd
Title: Re: Pottymill horizontal engine build
Post by: rodw on March 20, 2015, 03:17:58 AM
Todd thanks for the encouragement on the software front. Its taken me a couple of years to get to here and then just when I thought I had it finished, I smoked an expensive stepper driver as I was setting up for what I thought was the last test session..  :zap:

There is a setting in HMEM's profile to turn the ads off so I don't see them anymore.

Glad you got your RT centred and finished it off with an indicator. I've got the same table. This morning, my local machine shop had a sale so I went along and I saw they had a chuck backing plate for it with an MT2 taper pressed into the centre so I'm adding that to my to do list. It is hard to centre the chuck after you centre the table and the last time I did it, it moved half way through the job. Fortunately, it wasn't critical on the job I was doing, just annoying. I'll tighten things up next time!
Title: Re: Pottymill horizontal engine build
Post by: kvom on March 20, 2015, 11:22:08 AM
That brazed carbide turning tool is inferior in my view to one that uses inserts.  I think you'll like turning with carbide a lot more if you switch.

Engine coming along nicely.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 21, 2015, 07:37:10 PM
Marking out the flywheel (part 1)

Since I'm new to using a rotary table (RT) I thought it wise to go through all the motions once and see if it will produce the cuts I want.  This is somewhat artificial because scribing lines on layout dye won't be accounting for cutting diameters, but I'm confident the practice will be worth it.

I was originally planning to do the trepanning to create the webs on the mill, but this flywheel is big enough I've decided to do that the "traditional" way over on the lathe.  But for now, I'm going to this test drive on the flat surface of the side of the flywheel as it'll be easy to mark without hubs and rims getting in the way.  But this does mean I'll need to repeat parts of this again when I'm doing the real cuts.

Here's what it will look like.  The dimensions are in inches.  I've been tinkering with the proportions as I go along.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/Flywheel_zpsqtylp3y9.png)

Before I can mark it out, I had better learn how to center and clamp it down.  I realized the T-slots on my RT were smaller than on my mill.  So in the process of looking up their size, I remembered other accessories came with the RT -- including a clamping kit.  So I was in business.

First I centered the flywheel using 5/16" CRS rod.  I didn't have drill rod, but there was zero play so I'm pretty confident it'll be ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150320_102953_zps3pzwoxvt.jpg)

For marking it, I need the clamps tight so it doesn't wiggle around, but I'm not actually milling so I tried to push the clamps as close to the edge as I can.  They worked pretty good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150320_105554_zpsbypzhxlu.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_095107_zpsdlz9nhbp.jpg)

Ok...onto marking it out.  But first I had to think about how I was going to scratch into layout dye.  In particular, how was I going to scratch out circles to represent holes I will drill later?   Here's what I came up with.

My outer holes in the web will be 0.188 (3/16) so I found a bit of scrap 3/16 rod that was already drilled.  I turned it from the inside until it was sharp around the rim.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_100231_zpsjbhxf8zb.jpg)

Over on the mill I gave it a little test.   Note that the MILL IS UNPLUGGED for this entire process.  All I did was lower the mill to contact this little scrap with layout die, and then I gave it a twist of maybe 1/8th turn.  It measured plenty good.  That wasn't something I was going to draw by hand.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_100422_zpso307ih2z.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_100612_zpslmjvhaaz.jpg)

The inner holes in the web will be 0.375 (3/8 inch).  So I repeated the process.  This time I ended up drilling.  It didn't produce a crisp edge, so I tried a countersink and it cleaned it up nice.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_102300_zps7jx3rn1t.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_102508_zpsuot9q7qd.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_102647_zpsm7wtfgoq.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_102802_zpsiddvfhup.jpg)

The last thing to produce was something for scratching the straight lines.  Instead of chucking a scribe, I just made a point at the end of a 3/16 rod.  In hindsight, hardening it may not have been a bad idea.  When it got dull, though, I'd touch it up on the lathe.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_105157_zpscx5vjcze.jpg)

I pulled the flywheel from the RT and painted it with layout dye.  While it was drying, I went through the process of re-centering the RT.  I wanted to make sure the last adjustments I made were in the "pushing" (clockwise) direction.  I wasn't certain if I had done this yesterday...and I had to wait for layout dye to dry anyway.  I also marked the X and Y with a grease pencil.  I learned that trick from That Lazy Machinist youtube videos.   He has loads of great advice over there!

Now I can return to zero from the clockwise direction at any time, and these blue marks will get me on the correct full turn of the dials every time.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_123527_zpsqvc5u63e.jpg)

This one on Y is a bit hard to see...but it's there on the base casting.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_123541_zpszrlmc1aa.jpg)

With everything clamped down and zeroed out it was time to make some marks.  I decided that the circle for the hub and rim were harmless enough.  I dialed out 1/2 of 0.625 in X for the hub radius.  This was somewhat entertaining and gave me a chance to look around where everything was, how far it moved in one crank, etc.  It was nice not having to deal with a cutter.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_124828_zpswdygzfmj.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_124951_zpsitd0wfyf.jpg)

The rim was a little more tricky because the clamps were in the way.  Fortunately I'm only marking, so I simply raised the mill head as I got to them and skipped over that little bit of layout dye.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_125616_zpsqikmle6y.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_125935_zpsgoxwqala.jpg)

Next, I'll lay out radial lines to represent the spokes.  These are the dotted lines in the drawing.  I have 5 spokes so these are 360/5 = 72 degrees apart.  I turned my RT to zero.  This is a grizzly H7527 rotary table, but I suspect most look like this.  I had to ensure the scale up on the table was at zero as well as the handwheel and vernier.   Easy enough.  I decided to draw the lines down the X axis (to the right) since that area on the mill table is easy for me to see.  Any of the 4 directions would work, of course.

Here is my RT's zero setting.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_130048_zps18lpxnkt.jpg)

I had already scratched out the first radial spoke so was able to immediately rotate to the next spoke at 72 degrees and scratch it out.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_131810_zpsrxa7wnfh.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_131912_zpsurcxm5gm.jpg)

That looked fine.   So repeat 3 more times!  One at 144, one at 216, and the last at 288.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_132003_zpsw06ppev7.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_132013_zpsgjnidfz9.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_132106_zpsrc2yfgtl.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_132200_zpstvmjr2u1.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_132237_zpszyaxifsn.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_132402_zpsjvoamki9.jpg)

Now the dial was returned to zero (another 72 degrees) and everything lined up as expected.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_132503_zpsi6dg6jnf.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_132524_zps5wibewut.jpg)

One super duper simple RT task behind me.   Next is the fancier stuff.  I'll layout the hole positions by drawing the holes with the tools I made, I'll sweep out the outer arcs, and then I'll position and draw the cuts between the holes which (hopefully) will simply follow the software's calculations.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 22, 2015, 02:11:57 AM
Marking out the flywheel (part 2)

In part one I made some scribing tools and got the radial markings for the spokes made.  I also scribed rings representing the hub and the rim.  Now I mark out the rest, which is the important stuff because this is what I'll be milling later on.   But for now this is practice and I found a few things I was doing wrong with my RT along the way.  Better now than with a cutter.   FOR THIS ENTIRE POST THE MILL IS UNPLUGGED.

Remember, I said the mill was unplugged.

Laying out the holes comes first.   When I'm doing this for real I'll simply drill these out.  But I wanted to make sure all the math works and the lines match up.  As a bonus I'll get to see it drawn up full scale by the mill.

I'm making a 5 spoke flywheel and using a single larger hole to make the bottom edge of the opening between each spoke.  Therefore the spokes are 72 degrees apart.  The inner hole is centered at 36 degrees (halfway).  So I rotated the table to 36 degrees and dialed out the X axis to the radius of 0.625 inches to find the first hole's center position.  My RT rotates 4 degrees per rev of the handwheel, so this took 9 handwheel turns.  Easy enough.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_153938_zpsgn6frorp.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_154119_zpsc3nsa4aw.jpg)

Layout of the 2nd, 3rd, 4th, and 5th hole couldn't be easier.  All I had to do was rotate the RT the spoke angle of 72 degrees which is 18 handwheel turns.  When I was finished scribing the last hole, I had to rotate a final 36 degrees (9 handwheel turns) to get back to zero degrees.

This one was at 108 degrees.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_154316_zpshlfrxtwo.jpg)

180 degrees
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_154421_zpshbyfkshe.jpg)

252 degrees
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_154532_zpswgddaexq.jpg)

324 degrees
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_154700_zpsv1kxaw3c.jpg)

All these handwheel turns is very similar to the XY handwheels.  It's easy to lose count.  Over the past few months I've learned to calculate up front how many full turns and partial turns to do BEFORE starting to move anything.  More important, I write it down in front of me...usually in the form A+B, where A is the number of full turns and B is the leftover.  That leftover is thousandths on the XY handwheels, and now on the RT it's going to be the last +3 degrees + min + sec.  I need to figure out what I need to do with that.  Maybe it's an A+B+C'D'' or similar.

I've also learned that when counting a large number of full turns (and 18 is getting large), that it helps not to look at the numbers on the dial.  I mentally think of a rough position where the turn is "done" but comes up short...so on the last turn I can take it from there to carefully position to the exact spot.  Then as I turn it fast I tend to watch my thumb that's on the handwheel and count it when it goes past that position.  It really helps.  Otherwise I get distracted trying to spot the zero as it flings by, and that leads me to pause as it goes around.  And that leads me to wonder if I just paused ahead or past the turn.  I'm curious what other tricks people have for this.  DROs eliminate the need, I suppose, but the RT may not have a DRO.  So welcome to the club if that's your situation :).

The outer holes were fairly easy too, except on the first one I realized that the spokes are going to be rather thin with the plan I had.  The 7 degree angle would have resulted in a spoke that thins to 0.162 inch (less than 3/16).  I added a little code to my software to compute that, and settled on 8 degrees which produces a spoke that is 0.212 inch thin at the outer edge.  On the plus side, 8 is a nice multiple for my RT.  Another lesson learned.

These next two photos show the 7 degree angle.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_155236_zpsinu2pyro.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_160046_zpsn30fxb9o.jpg)

Marking out the outer holes was fairly easy.  I could do them all in one pass, and with them all being multiples of 4 degrees (i.e. multiples of full handwheel turns) I could alternate 14 cranks and 4 cranks to lay them all out.  BUT, to save on the brain, I went around in two passes doing the "odd" holes first (so to speak) and then doing the "even" holes.  These are ALL 18 cranks apart.  Not much room for error.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_161958_zpsuwuttxc8.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_162108_zps8kb42gxc.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_162214_zpsuufg0uzv.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_162315_zpsefaiizkp.jpg)

The angles ended up being 8, 80, 152, 224, and 296, but mostly I was paying attention to counting cranks.

Next I had to shift to the "even" outside holes.  Rather than back up the RT, I moved forward instead.  Since I was over an "odd" hole right now, I knew I had to advance 14 full handwheel cranks to get to the right spot.   As an alternative, I could have moved back to zero, and then moved forward 72 - 8 = 64 degrees (16 cranks).

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_162449_zpsaduw28vw.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_162553_zpsxygvbxao.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_162656_zpsbkbgl3ku.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_162804_zpsm4x5eaza.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_163025_zpsr9c0ncd9.jpg)

The angles ended up being 352, 64, 136, 208, and 280.

Now is the fun part.  How do you connect the outer edges of the inner and outer holes?   This is what Marv's flywheel program computes for you.  My little prototype software does the same and tells me I need to rotate the table 4.61 degrees and shift it by 0.220 inches.  For grins I ran Marv's flywheel and it produced an angle of 4.563 degrees and a shift of 0.219.  The discrepancy might be rounding within the math (I used some numbers 4 decimal places out).

First, the shift.   I had to back up my Y axis 220 thousandths.   My handwheel is 62.5 thousandths per full turn, so this is 3 turns minus 32.5 (going backward).  So I backed up 4 full turns and then advanced forward to 30 on the dial.  This represents the -32.5 (remember the dial is 62.5).  You can see the setting in this photo, and note my little grease pencil mark from before.  I am not going to mess with the dial so I can easily find zero again.  I find that trick VERY handy!

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_164647_zpskicsvytf.jpg)

Now I had to dial in 4.61 degrees.  But since I pulled back the Y axis, I need this to be a negative 4.61 which is 360 - 4.61 = 355.39 degrees.  I'm treating the RT just like my other handwheels.  It has backlash so always go forward.  I could have backed it up extra far and then gone forward, but it goes round and round just fine (unlike X and Y!).

So what is 355.39?  I need to change it to degrees, minutes, seconds, so I'll make a mental note to fix my software to report that way.  But for now, that's 355 degrees.  That leaves 0.39 * 60 minutes = 23.4 minutes.  So 23 minutes and 0.4 * 60 seconds = 24 seconds.   355 degrees, 23 minutes, 24 seconds.   My RT only has a resolution of seconds to the nearest 20, so I'll be using 20 seconds.  So I set the angle, and realized later I didn't do this right!

