Author Topic: Newbie building a PMR 6CI  (Read 8899 times)

Offline vdubjunkie

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Re: Newbie building a PMR 6CI
« Reply #75 on: August 05, 2018, 08:59:30 PM »
Looking really good - you've about caught us up to real time. Looking forward to seeing the engine continue to take shape.

Thanks prop.  Yes, in fact my next post will be the last of the images I have downloaded to the computer.  While a lot of the parts look "complete," I've got to go back and actually complete quite a bit, never mind fixing more mistakes than I'd care to admit.

“It is difficult to get a man to understand something, when his salary depends on his not understanding it.” - Upton Sinclair

Offline vdubjunkie

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Re: Newbie building a PMR 6CI
« Reply #76 on: August 05, 2018, 11:08:08 PM »
The week of 7/15/18 saw some part review and work on a new part.

I finally got the parts together so I could hone the cross slide.  Here is a piece of PVC getting ready for me to turn it into a honing tool.



You don't see much of the PVC at this point.  Much like rcdon described, I taped some paper to the pipe, observing the rotational direction, and added more sheets as necessary to bring the sandpaper out to a functional diameter.



Not having created the cross head yet, 1.502 tells me exactly where I need to be when turning the head.



Now that I know where I need to be on the head, we can begin to machine it.



With the base of the head already finished to dimension, after machining out the flat here, I was able to accurately place the hole.



Here is a better picture of that hole after drilling the size under the 5/16" reamer.  The part is coming along nicely.



If you look closely, you'll see my center mark, but also I have scratched in the diameter for visual reference.  You can see that the cast was a bit off, but there is plenty of material.



This may be an effort in vain, but I thought I'd remove some more of the material on the big end of this rod.  It's just fun too!   :LickLips:



If you look VERY closely, you'll see a little bit of light between the square and the part at the top.  Somehow, I was not machining squarely.  When I realized this, I took a closer look at my setup in the vise.  I was placing the part on top of a couple of tool blanks so I didn't yet have to purchase parallels.  Even though I ultimately realized that there is a very small amount of variance in width from one to another, that was not the issue either.  It seems the top of the head was not perfectly parallel to the bottom.  So, when I set the part in place, all looked well.  However, when I clamped down, a small gap formed between the top of the part and the tool blank beneath it.



Using my height tool, I determined the variance, and found that the tip of a razor blade was about the right width.  I could not find my feeler gauges.



Here I am proving it to myself.



I was on a good path.  I also decided to use this fly cutter.  Unfortunately, I did have some issues with it, but other bigger issues became more important.  Rather than simply set off on this path and trust all to go well, I continued to check and adjust as I went.  Later I found something better to use than the razor blade tip (not shown) and got the part to square.



This is such a huge moment for me.  I have been so excited to mount this head to a thread, mount it in the lathe, and turn the outside to dimension.  The part is such a unique departure from other plain turning of cylinders.  Here is a cylinder with the sides cut off, but even more interesting than that.



I found a piece of aluminum rod to use and by the end of the week, I was able to turn it into my mandrel for turning the cross head.



“It is difficult to get a man to understand something, when his salary depends on his not understanding it.” - Upton Sinclair

Offline b.lindsey

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Re: Newbie building a PMR 6CI
« Reply #77 on: August 06, 2018, 01:24:06 AM »
It's been a great journey so far, and now looking forward to even more in real time.

Bill

Offline vdubjunkie

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Re: Newbie building a PMR 6CI
« Reply #78 on: September 03, 2018, 04:10:33 PM »
Never fear!  I have been slacking with posts to the forum, but not as much with effort in the machine shop.  I still have trouble calling it a machine shop.  It's really a complete mess of a space where a very small third car could get parked in theory.  But, I digress..

Over the past few weeks, I've had some pretty exciting developments and one major point of frustration.   :Mad:

Basically, I'm down to fixing stuff I screwed up earlier, improving fit and a handful of final parts, etc waiting on funds.  I got in the replacement pillow blocks for the engine and got right to work beginning by giving them a few good reference surfaces.