I think you can see enough in the photo.  I have it set to 355 degrees, which is really 352 degrees via full turns of the handwheel, and 3 more degrees as a partial turn of the handwheel (note the 3 near the top right side of the photo).  Then I counted out 23 minutes...two major ticks for 20 minutes, and 3 minor ticks for the remaining 3.  But this was a mistake.  Later I realized there are 2 minutes per minor tick.  So I should have advanced it to one minor tick past 20, then shifted it forward so the +60 vernier tick lines up (the one at the bottom) and then advanced forward a bit more so the +20 vernier tick lines up.  It's easier than it sounds, but this exercise was great to force me to work that out.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_164253_zpsltdyyt0i.jpg)

BTW, my mistake set the angle at 355 degrees 26 minutes 20 seconds.  Converting this back, it's 355.44 degrees.  That's 0.05 degree off.  Over a length of 0.8 inches this will result in a Y error of 7 ten-thousandths.   I had to do the math to understand why my scribing didn't catch this. Whew.

Sorry...I imagine a lot of experienced RT users are sleeping right now :(.

In the next installment I'll scribe out these lines.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 22, 2015, 03:03:53 AM
Marking out the flywheel (part 3 -- the last part!)

Hopefully this detail will be helpful to someone.  I'll keep plugging along.  I really did learn a lot going through this.

In the last installment I had just shifted the Y axis and rotated the RT to get into position for an outer cut for the spokes.   For today, my MILL IS UNPLUGGED and I'm only scribing.  So my "cutters" are zero radius, I suppose.

Looking at the photo below, the position seems good.  The Y axis was pulled back toward me by 220 thousandths in the last installment, which is why I'm on the back side of the spoke line, and the RT is rotated (effectively) -4.61 degrees.  I know it's hard to see direction in the photo, but if I move along the X axis I will scribe from the outer edge of the hole to the outer edge of the other hole.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_164702_zpsfindv2v6.jpg)

I didn't want to scribe if my math (or thinking) was screwed up, so I shifted X to the other hole and found it was spot on.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_164809_zpsmzpuvfi7.jpg)

So I scribed it...
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_164849_zpsdwboeq1a.jpg)

The software, either Marv's or mine, doesn't report where to start and end in X.  I'll maybe add that to mine for reference.  When cutting for real the holes will be real holes, of course, and I think it would be wise to use an end mill with a slightly smaller diameter than the smaller hole.  Then the start/end positions for this cut won't be so critical.  But it may still be handy to have the numbers to get them close.

Now the cool thing is that I can advance to the next position simply by rotating the RT 72 degrees -- the spoke angle for this 5 spoke flywheel.  That's 18 full cranks on this RT.   The problem is that I didn't dare mess with the dial.  I really would have liked to zero it out, but I don't want to re-find the real zero later.  So this meant counting out full turns and finding that 3 + 23 minutes + 20 seconds finishing spot each time around.   It was fairly tedious, but there were only 4 more turns so it wasn't so bad.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_182033_zpsuewi3u7i.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_182221_zpsmzyp1y3y.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_182419_zpsl8cmzqcz.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_182636_zpsez3q82un.jpg)

Now I had to readjust for the other side of the web.  This meant dialing Y forward by 440 thousands (twice 220).  I used the grease pencil mark to reassure me I got this right.  It was forward so there was no backlash to deal with.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_183055_zpshmfuc40g.jpg)

I dialed the RT forward to 4.61 degrees which is 4 degrees 36 minutes 36 seconds.   This time I got the crank positioned right.  Or at least I think I did.  See the photo.  The 4 degrees is a full turn so I ended up past the 0 on the dial.  I advanced forward 3 big ticks (30 minutes) and 3 more smaller ticks (+6 minutes).  Then I had to advance forward until the +40 tick on the vernier lined up.  That's hard to see in the photo, but it's the 2nd tick past the 0 on the vernier (left) side.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_183709_zpszclu6nql.jpg)

Now that I can run the dial properly, the rest was easy.  Trace out 5 more edges.  I alternated the direction I scribed out of laziness.  With a real cutter I wouldn't do this.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_183814_zps0hx8rgib.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_184035_zpsiyqjgrjd.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_184151_zps0czon6cn.jpg)

Note in this photo that I somehow managed to scrape an arc in the lower right area of the photo.  I'm not sure how I did that, but perhaps I didn't pick up the scribe fully when I cranked to the next position.  I need to be more careful.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_184326_zpsggpoh7us.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_184436_zpsqcmd2lmk.jpg)

And now we are almost finished.  As I'm using real cutters I'll probably do this in two or three passes.  To do this, I think it's simply a matter of moving Y a little further out.  Instead of 220 thousands, I might use 225, and then take the last 5 thousandths as a second pass.  I'd do this by going around all 5 spokes at 225, and then going around again at 220.  Seems reasonable.

Note that rogue arc on the left side.  I decided not to "fix" it.  But don't confuse it with the outer arcs I am about to make.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_184613_zpsnvbfcnff.jpg)

I just have to produce the arcs on the outer edges of the webs.  The first step is to center again.  All I had to do was crank to my grease pencil mark and dial to zero and it was done (only showing X here).  Very cool.  Thank you That Lazy Machinist!   I imagine this is a common trick, but it was new to me.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_184733_zpsflb7h4ko.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_184739_zpskru05pem.jpg)

To make the arc I had to dial out to the outer edge of the outer holes.  That's easy math.  My outer holes are centered at 1.4375.  The hole diameter is 0.188 which has a radius of 0.94.  So add them together and X=1.5315 is what I want.  Start/end is easy too, as these are angles.  The total span between spokes is 72 degrees.  The hole starts at 8 degrees and ends at 72-8=64 degrees.  Another way to look at this is that I need to advance 2 cranks (8 degrees), draw the arc for 14 cranks (56 degrees), and crank two more cranks to align with the next spoke.  Very easy.

Here's the first arc.  My scribe was getting dull :(
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_185157_zps1gakjnpc.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_185501_zps8npqkurl.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_185751_zpspanzftxq.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150321_190029_zpsgvl11knj.jpg)

And that's it!  Like the inside cuts, I think I'd do the arcs in two or three passes.  That's just a matter of adjusting X three times and going once around for each setting.

I think I've got this down.  Now I need to do some trepanning to form the rims and hub.  I'll do that on the lathe, and I think I'll make the flywheel a bit more thin.  Right now it is over 1 inch wide.  I'm thinking it maybe should be 3/4 inch wide or so.  Anyone have opinions on that?

Thanks for following my arduous journey.  I learned a lot.

Todd
Title: Re: Pottymill horizontal engine build
Post by: ths on March 22, 2015, 09:07:02 AM
Hi Todd, that's a very instructive and detailed post, and a very useful one at that. Many thanks, Hugh.
Title: Re: Pottymill horizontal engine build
Post by: vcutajar on March 22, 2015, 11:24:11 AM
Todd, that was an excellent step by step instruction of how to do it.  I am sure that everybody, especially the beginners will appreciate the extra time you took to do it.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 24, 2015, 01:13:08 AM
Trepanning the Flywheel

This "trepanning" term is a funny one.  If you look it up the creepy medical definition comes up (ok, nearly everything medical is creepy to me :)), but it also refers to creating a hole by cutting a ring.  I suppose that's what a hole saw does.  It seems like we could use a better term for this since the goal of trepanning the flywheel isn't to create a hole, but rather to create a web for the spokes.

I sliced the flywheel down from 1.125 inch thick to ~0.75 using my bandsaw and then faced it down to 0.75.  This was entertaining and involved clamping a vise to my bandsaw to hold it.  I made partial cuts and rotated it a partial turn once in a while.  It was a long process, but it got done, and left me with a circle of steel that might be useful for something else.  If I didn't have a bandsaw, I would have made a HUGE pile of swarf instead.  Either way works.

My bandsawing was a little sloppy compared to the work from metal supermarkets...so I had to face off quite a bit.  Fortunately I cut far enough out so I had enough material left for the final 0.75 flywheel.  You can see one of my bandsaw cuts had wandered and it was very close to the final thickness.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150322_150338_zpsscqiojvo.jpg)

Now onto trepanning.  I had sliced off the top of the flywheel so the pretty picture I drew by scribing on the mill is no longer attached.  So I painted some layout fluid on the inner and outer parts of the face and scribed a fairly accurate line representing the final flywheel edge (rim and hub sides) as well as another line inland a little as a warning line.

I inserted my test shaft in order to measure the hub.  Simple math for that one.  You can clearly see in this photo that I'm producing a pretty lousy finish when turning the flywheel.  More complaints about that in a bit (apologies in advance :().
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150322_185228_zps7umxmcgz.jpg)

I used a cutter to scribe.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150322_185523_zpsnstrvoao.jpg)

Here's the set of markings.  Two inner rings (warning + final) and two outer.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150322_185645_zpsqb5ofdbb.jpg)

Now started trepanning.  I've only done this on one other flywheel and it didn't go so good.  That was partly because that flywheel was so tiny.  I didn't have excuses here, BUT the first thing I found was the range of my cross slide was horrible with my AXA quick change tool post.  I decided to try my original lantern style post.  Here I'm trying a cutter with a sharp clearance angle that was meant to clear a center.  I thought it might plunge better, but it was producing a bad finish and also wanted to chatter a lot.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150323_182014_zpslhfncjp8.jpg)

This cutter also chattered a bunch.  Blech.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150323_184124_zpsfpj3byqf.jpg)

I tried a couple more cutters I had previously ground.  I was getting a rough finish like this when taking off ~5 thousands.  It was frustrating and reminded me of the trouble I had when I was first trying to turn a rod on centers (way back here:  http://www.modelenginemaker.com/index.php?topic=3946.0 )
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150323_192000_zpshohnosa2.jpg)

I tried different angles, and I tried less overhang of the compound under the assumption that the setup isn't rigid enough.  I still got a lousy finish.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150323_192437_zpswmnwwhcu.jpg)

BTW, here's a better view of the setup.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150323_192500_zpsnbvztxpe.jpg)

Sigh...this will take some experimentation.  But I think I'm doing the right thing by taking the time to figure this out while I have plenty of material to remove.  I'm shooting for .188 deep and I'm still less than one third of the way there.  So I'll keep experimenting.  I'd grind a new cutter, but honestly I don't know what to grind.

I'll also re-check for cutter height.  I think I'm pretty close, but I can test that out more accurately.  I'll also experiment with lathe speed.  I've got quite a change going from the inside to outside on this, but so far I don't think that's it.  I'm producing fairly hot chips (i.e. they are noticeable when they land on me), but they aren't blue.  I also will try some fluid.  I'm cutting dry so far.

Todd
Title: Re: Pottymill horizontal engine build
Post by: sco on March 24, 2015, 05:52:05 AM
Treppanning is never easy - keep at it though and you'll get there!

Simon.
Title: Re: Pottymill horizontal engine build
Post by: rodw on March 24, 2015, 06:13:43 AM
Treppanning is never easy - keep at it though and you'll get there
Simon.

X2, Todd I feel your pain. I use insert tooling and tend to use left and right hand facing tooling and open it up with a neutral tool. But on small ones I had to do it on a 20mm OD part the other day and a 4mm slot on a 110mm dia face, I still don't have the right tool for the job. I will say upgrading my lathe made a big difference so I think rigidity plays its part but I guess you don't want to know that!
Title: Re: Pottymill horizontal engine build
Post by: Steamer5 on March 24, 2015, 08:23:08 AM
Hi Todd,
 Enjoying the journey with you, your laying out of the flywheel is first class!
When I turned up the wheels for the trolleys, 16 in total, I trepanned both sides of each using a round tipped carbide, 6 mm, I have an Emco 10 lathe so about the same size as yours by the looks, the wheels are about 110mm OD, about the only issue from memory is that the tool fouled when I approached final depth, the tool made a great job of the wheels.

Cheers Kerrin
Title: Re: Pottymill horizontal engine build
Post by: Jo on March 24, 2015, 10:03:56 AM
Hi Todd, I think your grief is being caused by the shape of your tool  :-\

I had a similar job to do recently on my Kitti's flywheel and I ended up using the same tool that I had ground for cutting the inside of the crank case:

(http://i214.photobucket.com/albums/cc12/jothoms/Kiwi%20Mk%20II/IMG_8782.jpg)

This tool is effectively a D bit, so it has the same angle at both the front and rear edges. Because it is made out of a bit of round HSS it does not foul on the bottom on the outer edge.

You could use a tipped boring bar to rough out the bulk, but I must say that I have been feeling more and more inclined toward HSS, it does do an excellent job.

Jo
Title: Re: Pottymill horizontal engine build
Post by: Hans on March 24, 2015, 01:38:08 PM
Todd, the layout exercise was very helpful. Thanks for uploading all of the detailed photos.