These babies will come down to 1.375", so I've got plenty of material left.  I have learned THE HARD WAY not to get too material removal happy to early.  Have I already mentioned how life changing this height gauge has been for me?



Ok, now that we have both pillow blocks and pillow block caps "to dimension" it is time to layout marks for drilling.



It's a little difficult to see the mark in this light, but you see I've used a machinist's square to ensure the part is perfectly vertical before making my scribe.  Otherwise, precision is just a word with no real effort.  Heck, even with the effort, precision feels like a loose term to me at times.



I took my time, found what I wanted to be my center reference points and scribed 2 cross hairs on each part for the two bolts which will ultimately hold the pillow block cap to the pillow block.



Here is a better view of the sharp pointy object efforts.  With all 4 holes drilled for each pillow block assembly, it was time to get references for the 4 mounting holes in each pillow block.   :embarassed:  What, there are only 3 holes in that picture?  Oh yeah..   :facepalm2:  Despite all my efforts, the fourth hole did not get started in the right location.  So, no problem!  I'll drill it from the bottom.  Problem solved!  ...or so he thought..



I'll kill the suspense here.  That fourth hole, when drilled from the bottom..  Well, it too did not get started properly and I decided it would be better to fix it from the top.  I used some "quick steel" a friend gave me to fill the divot flush and try again.  While the "quick steel" didn't ultimately provide a solid surface as I had hoped, I was able to use a larger sized center drill to sort of force the hole where I wanted it and all was well.

Now was the time to transfer those holes from the blocks to the caps.  This will be the second time I've used cynoacrelate glue, then remove with heat. 



I used my height gauge and squares to ensure the pillow block was properly perpendicular to the drill before I began hogging out the hole. 



With a hogged out hole in place, it was time to bring in the big guns.  I was only able to get a 7/16" hole as my 1/2" was just too long!  Oh wait, I can't fit this boring head.  The Z travel on this machine is pretty limiting.  It provides opportunities to get creative.  For this, the only creativity was to stop using that vise and get closer to the table.



If you look closely, you'll see a machinist's square and a feeler gauge peeking out from under the "top" (sideways) of the pillow block.  If you recall from a previous photo, the edge where I am drilling is stepped in from the edge of the base of the block.  I needed to build up a shim here.  I used my height gauge to find the difference between the two and my calipers to ensure it was the right amount.



Here I am performing a final sanity check.  Ultimately this hole will accommodate a 3/4" bronze bushing, but I need to "sneak up" on that dimension "in situ" when the pillow blocks are mounted to the base to ensure concentricity in the final holes.  So, .742" is perfect.  Later, I'll learn that I can simply unscrew my boring head from the shank and get it out of the way for much more reasonable bored hole dimension sanity checks!   :old:



Here is a shining example of one hesitation I had about sharing my progress with anybody.  You'll notice, that despite my efforts, this hole is not centered in the casting.  It is centered relative to the mounting holes, just not the casting.  I'll likely adjust this later.  Ok, at least this hole is the diameter I want.



Here's a look down my fresh hole.  Without sharing too many pictures, I'll explain how I had to adjust to make this work.  The boring tools I have are several different lengths.  I had to begin with a short one, because a longer one would not have enough Z axis travel and would have to begin down in the hole.  That obviously won't work.  So, after getting .9" down in the hole with the shorter tool, then I was able to use the longer tool to get the rest of the ~ .4".  It was a bit wacky, but totally worked.  Naturally, this wouldn't have been a reasonable way to take the hole to final dimension.



Ok, so that's two pillow blocks ready for final reaming in situ.  By the way, the first of the two of these took over a week to complete.  This improved as I figured out my process better.