~Hans
Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 30, 2015, 03:37:23 PM
Trepanning the Flywheel (part 2)

With the day job getting in the way, progress on this engine has slowed.  I did get a bit of progress done this weekend, mostly consisting of experimenting with various cutters and angles to make trepanning go just a bit better.

I started by grinding a couple new HSS cutters.  I tried making a round one, even though my HSS blanks were rectangular, but it came out pretty good.  I thought this might work well for "dishing out" to get to depth, while I use a traditional straight cutter to square things up.  Note that I used a little layout dye for the HSS.  I had scratched a semi-circle around a bit of drill rod to provide a guide for grinding.  My grinding skills are improving a little.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150328_103106_zpsakbez5gz.jpg)

The round cutter worked ok, but you can see that I got heavy chatter toward the edges.  In theory this was going to work ok.  I'd just make the cut area smaller and smaller.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150328_104040_zps6mqvidyq.jpg)

I continued to "dish" it some, and then went with a straight cutter to square things up.  I still have a long way to go, but thought it best to keep experimenting while I had plenty of material to work with.  I went back to my big quick change tool post as the smaller lantern holder wasn't making it any easier.  Note also that I'm working on the back side of the flywheel with the lathe running in reverse.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150328_112827_zpsdjwjbl0d.jpg)

I experimented with various ways to present the cutter to fit in the space I had.  Remember this is a 7x12 mini-mill and a 4 inch flywheel.  This first photo shows a setup that was a little dicey.  I wasn't too concerned about losing the cutter as both screws were holding it down, but it needed a heavy angle for clearance and it was too difficult to see.  The following photo shows a more traditional approach, but running on the backside in reverse.   They worked better than before, but range of where I could work was limited by both.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150328_203422_zpsqzqchoft.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150328_203720_zpspwsqfr8z.jpg)

I went back to dishing it out with the round cutter until I was very close to full depth (0.188 which is 3/16").  In the first photo the bowl shape  can be seen along with chattered edges.  Chatter was my enemy in this task, and was also a problem for the straight cutters.  I quickly learned to use chatter as my guide that I was running into the edge and it was time to head back the other direction.  I'd advance using the compound while simultaneously advancing the cross slide.  Passes were, unfortunately, very shallow so this took many passes.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150329_155446_zpskqyohbzl.jpg)

To square it up again I went back to a straight cutter and worked on the back side in reverse.  I'd advance the cutter until it was barely making a cut and then work toward the rim.  As I did this the cutter would effectively be deeper and deeper as I went because it was dished.   Eventually it would chatter so I'd retract the cutter a half turn or so, then continue on.  This gave me a stepped edge as seen in the following photo.  Once I got to the edge, I went back and removed the steps one-half depth at a time for each.  That worked well.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150329_162106_zpsw4pxfmvb.jpg)

I did the same with the hub, working on the front side this time.  The cutter barely fit there.  But it was all squared up.  As I did this to the rim and hub I measured with calipers.  These dimensions weren't critical, but I wanted the rim to be about 0.313 (5/16") and the hub to be 0.625 (5/8").  I left the rim 10 thousands oversize because I'll be skimming it off later on the mandrel.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150329_180502_zpsyhpsfnkv.jpg)

A little sandpaper and scotchbrite fixed it up nice.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150329_185738_zps3iervgge.jpg)

So of course I get to do it all over again.  I flipped it around, marked the edges of hub and rim again, including warning lines, and got it running true with a DI again.  Note that I had to get a little creative with the compound slide.  This orientation worked so well, I used it for the following cutting steps.  It allowed me to work on the front side of the flywheel which was a little easier to see.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150329_191713_zps7gk6xdjq.jpg)

I started dishing again as shown in the following photo.  But now I realized I haven't tried my pointed brazed carbide tools.  I haven't been using these much and they seemed pretty sharp.  I touched it up with a diamond hone and tried it, and to my surprise it not only worked back and forth like the rounded cutter, but it left a fairly decent finish so long as I advanced reasonably slow.  This is shown in the second photo.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150329_193037_zpsompvcb5s.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150329_204621_zps53vxiyo1.jpg)

So I continued on until I ran out of time last night.  I got to 0.100 depth, so only 0.088 more to go.  You can see the edges are beveling as expected.  It's a little easier to see when the angled cutter is ready to make contact as I advance toward rim or hub.  It will chatter like crazy so as I'm getting deeper I'm not worrying so much about cutting as wide as possible.  When it's a hair from contact, I'll start cranking the cross slide the other way and advance the compound to deepen the depth.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150329_210720_zpsd31vqpt2.jpg)

Next time I should have the trepanning done.  All I need to do is get to depth, square up the edges, and sand/scotchbrite it a little.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on March 30, 2015, 04:23:57 PM
Todd, maybe I missed something. Won't you have to lay out all the holes again now for your spokes? In addition, did you consider using the RT and mill for this rather than trepanning on the lathe?

Bill
Title: Re: Pottymill horizontal engine build
Post by: MMan on March 30, 2015, 05:47:23 PM
Hi Todd,

You may have got beyond this with your flywheel now but; I had similar problems making the 100mm flywheel on my Bass Stirling - chatter and hassle with the compound. I ended up taking off the compound and making a new base for the QCTP that allowed me to get to larger diameter workpieces and pulled the cutting point back over the saddle, reducing chatter. Here are a couple of pics.

Mman
Title: Re: Pottymill horizontal engine build
Post by: NickG on March 30, 2015, 10:13:16 PM
I struggled at first until I took a step back and thought about what was happening. As Jo said, This is what your tool needs to look like for the 'trepanning' operation. You need the radius to be smaller than that of the cut out. A normal facing tool with the tool post at the correct angle will allow you to get up to the boss.

(http://img.photobucket.com/albums/v287/NickG24/Poppin/FlywheelTool.jpg) (http://smg.photobucket.com/user/NickG24/media/Poppin/FlywheelTool.jpg.html)

Title: Re: Pottymill horizontal engine build
Post by: tinglett on March 31, 2015, 03:48:36 AM
Thanks for the responses!

Bill...yep, I'll need to mark it again.  The work before was practice, and practice makes perfect :).  I could have cut the spokes and then done the trepanning, but I wasn't so sure about introducing an interrupted cut.  Maybe it would work ok, though, but for now I get to draw it again.  Should be easy this time.

Mman...cool.  I know there are mods to extend the range of the cross slide in a 7x12, but I have my sights set on a slightly larger lathe in my near future.  But if I stick with the 7x12, I need to do something.  I could probably make something offset the full toolpost, too, I suppose.

Nick...I've been getting in there and making sure my tools have clearance, which wasn't true at first.  This was easy to fix when I was grinding the HSS cutters.  I don't think the carbide cutter was rubbing, but it's possible I didn't look.  Still, it was doing a good job and only chattering when the cutter edge hit a deep flat area.   I am curious about your side drawing, though.  Do you think the top rake (is that a top rake?  I should look up the terminology) needs to angle back like that?

I've been trying to get my brain around the difference from turning a diameter vs. turning a face.  Normally I run the cutter perpendicular to the lathe axis when I face off a part, which is why I was trying those crazy orientations to hold the cutter on the side.  But as I was thinking about this I was wondering why it was so.  The rake you have on the top would match the rake I would expect to use when facing so it does make sense.  I will try this when I get back to it later this week.
Title: Re: Pottymill horizontal engine build
Post by: NickG on March 31, 2015, 10:02:21 AM
Hi there, as a rule of thumb i thought it was supposed to be around 20 degrees top take for HSS cutting steel, 40 ish for aluminium and about 2 for brass or cast iron. True, I suppose the chip is forming the other way facing outwards so maybe a the top of the tool needs to slope more to the left  when looking from the end here. This worked well for me on the last flywheels I did for poppin though as they had quite deep recesses.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 05, 2015, 03:22:24 AM
Cutting the Spokes (part 1)

I've slowed quite a bit, but got a good start on the spokes of the flywheel today.  I finished trepanning the second side finding that cutters shown by Nick really do work well.  I ground a rake on the top, but it was only about 10 degrees and it seemed to help.  I'd still get some chatter at the edges, but it wasn't too bad.  I made nice shoulders on the hub and rim as before.

Next I mounted it to the mandrel I made earlier and trued up the outer rim.  This was just a few thousandths to clean up and I hit it with some scotchbrite for good measure.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_140813_zpsyjkdyavj.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_145158_zpso0qwvhyq.jpg)

Here's how it looks on the engine.  It seems to be a good scale for it.  I had to chuck it in my mill vise for the photo.  I suppose I'd better start thinking about how I'm going to mount it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_145628_zpslghmknoi.jpg)

I centered the RT and then centered the flywheel like this.   Interesting enough, it was still a bit off.   I used a DTI to finish getting it absolutely centered.  However, I'm only making spokes so it would have been ok as-is, but it was good practice for me.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_161754_zpsm0lgicha.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_162522_zpsy5aldhgx.jpg)

Next I scratched out the inner and outer radii for the spoke holes as well as lines representing the centerlines of the spoke.  I thought these would keep me oriented and signal mistakes.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_173239_zpshjxthex2.jpg)

My angles were easy.  With 5 spokes, 360 degrees / 5 spokes = 72 degrees/spoke.  My RT moves 4 degrees per turn of the dial, so that's 18 turns from spoke to spoke.  The inner holes are centered between the spokes at 36 degrees, which is an easy full 9 turns.  The XY table was locked as I drilled these, and I would set one of the locks on the RT each time I turned to hold things steady.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_174103_zps1vsc4sbn.jpg)

Drilling turns out difficult because my mill is Z challenged.  The center drill shown above was no problem, but this was to be a 3/8 inch hole and the bits were far too long.   I happened to have a set of numbered screw machine drills, so I used the biggest I had, #1, followed by a 3/8 2-flute (drilling) end mill.  They worked great and gave me lots of room.  It's possible the end mill would have drilled fine all by itself, but I went through the sequence for each hole.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_174236_zpsumriwokr.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_174509_zpsiexypqyh.jpg)

Then repeat for 4 more holes.  18 more cranks on the RT to position each, and lock the table.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_175051_zps0snvmwr3.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_175604_zps4u3rdgot.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_180052_zpsurc6apvm.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_180459_zpsic1locur.jpg)

After the center holes were drilled, 9 more cranks got me back to zero on the RT.  Next I cranked two turns for an 8 degree offset for the outer holes.  I had to crank out X on the XY table to get at this radius.  I re-locked the XY.  These holes were 3/16 inch so my regular drills worked fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_191605_zpson6p1uat.jpg)

After each hole, crank 18 for the corresponding hole on the next spoke.  Note that this means I was skipping the other holes.  That second pass is coming up.  I did this when I did a trial run a few posts ago and I'm convinced it's a good idea.  When it's always 18 cranks, it's hard to mess up.  Here are all five holes drilled.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_193213_zpsljizajsr.jpg)

Now I had to advance 14 cranks to get to the "odd" holes.  I could have gone backward, but it's less work thinking about backlash by moving always forward.  The spoke line was nice here because I could see the new hole was landing in the right place.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_193435_zpscctp2dto.jpg)

Then it was a matter of advancing 18 cranks per spoke and drilling the next 4 outer holes.   Here it is all drilled.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_194610_zpsk3s2zwml.jpg)

After this was done, Twenty more cranks (2+18) would advance me back to zero.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150404_195323_zpsguyoa6p5.jpg)

Hmm...but now I see a new problem.  I need to cut out these webs with a mill, and my clamping is going to get in the way.  I'll start by replacing those bolts with short ones, but that might not be enough.  I may need some lower profile clamps of some kind.  Always something.

Thanks for checking in.

Todd
Title: Re: Pottymill horizontal engine build
Post by: NickG on April 05, 2015, 02:51:58 PM
Nice work, the engine is looking good. I need to try cutting a flywheel with spokes from the solid now I've got a rotary table. I think they often look better that some of the grotty castings I've tried.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 08, 2015, 03:45:10 AM
Cutting the Spokes (part 2)

In my last post I drilled all the holes that are the "corners" of the cutouts that form the spokes.  Tonight I decided to cut the arcs on the outer edge of these openings.  If this isn't clear, the photos will show what I'm up to.

I decided to cut these in at least two passes.  In the end I took four passes until I was satisfied.  With the RT and flywheel centered under the mill head, I cranked out the X table until I was at the outer radius.  My outer holes were 3/16 inch and it so happens this is my smallest end mill so there wasn't extra math to calculate the end mill's outer edge.  In order to do multiple passes, I cranked out X so it came up about 12 thousands short of the full radius.  Also, when I cut the arc I started 4 degrees into the opening (i.e. one extra crank) and I stopped short 4 degrees.  So instead of 14 total cranks for the arc, I used only 12 while roughing it open.   I took 3-4 passes to get to depth.  Anything deeper seemed to be too much for my mini-mill.