I forget if I mentioned it before, but this crank pin had a minor issue.  Minor issues on bearing surfaces are pretty major.  I realized that the parting tool I used to "finish" the bearing journal in the center was not precisely square.  This left one end of the journal ~.002" larger diameter than the rest.  Naturally, this is no way to fit inside a rod cap.  Also, it seems the hole in the rod was not quite big enough.  I used a piece of rod I had happened to turn down to a very nice size for this purpose, and wrapped some fine sandpaper around it, then honed out the hole a bit.  Little by little with frequent testing found a very nice fit I think.



That wouldn't be the only fitment issue on this rod.  The other end was binding a bit on the cross head.  I had to adjust both the rod and head to get this right.  Again, small efforts with regular checks is the way to go here.  Also, when you check the fit, rotate more than just a few times, or you can easily go over your dimension.



Now, I don't have a cylinder center finder tool, so I had to improvise.  I'm not patting myself on the back too much here.  I've seen about 15 different ways to "find the center" from other people, and this wasn't that complicated.  Here, I'm using my height gauge and a magnifier to twist the part where the "bottom" of the hole is at the lowest possible place.  This helps to find my perfect vertical.



The v-block is 1.462", so set my caliper to .731" so I can find my horizontal center.  If I were to set my square 90 degrees of this direction (as I would tend to want to do), there would be a gap between the work and the edge when I scribe my line.  Instead, I went straight on and held everything rigid.  I used a big heavy block of steel with another square up against the side of the v-block so I could get my caliper in there well with enough space to scribe the line.



With the line scribed, I was able to put the part in my vise and compare it to the square to ensure I'm drilling as I intend.  I had put some dykem on the top of the journal, and intended to slowly raise the table until the cutter barely began removing dykem to find my center.  However, I found an easier way.  After using my edge finder on the front of the part, I put my center drill in the machine and pushed the Y axis back .1" (half the width of the edge finder) and used my magnifier to see when the center of the drill was directly lined up with the line at the top of the edge.



With this done, I continued to move the Y axis of the table half the width of the part for that center.  Bringing the table nearly as far forward as possible made it impossible to see the mark I needed once I got there.  The web of the handle was in the way, never mind the vise and table hovering over the top of it.  I was reminded of the ability to line up 90 degrees clockwise around the machine.  So, I took the position to .020" before where I needed (I could still see the marks on top at this point), reference the scale on the side of the machine, subtracted twenty, and voila!   :cheers:



With a #25 drill in use, I completed the hole for this grub screw.  Life is good.  Wait, I couldn't be done just yet.  Everything is going soooo well!  Let's get the tap and begin turning it, using a collet to keep it vertical.  Yes, the collet does cover the square at the top of the tap.  I used pliers to carefully twist until I had a decent beginning to thread bite on this tapered tap.  It was good enough and worked well.  I was able to remove the part from the vise and use a hand tap to keep things going.

All along the way, I turned the tap back well beyond where that last twist began, then forward another 1/4 turn before repeating the process again.  I also used cutting fluid along the way and took my time.  All was going so well..   :hellno:  Then, SNAP!  OMFG.  The tip of the tap was well through the bottom of the hole and I now have a broken tap all the way from the top to the bottom of this hole!



“It is difficult to get a man to understand something, when his salary depends on his not understanding it.” - Upton Sinclair

Offline Kim

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Re: Newbie building a PMR 6CI
« Reply #79 on: September 03, 2018, 05:57:53 PM »
...  I still have trouble calling it a machine shop.  It's really a complete mess of a space where a very small third car could get parked in theory. 
Sound like a shop to me!  :ROFL:

You've done a lot of work here!

Sorry to hear about the broken tap.  I have certainly been there, done that. And it is no fun!  :Doh:

If the tap is through the hole, can you gently screw it out of the hole?  You have to be REALLY careful - the tap is very brittle and will break off quite easily while doing this.

There's also the old Alum trick that I've used before. Not sure it will work with cast iron though.
Depending on the size of the tap, there are tap removers that will reach between the flutes of the tap and help you twist it out.  I've never broke a big enough tap for that to be an option.  Its always  a teeny-tiny one.

If it wasn't a casting, you can always start over again as a last resort.

Good luck getting it out.
Kim

Offline b.lindsey

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Re: Newbie building a PMR 6CI
« Reply #80 on: September 03, 2018, 06:37:15 PM »
Great update and a lot of progress as well. Castings can be a challenge at times.

Bill

Offline zeeprogrammer

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Re: Newbie building a PMR 6CI
« Reply #81 on: September 03, 2018, 06:49:59 PM »
Great update and kudos for sharing both wins and boo-boos.

Bummer on the tap.

The eccentric looks like steel?

Unfortunately I can't help with tap removal. I've only done it on aluminum (with alum).
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Zee-Another Thread Trasher.

Offline gary.a.ayres

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Re: Newbie building a PMR 6CI
« Reply #82 on: September 05, 2018, 10:46:52 PM »

I love that #0.  I remember seeing it while learning about the Burke mills.  I can definitely see how it's even more limited though.  I hope it is serving you well.

I've been looking around at what would be involved to get into a bigger South Bend.  While I could get a newer quality machine for a similar cost, I just love the beauty of the South Bends. 

I also find myself very interested in how and why things are where they are.  The history of our world is just so fascinating!   :old:

Hi -

Wow, it's a small world!

TBH I haven't used the '0' so far. I am planning to convert it back to flat belt as I am building a lineshaft at my workshop in France and aim to hook the Burke and  some other appropriate machines to it when it's ready.

You are right about history, and what a gateway into it this machining  thing is!

Still loving your pics of the #4 - they have a classy look to them.

Also great seeing your PMR develop...

Cheers,

gary

Offline gary.a.ayres

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Re: Newbie building a PMR 6CI
« Reply #83 on: September 06, 2018, 06:36:10 AM »
PS: drag about the tap though. A heartsink moment...

 :(

Offline vdubjunkie

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Re: Newbie building a PMR 6CI
« Reply #84 on: December 29, 2018, 03:01:27 PM »
It's been a while since my last post, and while time has been scarce overall, I have accomplished a few things.

I learned by watching Keith Appleton that one could fix imperfectly created holes in their cast iron base by plugging the holes with cast iron rod, using loctite.  So, I decided to give it a go.  However, to say I have a limited budget would imply that I have a budget.  I have the opportunity to spend some money randomly from time to time.  So, rather than buying cast iron rod, I cut up some "scrap" pieces I had in the shop.



After making rectangular lengths, I center drilled each end on my little milling machine



Without proper lathe dogs, I had initially set out to make my own, but quickly decided to go this route instead.  These two aluminum chunks are an old tap handle arrangement I inherited from my grandfather.  It was tough deciding to put them in harm's way, but I'm certain he would have been happy to see me putting them to use for whatever sensible operations.   :agree:



Next, I used some t-slot clamps to create the force on these handles while turning in between centers.  These things have to become cylindrical somehow!



There's a bit of progress.  It wasn't without bumps and bruises  :wallbang:, but I was able to turn all of my plugs like this.



A test fit in one of the holes goes well, and now it's about time to start chopping this up.   :cheers:



My slitting saw was able to produce perfectly reasonable results in cutting my plugs to length.  This was not the quick way to resolve the issue, but it was coming together nicely.



With my first hole plugged, everything is looking quite nice.  I think all may just turn out ok in the end!



More plugs installed, and the loctite I chose was 680.  It's a bearing retainer.  I thought this sounded perfect.



With the great failure in tapping my eccentric, it was time to make another.  Again, being as cheap as possible, I chose to see if I could use the last bit of 1 - 5/8" round stock provided in the kit.  I would not recommend this to others, but if nothing else, it was a nice learning experience.