I started with a 4-flute end-mill because it was longer and I had clamps to clear, but by the second slot I decided to try the 2-flute and found it fit in the space (barely).  Here's the setup where I started with the 4-flute.  Maybe you can see I'm slightly inland and I know it's clear I'm a few degrees into the cutout.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_173644_zpswbd2nxgp.jpg)

I took a shallow cut as my first pass.  This is the first time I've rotated the RT while milling so I wasn't sure how stable it was going to be.  It was pretty smooth.  I took the opportunity to plunge on both ends during this pass.  I think this was a good idea for the later cuts because I could hear when I was at the end of the cut as I moved into the pre-cut opening.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_174443_zpsnmlos0in.jpg)

This photo from above makes it pretty clear how I shifted the cut inland.  The working theory was that I'd make these cuts all around, and then make a light finishing pass at the full radius and length of cut.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_193545_zpsj0qihh6n.jpg)

As I switched to my 2-flute for the second cut, I also remembered to set my Z depth stop.  This was a very good idea because I would no longer need to worry about trashing my RT.  I'd also use the visible distance of mill head to stop to eyeball my depth adjustment when making the 3 passes.  I also used locks when I could.  My XY locks were always on, and I would lock the RT whenever I was plunging.  And I'd use the Z lock whenever I was cutting while rotating the RT.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_193716_zps5wkswog9.jpg)

I went around making the five cuts for the five spoke cutouts.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_202228_zpsi9l9qtgr.jpg)

So far so good.  Looks a little rough.  Now time to clean up.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_203015_zps6bkhatid.jpg)

I went around at the finishing radius which was an easy 10 thousandths to remove.  But note the bit of gouging that still remained.  Maybe I should have reserved 20 thousandths.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_204927_zpszqfvdjer.jpg)

The outer radius for the spokes isn't that critical provided I don't change the start/end angles.  So I took another 5 thousandths.  It wasn't good enough, but another 5 thousandths got me into the ballpark.  It's looking pretty clean.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_210210_zps9bllqv81.jpg)

And that's about it for today.  It occurs to me that I haven't backed up the camera to show the whole setup in a while, so here it is in case there's something I forgot to say about it.  Sometimes a picture is worth a thousand words as they say.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150407_210239_zps2qagpcbe.jpg)

Thanks again for checking in.  This weekend I'm hoping to finish off the spokes.  The next cuts are the "tricky" ones that require I shift the XY and turn to an angle to cut between the inner and outer holes.  That ought to be interesting.

Todd
Title: Re: Pottymill horizontal engine build
Post by: NickG on April 09, 2015, 05:15:46 PM
Looking good Todd, there is quite a lot of working stuff out isn't there. Did you cut at full depth for the finishing passes on the outer rad and did you go both ways or avoid climb milling?
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 10, 2015, 03:38:06 AM
Nick,

Yeah, for the finishing cuts I did them at full depth in a normal (not climb) cut.  I guess I didn't think too much about direction.  I assume a climb cut might pull on the RT a bit.  But the regular cut was in the right direction for "going forward" with my RT.     I was only taking 5 thousandths so it was a pretty easy cut.  I just dropped the head down onto the Z stop I set earlier and went for it.  The cutting was rather fast even though I went around for two passes.

I'm hoping there won't be too much cleanup to do when the spokes are all cut.  We'll see.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 11, 2015, 02:03:15 AM
Cutting the Spokes (part 3)

I got a little shop time in this evening ahead of the weekend.  I wasn't able to accomplish everything to finish the spokes, so there will be one more installment, but I made good progress.

Recall I had the holes drilled and the outer arcs cut by the end of the last installment.  Now I will cut the radius that runs tangent from the inner hole to the outer hole.  Today I got one of these for each spoke cut.  All 5 spokes cut at the same general settings so it's less fidgeting to do them in steps going round and round the rotary table than it is to finish each spoke with lots of cranking of dials.

For my spoke configuration the software says I need an offset of 0.220 inches and a rotation of 4.61 degrees.  My RT uses degrees/minutes/seconds so this is 4 degrees, 36 minutes, 36 seconds.  I'll round that to 40 seconds which is what my table rotary can do.   Unfortunately these blasted settings are both backwards on the dials.  That means figuring out where the dials should land, rotating them further than that setting, and rotating back to hit the setting exactly going in the right direction.  I always go clockwise for this so I don't forget.

Now the offset of 0.220 does not compensate for the radius of the cutter I am going to use.  But I first dialed in 0.220 anyway so I can use my little scratch tool to verify I got the settings right.  Here it is...and looks pretty good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_170016_zpswhlyrfsp.jpg)

I dialed the Y to adjust 3/32 inch for the 3/16 diameter end mill I'm using.  I went an extra 20 thousandths so I can make cleanup passes after doing the slot cuts.  Still looking good!  The finished cut looks like it might be approximately 20 thousandths offset.  Good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_170651_zpsoqu5khes.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_171141_zpsfevm5mwv.jpg)

Now I need to rotate the RT 18 turns (72 degrees) to get to the next spoke position.  That's going to be error prone because I won't be stopping at 0 degrees on the dial anymore.  So if there's any real good ideas in this build log, it might be this one.  I figured I'll for certain screw this up, so I added blue tape like this to the top of the dial.  I drew a line off the end of a square, and then I slit the tape with a razor blade so I could spin the dial again.  It's painter's tape so easy to remove when I'm done.  I put it on top of the dial so it's easier to see.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_194812_zpshearmg3b.jpg)

Ok, well now it's repeat, repeat, repeat, until all 5 spokes are done.  All I needed to do was dial 18 cranks and use the blue tape as my target position for the 18th crank.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_172356_zpsieqwb5xp.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_173010_zpspywuxi6z.jpg)

I should mention that I wasn't really watching the X dial that much as I cranked.  It was easy to visually see the start and end of the path I was cutting so I wasn't too concerned about this.  The main thing was that I didn't want to do was gouge into the outer arc, so I'd start by plunging at the outer edge with the mill off in order to get the starting position right, and then I'd mill toward the middle.  I used 3-4 passes as before to cut all the way through.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_173115_zpsmwunk6yh.jpg)

Two more to go and the hard part's done.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_173635_zpsaka0jbjt.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_174419_zpse0rpdvhp.jpg)

Now was time to finish the edge.  I have 20 thousandths to go and decided to finish in two passes.   All I had to do was crank the table around, 18 cranks per spoke, and run off 10 thousandths.  I'd machine from the outer hole to the inner and back so I'd get a normal cut then a finishing climb cut.  The climb cut wasn't so important, but this got the mill back to a starting point for the next spoke (after I'd rotate to it, of course).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_174608_zps3hjvmwmi.jpg)

Here I got concerned.  That line didn't quite look like it was going to line up.  Sure enough, I realized I got the RT dial wrong.  Pppffft.   These markings on the RT's dial are going to take practice.   I think next time if I need to back up the dial I will back up a whole extra turn (i.e. -4 degrees) and then move forward to take the excess off.   That is, I'll calculate this forward setting and dial it in.  I'm finding it very hard to run the vernier on this RT...but learning to do it backward as well as forward seems crazy at the moment.   One thing I can do is eyeball the setting between the minutes and decide if it makes sense.  Getting the right minutes is probably "good enough" for this angle (better than 2 hundredths a degree).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_175421_zpsszdafjju.jpg)

Now they were looking better.  It's too bad there's a shadow here, but the spoke at 8 o'clock is looking pretty good.  Same with the one at 10 o'clock.  The other's only show the ratty cut on the inside that's going to be tossed.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_181737_zpscs1j9pem.jpg)

Finally, since I was going to call it enough for the night, I reset the Y offset, double checked it was still centered with a rod in the hole, and installed my marking rod to double check that I returned the RT properly back to zero.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150410_182636_zpsxtqdeamt.jpg)

Tomorrow I'll do this all again on the other side of the spoke.  I'm a little concerned about this one because the waste material is going to fall.  I don't want the end mill to bind up when that happens.  Not sure what I can really do about that, but I'm thinking it may help if I finish the cut at the large (inner) hole end so there is more space when it plops.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 11, 2015, 02:08:53 AM
By the way, hopefully *most* people see the photos in my previous post properly.  I find when I rotate photos in photobucket, it takes a long time for external uses of the photos to come up proper.  Very annoying.  I suppose I should learn to rotate the photos properly before uploading to photobucket, but you'd think they could get that right.

Next build log I'll try something different.  Meanwhile, I'll suffer with photobucket and hopefully you guys won't need to rotate your heads too much to see what I'm talking about.

Todd
Title: Re: Pottymill horizontal engine build
Post by: rodw on April 11, 2015, 02:51:51 AM
By the way, hopefully *most* people see the photos in my previous post properly.  I find when I rotate photos in photobucket, it takes a long time for external uses of the photos to come up proper.  Very annoying.  I suppose I should learn to rotate the photos properly before uploading to photobucket, but you'd think they could get that right.

Next build log I'll try something different.  Meanwhile, I'll suffer with photobucket and hopefully you guys won't need to rotate your heads too much to see what I'm talking about.

Todd

Windows photo viewer lets you rotate photos before you upload. The other free photo tool I've used for years is Irfanview. It has  a batch mode so I use it to downsample all my photos in a LoRes folder under the folder I store the photos in. Then I upload those photos to Photobucket.

These days I use Adobe Lightroom which is awesome and there is a Photobucket plugin available for about $3.00 so it can upload straight to Photobucket. (but I still create my copies in a LoRes folder like I did for years with Irfanview.)
Title: Re: Pottymill horizontal engine build
Post by: Jo on April 11, 2015, 08:32:39 AM
Tomorrow I'll do this all again on the other side of the spoke.  I'm a little concerned about this one because the waste material is going to fall.  I don't want the end mill to bind up when that happens.  Not sure what I can really do about that, but I'm thinking it may help if I finish the cut at the large (inner) hole end so there is more space when it plops.

Hi Todd, What I expect you will find is that as the last little bit is being milled the cutter pressure will push the waste material away from the cutting edge, add to that the fact that the waste will bend down due to its weight and it should all be ok  ;)

I bet you will be please to get over the wind, wind, wind of the mill handles. Any blisters?  :naughty:

Jo
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 12, 2015, 07:30:44 PM
Cutting the Spokes (part 3) and Finishing the Flywheel

It's the weekend and shop time.  Well, I got time on Sunday anyway and was able to finish off the flywheel.  It isn't completely done as it needs a little cleanup and polish as well as a way to secure it to the shaft (setscrew?).  But it's looking like a flywheel now! :)

Last time I had the arc and one side of each cutout finished.  Today was time for the other side.

Recall the software said the angle should be 4.61 degrees and offset 220 thousandths in the Y axis.  I'm going to the other end of the spoke, so this will be 72 degrees (the spoke angle) + 4.61 = 76.61 degrees which is 72 deg, 36 min, 36 sec.  I cranked it to that angle and updated my blue tape to the new position so I can find this angle again and again as I finish each spoke.  I offset Y by exactly 220 thou so I could use my little scratch tool as a sanity check.  Here it is after scratching from the outer hole to the inner hole.  Looks like the correct position.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_114659_zpswn2lvh7z.jpg)

I dialed Y an extra 20 thousandths so I could make finishing passes after cutting out the spokes.  I cut each using 4 passes, finishing in the larger inside hole.   As Jo pointed out, the pie wedge would angle away from the cutter until the left outer part would touch the spoke, but by then it would fall down harmlessly.  Nice.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_115543_zpszvxdpdwo.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_115643_zpswa287nvc.jpg)

Now I would do 18 cranks (72 degrees for my 5-spoke flywheel) to get to the next spoke and repeat.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_1202262_zpsukzcwsf5.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_122558_zpspr02an8c.jpg)

I did the first finishing cut by removing 15 thousands (of the 20).  I'd start at the inside hole where there was more clearance, work to the outside until you could hear it enter the outside hole, and then would return back to the inside hole to be ready for the next spoke.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_122834_zps4bplz7tb.jpg)

Here I had dialed to the exact measurement for the final cut.  It was clearly a bit off.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_123556_zpsjeocrakc.jpg)

With a little experimenting, I ended up taking off an extra 7 thousandths.  You can still see a little shade change where the hole meets the spoke, but it's very hard to feel.  I suspect the holes are slightly oversize.  But these are just spokes, so at this point I was only making adjustments to make the sanding and polishing work easier.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_1245532_zpstnfofimu.jpg)

This is about all I can do on the mill with RT.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_124605_zps9jrys1sv.jpg)

It matches the diagram.  Well, of course it does :).  Here you can see all the numbers I was working from as a reference.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_1251352_zpsroi0wylp.jpg)

And here it is on the engine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150412_125532_zpsld8sizne.jpg)

I'll need to trim the shaft to length and do something to secure the flywheel to it.  I'm thinking a setscrew would be nice, but not exactly sure how to drill in such a tight spot.  I could thread and/or loctite.  While I'm thinking about that, I may turn the engine around and work on the eccentric and valve linkage for a while.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on April 12, 2015, 07:50:51 PM
Nicely done Todd, I always enjoy seeing updates on this engine.