Things were going along pretty nicely actually.   :???:



Everything being very disjointed, and trying to meet my mark for having something meaningful to show at our New Year's Eve celebration, I put back together my horizontal milling cutter and cut some keyways into crank rods.  Here's a before next to after rod for illustrative purposes.   :)



This next one could require some explanation for those familiar with the model.  Since I overshot my .002" undersize bore on the crank disks, I can perfectly fit 5/8" rod through the center of these babies.  This allowed me to set the crank pin in place perfectly aligning the crank disks while the loctite cured.  Why did I use loctite I hear you collectively wondering?  Remember how I overshot the bore on the crank disks?  Well, I overshot the turning operation on the pin as well.  Worse yet, this was my second attempt, so rather than make a third, I decided to see if bearing retainer will hold.  If not, I'll rebuild it later!   :Mad:



Now is the time for the return of the aluminum handles tap wrench.  These little threads are so adorable.  I just loved cutting these holes.  You may notice I placed the upside down tap guide over one of the holes to illustrate how I used it to assist in the creation of these threads where I didn't have a large enough flat surface to use the other side.



Here is the bottom of the cylinder, freshly cut holes with "close" nipples installed.  See how freaking cute those things are?  This is temporary, as I'm just not ready to machine the tiny globe valves any time very soon.  I'll be cutting down some brass rod into threaded plugs for these holes, and returning to the globe valves later.



It took a while, but I was able to spend a little money, and pick up some brass rod to make the piston rod.  This looks like a sound operation, right?  Hold rod in 3 jaw chuck, and use tailstock die holder to cut threads.  What could go wrong?



Things are really starting to come together nicely.  You may or may not be able to tell, but that piston rod got gouged up a bit.  As it turns out, it's not the end of the world.  I had to remove a bit of material for it to have the appropriate fit through the gland nut anyway.  No matter how I try for perfection, I'm constantly being reminded that there is no such thing.  I'll just keep getting as close as I am able, and <zen breathing> keep pushing forward!   :rant:



Everything coming together pretty nicely, we now have the piston directly connected with the cross slide via the piston rod.  This was a bit tight at first, and I wound up realizing that it helped to back off the gland nut just a bit.  Then, after a touch of oil in the cross head, a few passes back and forth made me a believer.  This thing will work!



Here came a real treat.  You may notice my shop seems much more substantial.  No, this was time spent at my friend's shop.  He graciously allowed me to spend the afternoon on his "real" milling machine.  Holy crap.  Do you see how I can just clamp the entire base?!   :LittleAngel:

The reality is that my single t-slot machine really cannot allow me to get a consistent finish on the base, so I finally accepted the need to use a larger machine, and took up the offer to use the space.  I'll be returning later to use his press, and who knows what else.  I started my time there by getting the bottom of the base nice and perfectly flat!



With that quickly knocked out, it was on to making the top perfect.  Nothing was WAY out, but I needed to knock down the plugs sticking up from the surface, and there was maybe .015" difference between the highest and lowest spots.  Again, not WAY out, but way too much.  This was a necessary upgrade to my operation!



Just look at those results.  I decided one of the 12 holes was in a good location, so I only had to mark and drill the other 11.  I have no pictures of this, but I taped together two 8.5" x 11" pieces of copy paper, and detailed out the hole pattern.  Then, we used a bit of spray adhesive to position it on the base before using a center punch.  I took my time, and this turned out very nice indeed.



Ok, you guys are getting the good, bad, and ugly here.  While this all went pretty well, 4 of my 11 new holes were not up to the task of being drilled and tapped.  The holes I plugged were sometimes way off, and other times, barely off.  Sometimes the plug held fine, and others, not so much.   :Mad:

I do have a plan B.  Enough time had passed, and I've ordered some cast iron rod.  I know, it seems like only a paragraph ago when I said I wasn't going to buy any.  Well, that's true, but in reality it was a couple of months or something.  Still...!   :wallbang:  So, I'll drill out larger sized holes in the base, tap the holes, and cut threads into the cast iron rod plugs.  Then, rather than using a perfect cylinder slip fit with loctite, I'll be installing them with loctite on threads.  I do believe this will wind up working rather well.