Bill
Title: Re: Pottymill horizontal engine build
Post by: John Rudd on April 12, 2015, 09:02:39 PM
Nice bit of machining there....as for securing it to the shaft, you could use a taper style fastening or just drill/tap a grub screw fixing by drilling at an angle.....
Title: Re: Pottymill horizontal engine build
Post by: rodw on April 12, 2015, 09:05:49 PM
It's really interesting to follow your progress. I'm sure others will have other ideas but I wonder if you could drill and tap for a setscrew on an angle? Hold the flywheel on a mandrel held in a collet block. If the sesetscrew was on the inside, it would hardly be noticed. Looks like John beat me to it while typing!
Title: Re: Pottymill horizontal engine build
Post by: Don1966 on April 12, 2015, 10:08:13 PM
A real nice job and save on your flywheel Todd.  :ThumbsUp:

Don
Title: Re: Pottymill horizontal engine build
Post by: NickG on April 13, 2015, 03:55:14 PM
Much prefer your flywheel to my casting from RDG. Lot of
Work in it mind you. Have you thought about running around the spoke edges with a 45 dog angles cutter? I haven't got one but have seen used to good effect - tried with a csk bit to put chamfered edges on but that didn't really work!
Title: Re: Pottymill horizontal engine build
Post by: Roger B on April 13, 2015, 07:55:08 PM
That's a good result after a lot of handle turning  :ThumbsUp:  :ThumbsUp:
Title: Re: Pottymill horizontal engine build
Post by: arnoldb on April 13, 2015, 08:46:52 PM
Very well done Todd - machining out a flywheel like this for the first time is quite a challenge, but you did everything right by going about it slowly and methodically  :ThumbsUp:
You'll find it's much easier the next time around  ;)

As to mounting it - yes, the simplest way is a grub screw, and I was about to point you to this (http://www.modelenginemaker.com/index.php?topic=4087.msg79352#msg79352) post of mine showing drilling and tapping at an angle for a grub (set) screw...
However, going back through your posts, I don't think you'll be able to hold the flywheel in your vise as shown in my post, as it seems a bit too big for your vise.  So you might have to devise a way to clamp the flywheel directly to the mill table at an angle, and as I'm not sure what you have available in your shop, that might prove a mission on its own to figure out  :)
Anyway, if you decide to go the grub screw route, an angle of about 30 degrees from vertical works nicely to allow for clearance for tooling.  It also complements the tapered tip on most grub screws causing less scarring on the shaft when it's tightened.  Just use a small center-cutting milling bit to spot a flat face before spot drilling and drilling the hole to threading size to prevent the drill bit wandering.

Kind regards, Arnold
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on April 14, 2015, 06:32:47 AM
Great job with the flywheel Todd  :ThumbsUp:.

I just threaded the end of the crank shaft then just a couple of washers and a nut is all you need to bolt it to the shaft.

Like this

(http://i431.photobucket.com/albums/qq32/sbwhart/Lads%20and%20Dads%20engine/IMG_0153_zps11a36505.jpg) (http://s431.photobucket.com/user/sbwhart/media/Lads%20and%20Dads%20engine/IMG_0153_zps11a36505.jpg.html)


If you want to go the grub screw route, glue it to a suitable size shaft and hold onto the shaft in the vice at a suitable angle as Arnold suggested, drill and tap, then heat the shaft up a little to release the glue a sharp tap with a drift should than knock the shaft out, clean away any glue residue:- job done.

Hope this helps

Stew
Title: Re: Pottymill horizontal engine build
Post by: 90LX_Notch on April 14, 2015, 11:02:56 AM
Todd-

This is coming along nicely.  The blue tape idea is a great one.

-Bob
Title: Re: Pottymill horizontal engine build
Post by: NickG on April 15, 2015, 07:25:53 PM
Nice work, I used the method Stew described which was good, nice and easy and better grip than the grub screw but on yours I would probably do the grub screw now as it would put stress on the crank when threading.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 19, 2015, 03:18:03 PM
Much prefer your flywheel to my casting from RDG. Lot of
Work in it mind you. Have you thought about running around the spoke edges with a 45 dog angles cutter? I haven't got one but have seen used to good effect - tried with a csk bit to put chamfered edges on but that didn't really work!

I did have a thought about this.  I think I'd make the spokes thicker and then a chamfer all around, or roundover, or perhaps ball nose mill or even a straight mill could make a nice effect around the spoke opening.  But for now I decided the flywheel was complex enough for me :).   Maybe next time.

I think I can do the math for curved spokes, too.  That would be challenging (and fun!).  Don posted about this in January: http://www.modelenginemaker.com/index.php?topic=4601

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 19, 2015, 03:39:22 PM
Mounting the Flywheel

I decided to go with the grub screw.  I could thread the flywheel and shaft and I can still go with that as a plan B.

Here's my initial setup.  I bolted down an angle plate at the back of my X table and rested the flywheel against it.  The flywheel is held tight in the the recess of the table with a single hold down.  I thought this should be stable enough for drilling.  I couldn't shift it with my hands, anyway.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150417_173939_zpsnmd0gsnw.jpg)

Well, I hadn't thought about the forces of an end mill, though.  I used a 2-fluted end mill to form a flat for drilling and found the flywheel was tending to shift.  Before I had a disaster, I stopped to consider how to make a more rigid setup.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150417_174647_zpsmohhxwg4.jpg)

I didn't have room for a clamp along the top edge of the flywheel.  I found the mill was trying to force it to the left, so instead I bolted supports in place on the right/left sides to keep it from rolling.  This was enough.  For good measure I used a small quick-grip clamp to squeeze it together.  This probably wasn't needed, but the clamp was handy.  I didn't have a C-clamp big enough.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150417_175629_zpstgor2vzz.jpg)

Now on to milling the flat.  Easy enough.  I had plenty of room for the mill head at this angle.  In fact, I probably could have put a spacer behind the top edge of the flywheel to tip it a bit more vertical.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150417_175930_zpsu29eve4q.jpg)

I drilled and tapped for an 8-32 set screw.  It's hard to believe just a few months ago tapping was difficult for me, and here I am tapping a steel part that had a lot of time put into it.  As I type this, I realize I had no concern at all about this was I was doing the tapping.  Nice.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150417_183333_zpsfvgnfvmw.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150417_183819_zpsoh43jylc.jpg)

Hmm...time to head to the home center for a shorter set screw.  But looking good.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150417_183933_zpswxswhpxp.jpg)

And here we go with the proper sized screw.  I chopped up a couple pieces of pine as a stand.  Nothing is bolted down, yet it balances well.  I'll probably go with a simple black walnut stand to match the other engines I've made so far.  It'll look like this, though the bottom piece will probably be a little bigger and chamfered to match the others.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_094146_zpsmzdhwccr.jpg)

Thanks for checking in.  Not a complicated task today, but important.  I want to keep that flywheel from rolling out the door!   Next is the eccentric mechanism.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 22, 2015, 04:21:38 AM
The Eccentric

This looked like a particularly fun part to make, and this turned out to be true.   I didn't get a nice consecutive set of hours in the shop, but with a little time here and there over the past few days I managed to get it done.

Its design is a sandwich, much like an Oreo cookie where the "good stuff" is a ring that is able to wobble back and forth without spinning while the outer parts of the cookie are attached to the shaft.  I was thinking it would look particularly snazzy if the ring was made of brass, so this is where I started the journey.

This bit of brass is a little too large, but was close enough.  I had parted it from the flywheel during my pipsqueak engine of a few months back.  That seems so long ago now.  I faced it and drilled a 5/16 inch hole to fit the arbor that I used for turning the flywheel.  The inside of the ring will be bored out later.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_094836_zpstdwwhucg.jpg)

On the arbor I was able to turn it down to 30mm diameter.  The thicknesses and diameters aren't that important, but I stuck to the original dimensions anyway.  I didn't want to find I was wrong about this the hard way.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_104047_zpsdkow0xcw.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_114458_zpsbwilv7zs.jpg)

While still on the arbor, I cleaned up the sides and narrowed it to 6mm.  While doing this that darn brass managed to grab and gouge a little.  Grrr.  But still, it will be sandwiched so I decided not to worry about that too much.  I only needed to clean up the sides for part of the diameter because I'll be boring it out to 20mm inside.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_115844_zpspnbwpaqi.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_120653_zpsfv94fvmm.jpg)

After drilling to 9/16 inch (my largest bit) I switched to a boring bar and finished it to approximately 20mm.  I simply used a ruler for most of the measurements, but then switched to a caliper as I neared the end.  I still haven't purchased any tools to measure an inside bore like this.  But this is why I turned the ring first -- I will turn the next part to fit the ring.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_161626_zpskchmxus4.jpg)

And here's the ring.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_162629_zpszunjgt99.jpg)

Now for the outside parts.  The next part will be turned to 30mm diameter also and turned down to fit the ring I just made.  It's CRS (bright) steel that started as 1.25 inch diameter.  I ended up placing it in the inner part of the outer jaws (how else do you say that?).  I probably could have used inner jaws and spaced it out, but this setup was nice and solid -- though I had to worry about those outer jaws spinning around.  I faced it on both sides and got it to final thickness of 8mm.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_172442_zpsvst1jxhl.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_173307_zpsqri7fl6f.jpg)


Again, I drilled 5/16 inch to fit the arbor.  The arbor was a useful thing to make for this project!  I turned it down to 30mm diameter.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_175859_zps9xupbdfo.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_181009_zpsbreffrxz.jpg)

Next I turned down 6mm of the thickness.  The goal was to get a nice slip fit for the brass ring I made earlier.  I measured until I got close to 20mm, and then I started using the ring to test as I took off 5 thousandths at a time.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_183422_zpszs8wewns.jpg)

Here I was very close as the ring almost fits.  One more pass.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_192346_zpswzqpyu82.jpg)

I got a fit.  Now I needed to clean up the shoulder as it was pretty sloppy.  That's shown in the second photo.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_192447_zpsabissmmt.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_193532_zpsijjpxgbc.jpg)

Then I took it off the arbor, chucked it, and bored it to 16mm.  Again, I drilled to 9/16 inch and finished with the boring bar.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_194833_zpsspq9mylb.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150418_201509_zpsiwcehsmd.jpg)

And here is the pair.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_095247_zpsmzneogpm.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_095259_zpsmntvkchm.jpg)

I'll finish logging this one in another post.   The other half of the cookie fits inside this 16mm bore and has the offset for mounting on the shaft.

Thanks for looking in!

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on April 22, 2015, 01:14:13 PM
I still really like the looks of this engine and the design in general Todd. And on top of that your photos are excellent!!  Looking forward to seeing the completion steps and getting her running too.

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 23, 2015, 03:07:00 AM
Thanks for following along Bill...I am getting near the finish line.  Everything is a little stiff and I fear I may need to remake the piston rod and maybe even the valve rod.  We'll see.  But it's looking as nice as I could ever wish.  Maybe this weekend I'll make a real wood base for it, too.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 23, 2015, 04:06:04 AM
The Eccentric (part 2)

I was hoping to get this written earlier today, but better late than never :).

In the last post I was building the eccentric which is an Oreo cookie-like arrangement of three parts that fit together.  The good stuff in the middle is a ring that will be drilled and tapped for the eccentric push rod that operates the valve.  In that last post I made the ring out of brass, for the sex appeal of course, and made the simple side of bright steel.   Here I make the other side which includes the eccentric offset.