Even though my crank isn't complete, and I only have one screw for the right pillow block, I just wanted to get this all put together, and make sure the relationships looked good.  I believe they do. 



I was actually able to make a short list of every remaining step, and put an * next to those items I can actually do with what I have.  I decided to make the piston rings.  They are far from perfect, but should be plenty effective.  However, my piston is such a beautiful fit in the cylinder, there isn't much room for them.  It is a very tight fit with the piston rings installed.

I need to determine whether there isn't enough clearance between the piston and cylinder wall, or if I need to cut my piston ring lands a bit deeper.



One other thing I could do was to cut gaskets.  Heck, I was even able to do this in the house!  You'll notice they are certainly not perfectly round holes.  I used a compass to mark them, but then had to freehand cut them with a razor blade.  I just cannot go purchase every tool it would take to make everything "perfect," so I made the decision to allow these to be ugly since they will still be plenty effective, and won't show!



Finally, this is a pretty bad picture, but I decided to figure out a way to use my first eccentric rather than the replacement.  The mating between the first eccentric and the yoke is just SO DARNED PERFECT, and also, the replacement wound up being dished on one side where I failed to take a really good look before getting started on the operation.  One of the employees at my friend's shop suggested a 1/4" carbide end mill with a VEEEEERY slow feed.  This worked perfectly, and my broken tap was removed.  Then it was a simple matter of cutting new larger threads, and now I need to source a new grub screw!   :cheers:



Well, that's about it for now.  Here I am on 12/29, and I accepted several days ago that I will not have enough to demonstrate on 12/31.  However, I really am pretty far along, and I'm hoping I'll get this thing turning very early into 2019.  I'm slow to add to the site, because honestly, what little time I have to myself, I try to get into the garage, or spend it with my family.

Also, if you took very close notice in some of the pictures, it may not surprise you to know that I did start another project.   :embarassed:  I was able to talk my wife into allowing me to purchase an Atlas shaper in need of much love.  As of today, I have it essentially completely broken down, all screws, bolts, pins, gears, etc have been degreased and cleaned.  Most of the paint has been removed from most of the pieces.  I have one very stubborn part (S7-103), and then I can remove paint from the ram too.

After I source a couple of scotch brite wheels for my grinder, I'll commence to really cleaning up the bits and pieces, and possibly even polish certain hardware.  Then, it will be time for paint and assembly.  I am still treating the shaper restoration as a secondary project to the engine though.  If I don't maintain some level of order, it will be total project chaos!   :zap:

Thanks for viewing, and as always, feel free to comment, critique, etc.  I am OBVIOUSLY an amateur, learning more all the time, and I welcome advice and insight.


« Last Edit: December 29, 2018, 03:14:49 PM by vdubjunkie »
“It is difficult to get a man to understand something, when his salary depends on his not understanding it.” - Upton Sinclair

Online 10KPete

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Re: Newbie building a PMR 6CI
« Reply #85 on: December 29, 2018, 03:49:16 PM »
This engine build is going pretty darn well for a 'first' engine! I love your presentation and the fact that you don't hide the bumps and bruises. We all learn by watching and I'd rather watch someone else 'learn' than have to repeat their 'learning'.  :facepalm:

Hang in there and keep on keepin' on!

 :ThumbsUp: :popcorn:

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline Kim

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Re: Newbie building a PMR 6CI
« Reply #86 on: December 29, 2018, 07:45:07 PM »
Wow! That's a lot of progress you crammed into one post!  You're getting close. And learning a ton in the process :)
Thanks for sharing with us,
Kim

Offline b.lindsey

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Re: Newbie building a PMR 6CI
« Reply #87 on: December 29, 2018, 11:02:04 PM »
Great update and things are looking good. Just show what you have on New year's...look pretty impressive to me!

Bill

Offline vdubjunkie

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Re: Newbie building a PMR 6CI
« Reply #88 on: February 01, 2019, 03:13:50 AM »
I need to start this post by reiterating what a superb bunch of people make up this community.  I truly appreciate all of the encouragement, praise, and consideration of any kind.  It is very difficult for me to share all of my mistakes, but you guys make it as easy as possible.