As with the other side, I started with a hunk of 1.25 inch CRS (bright) steel.  This one is a bit longer as the finished part will be 15mm thick.  I faced both sides roughly and then needed to chuck it with enough material exposed to turn down an 8mm section.  Perhaps I should have used a longer length and parted it off, but instead I decided to give this a try.  I had to space it out and keep it square so I used (literally) my square and couple parallels as reasonably accurate spacers.  Of course I had the power off while getting it setup!  I was a little concerned about the short grip, but I was able to really tighten it down because the other end will be turned and any marks will be long gone before I'm done.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_101608_zpsg7ktwt3i.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_101619_zpsvgkonjeu.jpg)

As before I turned it down, but this time was shooting for 16mm to fit the other CRS part I made earlier.  I was careful not to overshoot this time.  I stopped as it got real close to fitting (the second photo).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_102815_zpsqj97mq94.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_110144_zpswblcku9q.jpg)

Now I had to go real slow.  I followed a process I've used a few times on this engine.  First turn a portion of the length down an extra thousandth and test for a fit.  If it didn't fit, I'd finish the pass and repeat.  Eventually the other part fits the portion and I know the rest (about 2/3rd of the length) is one thousandth over.   Unlike the brass ring which was ok to be a sloppy slip fit, I really wanted this part to be a press fit with the other part.   Worse case if I screwed up I could glue it up with loctite, but my goal was to press.  And I didn't want to press too thick a fit because the material needs to go somewhere and I didn't want the brass ring, which fits between these two parts, to seize up in the space.  So it was careful work here.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_110419_zpsrbbwgnq6.jpg)

As I've often done on this engine, I finished up the shoulder with my parting tool.  It was ok to run a little extra deep because the inside of this part won't be seen.  I probably should grind an HSS cutter for this work...but the parting tool worked ok.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_112438_zpssijucsod.jpg)

Looking A-OK.  But I can't press it now, of course.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_112522_zpswlupna1d.jpg)

Now I flipped it around to do the eccentric part.  The first step, though, is to turn the diameter to 30mm to match the other half of the Oreo cookie.  We wouldn't want the sides to mismatch, would we?  I used my 3-jaw for this since there is no offset, and of course the 3-jaw chuck was already in the lathe.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_113500_zpsio1bcjom.jpg)

It's time for the eccentric turning and I had to switch to my 4-jaw chuck.  It's a 5 inch chuck and a little big for this lathe, but working good so far.  I centered it first, and then I pushed it for a 3.5mm offset.  That's 138 thousandths of an inch, so my dial indicator ended up at a full turn and 38 thousandths extra (second photo).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_130425_zps21d6ijaz.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_1308172_zpstezwr4bd.jpg)

Next I drilled for the 5/16 inch shaft I'm using.  I thought drilling was best as a start so I can easily see it was offset the way it should be.  The shaft actually measures at about 0.306 rather than 0.313, so I drilled to an N bit and then reamed it to 0.3115.  I figured it wouldn't hurt to be closer in diameter because the 5/16 inch drill bit will probably go oversize.  I'm sure drilling would have been fine.   This was a "what the heck" thing:).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_131531_zps8v6durhp.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_132450_zpswe7371tu.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_132746_zps7cudmwfh.jpg)

And now I could check the fit using the engine itself.  Power is off of course.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_132854_zpsgzlhbhk0.jpg)

Now I started turning down the outer edge.  It was already located correctly so this was just a matter of dealing with an intermittent cut until I got down to 16mm, which was a fairly arbitrary measurement anyway.  That is, it looks nice.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150419_140207_zpsggqr85w8.jpg)

And here are the three parts now.  The new one on the right should press fit inside the one on the left.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150420_213010_zpsexd0goc3.jpg)

The new part needs a set screw to clamp onto the shaft.  I used a 3/16 inch end mill to make a flat, then drilled and tapped as shown in these photos.  I had to use an undersized starter drill to avoid running into the side of the part.  I tapped it using an 8-32 set screw to match the flywheel.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150420_213827_zpsujkxfcub.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150420_214255_zpsvo7lbmfh.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150420_214400_zps0nnymsjj.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150420_214633_zpsypyhfucw.jpg)

Before pressing the assembly together, I needed to drill and tap the brass ring to accept the eccentric rod which I haven't created yet.  I decided to go with a 4-40 thread, even though 5-40 would be better.  I don't have 5-40 taps and dies yet.  They don't seem to be very common, though I do plan to buy a set soon.  I plan to use a 1/8 inch rod which would be a perfect fit for a #5.  But 4-40 should work fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150421_210230_zpsfyvg7q0a.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150421_210435_zpsdtuqxhv7.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150421_210536_zpsulri803y.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150421_210923_zps34d9veho.jpg)

Now for the big moment.  It's time to press the assembly together.  I used my mill vise and as I turned the vise crank I kept spinning the brass ring around to make sure it stayed loose.  It did.  If it hadn't, my plan was to stop quickly and pull it apart before I was at the point of no return.  Well, that was the plan...no proof it would work.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150421_211629_zps0pnphr58.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150421_211722_zpshjvo4vdt.jpg)

Perhaps I should have made the spacing between the outsides a little tighter, but I didn't want to trap the brass ring too tight.  And I really think the brass make it look nice.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150421_211800_zpsrz3cogz2.jpg)

And here it is installed on the engine.   This baby is wanting to run pretty soon now!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150421_212446_zpsjayqbmjw.jpg)

My apologies for the volume of pictures, but I know you guys like to see them, and I thought it's good once in a while to show I really do go through all the steps with starter drills, drilling, tapping, etc.  This build log is for the beginners out there after all.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 23, 2015, 02:06:55 PM
It occurs to me now that in recent posts I've been saying arbor when I should be saying mandrel.  In my copious free time I'll go back and fix those references.

As far as I can tell the word "mandrel" is most used as a shaft that holds spinning work while the word "arbor" is a shaft that holds a spinning tool.  In my case I was holding a flywheel or eccentric disc which is the work.  I know the words are nearly interchangeable, but I may as well get it right for future readers :).

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on April 23, 2015, 02:08:34 PM
That's one handsome engine Todd...can't wait to see it running ...soon as you say!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: Jo on April 23, 2015, 02:21:48 PM
It occurs to me now that in recent posts I've been saying arbor when I should be saying mandrel.  In my copious free time I'll go back and fix those references.

The Hardinge Operator manual uses the term "arbor" to refer to the mounting for the work, so that is good enough for me.

Jo
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 23, 2015, 02:44:53 PM
It occurs to me now that in recent posts I've been saying arbor when I should be saying mandrel.  In my copious free time I'll go back and fix those references.
The Hardinge Operator manual uses the term "arbor" to refer to the mounting for the work, so that is good enough for me.

Well that's official enough for me to use an excuse for avoiding edits when I should be working on the engine! :)

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 27, 2015, 01:35:29 AM
The Eccentric Rod

The eccentric rod connects the eccentric ring, which I made of brass and drilled/tapped for a 4-40 thread, as well as a couple other parts that clamp in a very adjustable way to the valve rod.

I started by making the two clamping bits.  They are each made from a short length of 0.25 inch (6.3mm) diameter rod.  The first is 16mm in length and drilled from the side to accept the other part which will have an end that acts as a pin.  The print showed 3mm and I approximated this with a 0.125 inch hole.  I found the edge and locked the Y as both parts will have centered holes drilled.  It's resting on a single parallel that can't be seen in the photo.  Note that the rod is full length which is easy to work with.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_185214_zpscxueq4o7.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_185636_zpscw4ifpcs.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_185746_zpsi02z5leb.jpg)

Next I chucked it in the lathe to drill and tap 8mm into the end.  The rod is still full length and extending out the back side of the head.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_190520_zpsm8wazsww.jpg)

I don't have DROs on my lathe, nor do I really have a good way yet to measure depth while drilling.  Since the depth of this hole isn't absolutely critical, I used my rule on top of the tailstock like this.  It was a tiny bit easier than reading the 1/16 inch marks and converting.  I'll need to invent something for this sometime this summer.  Maybe a simple battery powered scale will be best.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_190928_zpswnlgbpi3.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_191216_zpsmhc1bxmv.jpg)

I tapped for 4-40 which I'll use on the eccentric rod.  Note that the tap is just resting on the chuck jaws for a guide.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_191615_zpsmxtzbfh1.jpg)

Now some high-tech measuring as prep for parting it to 16mm long.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_192446_zpsyeebl9cr.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_192622_zpsooc0o0xk.jpg)

And that's the first of the two clamp parts.  I should have buffed it a little before parting it off.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_193218_zpsdxciosre.jpg)

On to the next part.    The Y axis was already centered for this rod so it was just a matter of finding the edge of the end and drilling a hole very similar to the previous part.  This hole is for the valve guide rod which I made using 0.125 inch rod a long time ago.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_193739_zpsxfrkeqpf.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_194042_zpsn56rsooh.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_194156_zpseubw5ycq.jpg)

The rod was full length in the mill vise and it remained full length while I chucked it for turning.  I turned the end down to 0.125 to slip fit in the hole I had turned in the first part.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_195712_zps5mhmwtpp.jpg)

Here's the fit.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_195744_zps44zuqkdn.jpg)

Next I turned down the tip slightly to 0.113 for threading with 4-40.  I found later this wasn't really necessary because the die cuts fine at the larger size.  But I wanted the nut to seat without actually holding the second part tight, so doing this with measuring was a good thing.  It probably doesn't matter if the other part is bolted down tight, but when the eccentric runs the rod will swivel ever so slightly so I saw this as a good thing.  At least I probably won't need to loctite the nut into place.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_200050_zpsqkg9ecan.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_200400_zps0pazuk7d.jpg)

Here's the fit.  The nut bottoms out just before it holds the other part tight.  So I can spin that part around.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_200612_zpspsk7jy3s.jpg)

How part it off to length at 22mm.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_205117_zps26ktkjg8.jpg)

I flipped it around in the chuck, this time held with soda can aluminum, faced, drilled, and tapped 6-32 for a set screw.  The drilling goes all the way to enter the crosswise hole so no depth measuring was needed.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_205411_zpsdwzbnbzy.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_205915_zpsyxtvemsg.jpg)

I chuck the 6-32 and bigger taps, but of course I do the tapping by hand.  No power.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_210048_zpsbqw2xwn4.jpg)

Here's the assembly.  The end toward the ruler is tapped for the eccentric rod which I will make next.  The other part has a setscrew so this can be slid onto the valve rod and held tight.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_210741_zpsdtkmuxyl.jpg)

Next, the eccentric rod.  I threaded one end for 4-40 for 10mm.  I have it wrapped in soda can aluminum which is hard to see in the photo.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_213226_zpsjvvsa1zt.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_213307_zpsnaogflx8.jpg)

The rod will be 80mm long, but I decided to bend it next.  It needs a little offset to line up between the valve rod and the eccentric that's already on the shaft.  I used two parallels to do this in my mill vise (photo is from straight above as if you were the mill head).  Maybe that's not the best thing for the parallels, and in fact it would have been nice if the ends weren't as sharp as parallels.  They dug into the rod a little, but otherwise did a great job.  The rod had an offset but was very straight.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_214138_zpsgstzzpgw.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_214216_zpsnh9coizv.jpg)

Now I'll thread the other end and the rod will be done.  I had to do this in my bench vise.  I measured 80mm and cut with a hacksaw and then threaded it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150423_215021_zpscfcgqbss.jpg)

The rod turned out a bit too short.  Here's a photo taken from above while it is on the engine.  The left edge of the ruler is where the valve guide block should be.  I removed the bolt holding that block and it slid all the way over to 8mm.  So I decided to re-make the rod to 88mm since it was so easy anyway.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150424_195520_zps61l1d3bx.jpg)

Here's the new rod without bothering to show the steps again.  I found some shiny rod that looks better anyway :).
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150424_210035_zpstcrpt0wm.jpg)

Here it is on the engine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150424_211035_zpsywo3mp5s.jpg)
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150424_211040_zpscddfayip.jpg)

Almost ready to go.  I need to adjust for the timing and check things over and it'll be about ready for air.  It's a little stiff right now so I hope it loosens up.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on April 27, 2015, 01:51:19 AM
Looking forward to the first running Todd as I'm sure you are too. Some running in should loosen things up and lessen the stiffness. Almost time for the "Happy Dance."

Bill
Title: Re: Pottymill horizontal engine build
Post by: bruedney on April 27, 2015, 03:11:25 AM
Hi Todd

Very nice build - A mill is next on my wish list - makes some jobs so much easier.

Mine was a bit tight too - the fact that the ports at the end of my cylinder were almost completely covered by the end caps did not help the running. It now runs very sweetly on about 5 - 10 psi.

Bruce
Title: Re: Pottymill horizontal engine build
Post by: tinglett on April 28, 2015, 11:19:29 PM
The First Run (!!!)

Well, I can't complain about this.   Oh yeah!  (Cue the Ferris Bueller music)

cZAMqtcaaiA
Sorry about the un-steadycam, but I was pretty excited it just took off so I grabbed my camera.  I took a couple of pathetic short videos, but the air was set at 40psi and my compressor is pretty small and kept kicking in.  So I decided to record a run with the compressor off.  It was pretty cool that it ran down smoothly like it did.  Well, fairly smooth.  It sure sounds like it was loosening up a little as it ran, but perhaps that was my imagination :).

It's interesting having the exhaust ports facing up because I can see a bit of the valve action in there.  Something doesn't quite seem right as the port near the head is exhausting quite a bit more air than the other port.  I need to pull apart the valve and do some measuring to make sure the part is the right size.

But hey, it ran without any real adjustment!   Nice.  And thanks a bunch to Stew for designing AND for happily giving it away for people like me to attempt.

Enough victory speech.  I need to start tuning, but it may be a night to celebrate with a good beer instead!   Thanks EVERYONE for the advice and encouragement.   But this build log ain't over yet...I'll do some tuning and finish work before I place it over in the Showcase.  I still have to mount it to a real base!

Todd
Title: Re: Pottymill horizontal engine build
Post by: Don1966 on April 29, 2015, 01:19:06 AM
Outstanding Todd! Make you proud as a peacock doesn't it? Nice work and nice runner, you may just have to adjust the slide valve some to cure your leak.  :ThumbsUp:

Don
Title: Re: Pottymill horizontal engine build
Post by: Dave Otto on April 29, 2015, 01:28:11 AM
Congrats Todd!

Dave
Title: Re: Pottymill horizontal engine build
Post by: fumopuc on April 29, 2015, 04:29:00 AM
Hi Todd, congratulations, a nice runner.
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on April 29, 2015, 06:07:20 AM
Well done Todd looks and sounds a good runner.

 :whoohoo: :whoohoo: :whoohoo: :whoohoo:

I like how you made the fly wheel.

With your misgivings with the valve events, you may have to centralise the valve travel that's easy done by altering the position of the connector on the valve rod, you may have to thin things down a bit in this area if the adjuster start to fowl the guide or the gland nut.

Just have a play around with it at different settings and one by one ease any tight spots, and just generally let it run in with plenty of oil and just have fun and show it off to your family and friends.

Cheers

Stew
Title: Re: Pottymill horizontal engine build
Post by: Stilldrillin on April 29, 2015, 08:24:22 AM
Congratulations, and well done, Todd.  :praise2:

David D

Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on April 29, 2015, 12:42:50 PM
Fantastic Todd, I love it!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: Roger B on April 29, 2015, 03:18:29 PM
Very nice work  :praise2:  :praise2: The first run always feels good  :ThumbsUp:  :ThumbsUp:   :cheers:
Title: Re: Pottymill horizontal engine build
Post by: mike mott on April 29, 2015, 05:21:22 PM
Congratulations Todd, it is so satisfying when one sees all the effort finally come to the initial test and it works well first time.

Mike
Title: Re: Pottymill horizontal engine build
Post by: NickG on April 29, 2015, 07:07:00 PM
Well done Todd, great workmanship, good runner. Mine is tight too but got looser despite only having very short runs. Haven't had the chance to run mine properly yet as don't have a compressor - will have to convince my dad he doesn't need his any more! I think my valve timing is slightly wrong, noticed the same as you more exhaust from one end - although I guess it will be different as there is less area due to piston rod.
Title: Re: Pottymill horizontal engine build
Post by: Jo on April 29, 2015, 09:17:12 PM
 8)

Jo
Title: Re: Pottymill horizontal engine build
Post by: Kim on April 30, 2015, 04:21:55 PM
Congratulations on a nice runner there Todd!
It looks great!
Kim
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 02, 2015, 10:21:14 PM
Tuning the Engine

I'm taking a break to report tuning efforts so far this weekend.

I removed the valve guide as I thought it might be binding slightly and it could do without it for a while.  I had made a fourth spacer so I could simply replace the guide with the spacer for the cross slide guides.  Perhaps this helped, but not measurable.

I removed the valve assembly so I could more closely study the operation.  I could have figured this out from the plan, but it was easy enough to remove.  First, I found that the valve was made correctly.  The measurements were good.  Second, I found that the position the valve needed to be at the end of minimal travel to allow air to fully enter the cylinder.  Since my valve was mounted upside-down (remember that?) it was quite easy to adjust.

I re-installed the valve and looked straight down as shown in the photo.  Those are the exhaust ports and I'm looking at the one on the right which is near the cylinder head.  It may be hard to see...but that's the thick end of the valve that is obstructing the right exhaust port almost completely.  This is actually a leak.  Air is coming in to the middle of the valve and trying to get into the cylinder, but you can see a gap to the left in this port and much of the air is escaping!  That explains why this port is blasting more air that the other port.  At this point in the cycle, the port on the left is exhausting air.  So the valve is clearly pushed too far to the right.  Easy to fix.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150502_104527_zpsimgafwfa.jpg)

From my experiments looking over the valve chest when it was removed, I learned that the valve should halfway obstruct the exhaust port when it is at the end of its range.  When it is at the end of the range the other port is exhausting and that port will be fully exposed.  Here I have the valve adjusted correctly for end of travel to the right port.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150502_105056_zpswmbm7yan.jpg)

Here is a photo showing the left port when the valve is pulled to end of travel to the left.  I have it going a little too far.  It really shouldn't matter, but I balanced them out a bit better after taking this photo.  The important thing is that if the valve doesn't travel far enough to the end of the range, it won't fully open the internal port into the cylinder.  You can't see that in photos.  Experimenting with the valve chest removed was useful to learn this.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150502_105107_zpsan9m49ar.jpg)

Now it was running ok, but still required a lot of air.  I re-packed the piston guide and the piston.  That helped quite a bit.  The engine actually feels rather silky going around, but I noticed a bit of tightness as the cross slide went to the right.  It occurred to me that the cross slide guides might be binding.  Sure enough!  I loosened the cross slide guides a bit while it was running and BAM!  It starting running on very low air pressure.  Here's a picture.  I kid you not -- it really took off!
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150502_134651_zps1blwpo7c.jpg)

But that doesn't say much, so here's a new video...
5fWvOWqnJhQ
Rather than tweak the guides now, I think I'll start polishing it up a bit and will mount it to a base.  I'll take care of the guides as I reassemble as this is going to mess it up for a bit anyway.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on May 03, 2015, 01:36:49 AM
It sure is running smooth in that latest video. Very nice sound too!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: Kim on May 03, 2015, 02:32:44 AM
Nice... I love watching them run slow like that.  It sounds and looks great!
Kim
Title: Re: Pottymill horizontal engine build
Post by: mike mott on May 03, 2015, 04:57:17 AM
Very nice, listening to that slow steady beat reminded me of my childhood watching trains on the GWR in Acton.

Mike
Title: Re: Pottymill horizontal engine build
Post by: Stilldrillin on May 03, 2015, 10:29:08 AM
That's the way they should be run! (http://smileys.on-my-web.com/repository/Respect/respect-048.gif)

Well done, Todd!  (http://smileys.on-my-web.com/repository/Respect/respect-001.gif)  (http://smileys.on-my-web.com/repository/Respect/respect-001.gif)

David D
Title: Re: Pottymill horizontal engine build
Post by: kev on May 03, 2015, 10:40:59 AM
Nice one, been a real interesting thread this :)
Title: Re: Pottymill horizontal engine build
Post by: NickG on May 03, 2015, 07:23:58 PM
Wow, runs so well, a testament to the workmanship. Are you planning on drilling an oil hole through into the main bearings ? Will be easier to lubricate that way.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 04, 2015, 04:15:34 PM
Are you planning on drilling an oil hole through into the main bearings ? Will be easier to lubricate that way.

I should consider this, but have no real experience doing it.  Would I just drill a small 1/16 inch (or so) hole straight down through the support and bearing?  The bearing is pressed and won't move around, so I think this will work.  How important is the diameter?  I've been using mobile-1 oil that I use on the ways of my machines and it seems to work well for this.

When experimenting with the engine I did find that oiling the main bearings was the toughest thing to do while it was running.  All the rest of the parts were pretty easy to oil provided a think just a little how the engine was going to knock around my little plastic oil "can."  But the crankshaft is pretty unforgiving :).

Todd
Title: Re: Pottymill horizontal engine build
Post by: Roger B on May 04, 2015, 06:24:38 PM
A very smooth runner  :praise2:  :praise2:

A 1/16th hole should be fine for lubrication. If you are not intending to make an oil cup a reasonably large countersink will help to get the oil in.
Title: Re: Pottymill horizontal engine build
Post by: NickG on May 05, 2015, 08:14:03 PM
Yeah, that would do the job IMO - just an easy way of getting oil in there. As Roger says a countersink to hold a bit of oil. The 1/16" hole will probably deliver far more oil than needed and might appear to just run straight back out but at least it's an easy point to oil at the start of a run - guess that's why on large engines you would have drip feed lubricators but think a simple hole will suffice on an engine like this unless you intend leaving it ticking over all day unattended at a show.
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on May 05, 2015, 08:41:54 PM
Todd, I use thinner oil (3 in 1 or Starrett Instrument oil) and for those even a hole as small as say a #60 works fine.

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 06, 2015, 09:58:59 PM
Thanks all, I'll try this maybe tomorrow when I get some shop time.  I'll start with a #60, countersink it, and while it's still in the vise I'll try oil and see how it drips into the bearing.  It'll be a good learning experience.  If I need to drill bigger, it'll be right in place and I'll repeat until it drips nice.

I don't expect it'll really work as a drip oiler, but I do want to test it to make sure some oil actually flows through.  I'd feel a little silly discovering that it doesn't work two years down the road :).

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 06, 2015, 10:40:56 PM
Making the Display Base

I started cleaning up and polishing parts, but decided to stop to make a proper base to re-assemble the engine.   I mulled this over quite a bit and decided to keep the base abstract and make it match my previous simple bases.  That is, nice beveled black walnut.  By "abstract" I mean I wasn't going to try to make model bricks and such.  The model doesn't have that level of detail so the nice wood plus well polished metal should have a nice look.   I need to try the full model approach -- bricks/tiles, lagging and paint -- on some future project.

But first things first.   I still need a way to mount the aluminum base to the wood base.   I decided to keep this attachment blind by drilling/tapping from the underside with 10-32 screws.  Since the plate is only 0.250 inches thick, I used a small 2-flute end mill to drill a flat-bottom hole 0.220 inches deep.  It worked well even though it was slightly undersized for the tap.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150503_152734_zpsqj6opsdd.jpg)

I used a bottoming tap to get as many threads as possible.  I didn't count them, but there are plenty.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150503_153009_zpsontle0az.jpg)

Sorry for the simple tapping photos, but I thought this one was interesting.  It shows the metal curls were heavier than usual due to the undersize hole.  But it worked fine.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150503_153952_zpsgyaa2gte.jpg)

Next, time for the brown stuff.  In this case I used a black walnut block that matched the plate in size and used transfer punches to locate the holes.  This block raises the engine so the flywheel clears the main display base.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150503_154957_zpsnn6xyytt.jpg)

Hmm...I didn't take a photo of what I did with these hole locations I just punched.  I used a 5/16 inch forstner bit in the drill press to drill clearance holes in the walnut block so the screws that protrude from the aluminum plate will clear the wood.  Simple enough.  This could be messy as it is completely hidden, but I have quite a bit of woodworking gear and used it :).

Here I show a similar approach on the opposite side of the wood block using the same drill bit to countersink the bolts that hold the plate to the wood.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150503_161326_zpsarr4fvra.jpg)

At the moment I am stalled hitting the wood base and block with danish oil.  A few more coats and I'll start assembling it this weekend.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150506_160023_zpsdlsej19y.jpg)

Now I need to get back to polishing the bits and re-assembling the engine.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on May 07, 2015, 12:22:48 AM
A very fitting base for a lovely engine Todd. Well done!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: Heffalump on May 08, 2015, 10:24:00 PM
Wow, simply fantastic Todd. I've just read the entire thread as I've started to build this engine. I was really impressed with the first video, but when I saw the second... wowie! To get an engine that looks that good an runs as slowly as that is a dream, and the sound is fantastic! I hope you're very proud. Well done, I can't wait to see it all polished up and stood on its base.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 09, 2015, 02:51:09 AM
Well done, I can't wait to see it all polished up and stood on its base.

Thanks a ton for the encouragement!   I spent quite a bit of time in the shop this evening polishing away.  I only hope to get 1/100th the shine that Don manages to produce (maybe he'll do a "polishing log" for us someday!), but even so the parts are looking pretty good.  It's completely disassembled right now so I hope I can get it all back together again.  I'll take a picture of the parts, too.  It's quite a "kit" right now.

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on May 09, 2015, 03:48:51 PM
Todd, there was some discussion in Don's Eastern & Anderson thread as to finishing, wasn't sure if you had seen it or not. You can find it here and it continues off and on for a few pages.

http://www.modelenginemaker.com/index.php?topic=4629.msg90113#msg90113

Start with reply #104

Bill
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 10, 2015, 12:35:21 AM
The Kit of Parts

I just finished polishing and making the base.  Here's what a kit form of the pottymill horizontal engine might look like.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150509_180943_zpsspv7rlxg.jpg)

Fortunately, a lot of those parts are fasteners.  Even so, there are quite a few parts and it was fun making every one of them.

I had generally sanded most of the parts through the grits to 320 and stopped.  I probably should have gone further, but I was mainly looking to remove the bigger scratches.  I'm not shooting for a mirror finish, but I'd like a shine on a few of the parts and especially the flywheel since it turned out so nice.   I polished with a hard(er) wheel and green stainless compound first, and then hit the parts with a soft wheel and blue all-purpose.  I probably should have started courser, but thought I'd see what this would do first.

Two things caught my attention.  First, the base was really getting a mirror finish and I decided I didn't want that because it was so large and flat and would distract from the rest of the engine.  So I brushed it with a fine wire wheel and smoothed it out with green pad.  Now it's just ordinary aluminum.   Second, the shaft supports had a rather nice looking finish direct from the bar stock that I thought was interesting, so I only polished the edges.

Now I need to put the thing back together and get it tuned back again.  That should happen over the next few days I hope.

Todd
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 10, 2015, 12:37:14 AM
Todd, there was some discussion in Don's Eastern & Anderson thread as to finishing, wasn't sure if you had seen it or not. You can find it here and it continues off and on for a few pages.