My previous efforts to repair mistaken hole locations in the base were partially successful, but four of the holes needed more efforts.  I decided that a slip fit plug wasn't as likely to do the trick as a threaded one, so I got some 5/8" cast iron rod, and threaded it in the lathe, then cut discs of about 1/4" long each.




My friend was gracious enough to allow me to use his shop again on this particular day, and I was able to do some things I couldn't at home, while others were simply far easier.  Mind you, that huge efficiency gain was thwarted.  It seems one of the employees has acquired a new shop mate.  As I understand it, she is a regular at the shop, and productivity has dropped sharply since her arrival.  I was no exception.




I was also finally able to finish assembly of the crank.  If you recall, I had previously assembled the two crank discs to the crank pin, but the crank rods remained.  Here I am using the shop press to make simple work of this operation.  I had big plans of making this perfect, but I didn't bring certain tooling with me, wasn't finding it in the shop either, and time was slipping away.  So, the keyway in one crank rod might not be absolutely perfectly aligned with the other.   :facepalm:  I'm learning to get over such things.



Later, at home I was able to glean the tiniest bit of interest from my family, so assembled just about as much of the engine as i could while doing some fit tests.  It's getting pretty exciting. 



Here is another view.  Nothing is pretty, well polished, or anything like that.  But, I'm getting the fit of things sorted out, and it's really coming together.



While I was rummaging through tooling at my friend's shop, I found a set of letter and number stamps, and decided to use them to assist with pillow block orientation.  This will prove very useful as I begin to finish everything.



Here is my crank with connecting rod splayed out.  I just wanted a picture of the two together with nothing else.  There's something about the pair that seems to stand alone to me.



While at my friend's shop, I drilled out these holes, but I was trying to allow others to have plenty of time on the machine too, so you can see how I didn't really complete each hole.  Later, I finished each hole with my hand drill.



After completing one hole, I cut in the threads, and ran a "dry fit" of the plug.  It worked out just as I had hoped.  Yes, you may notice that the hole for one of the plugs leaves a fair bit of the wrong hole still exposed.  I struggled with this.  I was trying to not get too close to the edges, and I think I really should have gone closer.  Here will be another opportunity for me to have a possible learning lesson.   :cussing:



Here we are with all of the plugs installed, using loctite.  I can't wait to get these machined down, drilled and tapped corrected holes.



It's taken me a while to get here with the fit of the piston and rings.  I spent a fair bit of time taking measurements from different angles and depths of the cylinder, and around the piston, to ensure the tolerances were where the plans instructed.  Ultimately, I took a chance, and decided I just needed to remove some thickness from the teflon.  This turned out to be correct, the best I can tell.  I think I've finally got a good fit on them.  While I am mechanically inclined, every bit of this is new to me, so it takes me time to feel good about some of these decisions.



Here I've assembled the entire cylinder, valve, and cross head assembly with all four heads installed, to ensure I get travel without binding.  It took just a bit of effort up front to get everything to seat in place as necessary for the movement to be smooth.  At this time, it still requires a fair bit of effort to get the mass into motion.  I'd like to get some compressed air into the intake so I can see how much pressure it takes to push the piston.  It's certainly not 100%, but I'm very close.  When I can finally mount everything to the base, I'll be able to do better tests.

Today I ordered my adjustable reamer so I can finish out the pillow blocks to trap the bronze bushings.  I'm getting so close, it's really starting to get exciting!   :whoohoo:




« Last Edit: February 01, 2019, 03:20:48 AM by vdubjunkie »
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Online 10KPete

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Re: Newbie building a PMR 6CI
« Reply #89 on: February 01, 2019, 04:18:07 AM »
Lookin' good! That half hole on the base? JB Weld. The bottom is on the bottom and the top is covered by the mating part. Degrease and fill 'er up!

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.