Bill, yes I followed that with great interest.  It really reminded me how little I know about polishing.  There are new things to learn every day!

Todd
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on May 10, 2015, 12:53:25 AM
That's a great "exploded" picture Todd. I really do like this engine!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: zeeprogrammer on May 10, 2015, 01:16:07 AM
Fantastic family shot. Very nice.
Just watched the video. That is one great sound.
Title: Re: Pottymill horizontal engine build
Post by: steamer on May 10, 2015, 12:49:59 PM
Sweet!!
Title: Re: Pottymill horizontal engine build
Post by: rodw on May 12, 2015, 04:38:45 AM
Awesome work. Been following this build religiously and I dont often do that.
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 13, 2015, 04:07:29 AM
More Tuning

I've disassembled the entire engine (you saw that earlier), gave it a bit of polishing, and am in the process of reassembling and tuning as I go.  It's slow going.   I reassembled it completely and it was mighty stiff, so I backed off and am working on it component by component.  Here's what I've learned so far.  All of the problems so far are my own making.  Oh well, I'm learning as I go.

Here is one of the first things I noticed, and I noticed it earlier as I assembled the engine.  The valve chest is just a teeny bit oversized so it's pushing the cylinder head away from the cylinder.  That's causing a leak.   I had pulled the cylinder/valve mechanism (shown in the blurry photo -- sorry about that) off the engine, gave it compressed air, and was working the valve manually with my fingers.  The piston would snap out, but wouldn't snap back in.  The problem is this leak as far as I can tell.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150511_140038_zpst7mcyzxy.jpg)

I removed the valve chest and skimmed 3 thousandths off the end on the mill.  I did this by cranking the mill into the chest until it started cutting and went an extra 3 thousandth of an inch on the dial.  No fancy measuring.  That seemed to be enough.  I didn't take a picture of it.

The next thing that was really bugging me had nothing to do with tuning at all.  As I removed and tightened bolts, I kept scratching up the aluminum in a way that was really difficult to polish.  When I'd polish over the bolts it would create ugly "shadows" (not sure how to word this).  I needed a way to tighten/loosen these bolts without scratching up the works.  I came up with the technique shown in this photo.  I first tried to put electricians (plastic) tape on my wrench, but that didn't work well, so I punched the tape with a paper hole punch and applied it.  I reused this many times and it held up fine.  It gummed up the aluminum a little with stickiness, but that was easy to remove with a little oil.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150512_193237_zpszsagugvy.jpg)

Now I simply had a stiff engine, and it wasn't clear at all what was making it stiff.  So I started disconnecting stuff.  Step 1 was to disconnect from the crank and make sure the flywheel assembly turned smooth.  It did.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150512_200035_zpsd7wyiuwu.jpg)

The crosshead guides were binding.  I could loosen them and it would work better.  I'd test this by sliding the cross head manually since it was no longer attached to the crank.  So it was time to skim the slide bars.  I took off 5 thousandths from both top and bottom.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150512_201026_zpsqens3gmt.jpg)

This helped, but it was still binding.  I removed the guide on the valve side of the engine and it loosened up a lot.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150512_201942_zpslrxyglob.jpg)

It turned out the slide bars weren't at fault for the binding on the valve side.  It was the brass thrust washer.  I happened to have one that was a few thousandths thinner, replaced it, and now that was working well.  It goes to show you that you should save your "junk" parts until the build is finished.  I had made this thrust washer as a test part and thought it was too thin!

By the way, another useful thing was that it was very handy that I made the temporary pine base you see clamped in the vise.  It held the engine and it was ok for me to get oil and other gunk all over it.  Otherwise I'd be messing up the nice black walnut base you saw in an earlier post.

Now the engine was cranking fairly smooth by hand.  A little stiff, but not too bad.  When I applied air it took A LOT of pressure to make it run.  I was at over 50 psi.  The energy was going somewhere.   Now, this is fairly high pressure, but I discovered the cylinder was leaking when I dribbled a little oil on it.
(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150512_204745_zps98kp0vvx.jpg)

In the plus column, the rear cover is solid.  No leaks I could find.  but both the valve chest and the front cover are leaking pretty bad.  I need to figure this out.

I'll probably re-do the piston rod packing, and maybe re-pack the piston as well.   The valve is a bit leaky too, but then again I'm applying a rather serious amount of air pressure at the moment.

Todd
Title: Re: Pottymill horizontal engine build
Post by: sbwhart on May 13, 2015, 07:26:58 AM
Hi Todd

Good work with the fine tuning step by step is the way to do it.

As for the leaks arround the valve chest all you need is some silicon sealant Hylomar or some such product you'll get it from your car spare shop.

Hope this helps

Stew
Title: Re: Pottymill horizontal engine build
Post by: Jo on May 13, 2015, 11:14:39 AM
Sealants: I was recommended to use Wellseal, rather than a silicon sealant which have a nasty habit of going hard in the tube  >:(.

Todd, I can't remember, :old: have you used gaskets to help the seal?

Jo
Title: Re: Pottymill horizontal engine build
Post by: Jasonb on May 13, 2015, 12:59:31 PM
I use a blue instant gasket from Halfords (car accesory chain store) which is a silicon base, had the current at least six years and it was still working fine last week.

A washer under the nut will save your tools making themetal/paint.

J
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 14, 2015, 05:27:45 PM
Thanks for all the advice!  For some reason a gasket feels like cheating.  I suppose I get this thought because the surface area of contact is rather large on these parts, and if the surfaces are good it seems that it should be enough.  But maybe I'm just being a bit naive :).

I'll double check the surfaces are reasonably tight first.  Maybe I have a burr on a screw hole or something like that.  I did change the fasteners on the valve chest from philips head screws to hex head "bolts."  It's possible I'm not getting them as tight.

Jason mentioned washers and it's interesting that I thought of that, but don't have any in these teeny sizes.   I see microfasteners has some, so I'll add that to my list.  Not sure why I didn't look for them when I got the bolts.  But a "real" engine wouldn't have washers in these places, would they?  I'm trying to think through in my head why they'd use them.  Maybe I need to look at some photos.

I'm off to run full size steam traction engines this weekend so my build will pause for a bit.  But I'll be having a different kind of fun, and I could look at how parts are bolted together.  Maybe I should be using studs in some places as well.

Todd
Title: Re: Pottymill horizontal engine build
Post by: NickG on May 14, 2015, 07:13:12 PM
A real engine (I would have thought) would have gaskets and washers Todd. They help spread the load.
Title: Re: Pottymill horizontal engine build
Post by: rodw on May 14, 2015, 08:22:11 PM
A real engine (I would have thought) would have gaskets and washers Todd. They help spread the load.

I'm sure gaskets would have been used too. As a kid in the bush where life depended on several stationery motors from the early post steam era, I can assure you that gaskets were everywhere. For some applications we even made them from leather. We used to use some gasket goo pre silicone era which you can still get from a bearing shop and it was kinda strange to go naked via a smear of silicone in later years. Just be careful that you don't use too much silicone so it builds up in the inside, vibrates off and blocks the valves. I had this happen when I had a Weber carby fitted to a car years ago and the excess silicone on the air inlet side blocked the carby after a few days. The boss was very cranky with his mechanic....

I might be proven wrong but from this experience, I'd be tempted to use goo and you'd be more authentic too!
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 22, 2015, 02:07:05 AM
Wrapping it up!

It's time to wrap up this build and put it up for show.   I went with gaskets today.  Since I didn't have silicone, I decided I'd try paper.  I had some vellum which I found was only 0.002 inch vs. 0.004 for my ordinary printer paper.  I applied some oil to make it "stick" (this worked well) and it looked like this:

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150521_175622_zpsybxv2ukd.jpg)

I assembled the cylinder and valve mechanism and tried applying air before I put the whole engine back together.  I had the air on with a rather high pressure (50 psi) and the thing nearly jumped out of my hand when it snapped!   I squirted a little oil around and found I still have a very slight leak at the bottom of the front cylinder cover, and a teeny bit leaks at the corner where the front cylinder cover meets the valve chest.  I'll leave it for now.  Next time I'm at an auto parts store I'll look for something appropriate and if I ever need to take it apart I'll apply it.

Here are some pictures of the assembled engine.  It's running fine again, too.  I'll get the video uploaded and do a final post over in the showcase.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150521_194425_zpspn0ko5yl.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150521_194526_zpsfh0mr3ob.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150521_194540_zpsvex6otcd.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150521_194610_zps9bi32kxs.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150521_194627_zpsthrnid86.jpg)

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150521_194357_zpsdz4imxhn.jpg)

I'm pretty proud of it.  A nice engine and a super-thanks again to Stew for designing it and sharing it with me!

Todd

P.S.  According to photobucket I have taken 1134 photos for this build.   I know you guys love photos, so there ya go....
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on May 22, 2015, 02:14:16 AM
Beautiful result Todd, and excellent pictures too!!  Well done.

Bill
Title: Re: Pottymill horizontal engine build
Post by: Jo on May 22, 2015, 09:09:34 AM
Nicely done Todd  8),

So, what is next  :mischief:

Jo
Title: Re: Pottymill horizontal engine build
Post by: Mike Bondarczuk on May 22, 2015, 09:14:33 AM
An inspirational build Todd  :ThumbsUp:

Many thanks for the progress reports and pics and certainly now moved much higher on my build list.

Looking forward to seeing the next one.

Mike
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 22, 2015, 12:23:29 PM
Here's the link to the showcase:  http://www.modelenginemaker.com/index.php?topic=4966.0

And here's the video so you don't need to look :)  If you've followed the build you've seen the photos I posted over there.
TnJRCVVy86w
Jo asks what next...and yeah, that is on my mind (why is that? :)).  I'm really not sure at the moment.  I might do one more bar stock engine before trying castings.  But I have a few shop projects to do after I clean up some of the mess I created in the shop.  I'd like to make a carriage stop, maybe some soft jaws (for lathe and bench vise), a mod or two to my "new" bandsaw, etc.  I also need to adjust my mill's Z axis.  I made a list of "problems" to fix during the build.

So meanwhile I'll be skimming prints, magazines, and books for engines and will be dreaming.   The only thing I can say is that the "Wall Engine" by Roy Ozouf is growing on me.  It's a weird little engine and is in his "Three Elegant Oscillators" book which I immediately bought when kvom started the Coventry build.  It's beyond my skill level, but I'm ok to push to the next level!

Todd
Title: Re: Pottymill horizontal engine build
Post by: cwelkie on May 22, 2015, 02:32:52 PM
Nicely built and presented Todd.  You are well on your way.
It is interesting how a list of things to do and tooling to make grows with every build ... all part of the fun.
Title: Re: Pottymill horizontal engine build
Post by: NickG on May 22, 2015, 08:03:02 PM
Brilliant Todd, well done. What are the three elegant oscillators like? Are they bar stock?
Title: Re: Pottymill horizontal engine build
Post by: fumopuc on May 23, 2015, 04:18:26 AM
Hi Todd, nicely done. You have shown an informative build report with very good pictures. Thanks for let us following step by step on your way. Waiting for your next project.r
Title: Re: Pottymill horizontal engine build
Post by: tinglett on May 30, 2015, 01:40:38 AM
Labeling it

Ok, one more minor update.  As I was making my walnut bases for my engines, including the base for the Pottymill Horizontal engine, I left room for little trophy plates to label the engines.  This was my fourth build so I decided it was time to order some.

I decided to go with trophykits.com.  Their web page looked easy to use and the prices are dirt cheap.   The first three engines had room for 1" wide by 4" long plates, and the Pottymill engine could use a much longer plate, but I went with 5".   I sent rather picky instructions that I'd like the fonts to be big and match across the four plates if possible, and asked if they could please right justify the year and left justify the engine name.  Well, damn they got it exactly right!   And for only $2 USD per plate.   It took 5 days, but here they are...spif!

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150529_130208_zpsvyahazvi.jpg)

They came with double stick tape already on the back, so here they are on my set of engines.

(http://i1067.photobucket.com/albums/u435/tinglett2000/Pottymill%20horizontal%20engine/IMG_20150529_193007_zpsfvgdb4ru.jpg)

How cool is that?

Todd
Title: Re: Pottymill horizontal engine build
Post by: Dave Otto on May 30, 2015, 01:52:30 AM
Nice Todd!

If I could build 3 engines in one year I wouldn't know what to do! My projects are measured in years not months.


Dave
Title: Re: Pottymill horizontal engine build
Post by: b.lindsey on May 30, 2015, 01:58:47 AM
Those turned out very nice Todd. I will keep that link in mind!!

Bill
Title: Re: Pottymill horizontal engine build
Post by: gary.a.ayres on September 19, 2018, 11:04:47 PM
I have just read this thread from start to finish.

Very full and transparent description, and beautifully photographed, resulting in an immaculate engine.

I plan to have a go at this engine once I have a couple of oscillators under my belt. Only one thing, though - I don't share your love of maths so when it comes to the flywheel I'll be using dividing plates   ;)

gary