Author Topic: PMR #1 Drilling Engine - Mike's 4th Engine  (Read 9781 times)

Offline mikehinz

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PMR #1 Drilling Engine - Mike's 4th Engine
« on: January 21, 2019, 12:57:21 AM »
I think that I mentioned at the end of the build of my 3rd engine that I was contemplating a PM Research #1 Drilling Engine.  Well, I firmed that thought up and made the purchase!  I unpackaged the box and took a look at everything.  My first impression is that the drawings are really excellent and the castings are just a bit on the rough side. 

Here's a pix of the parts roughly arranged in front of my just completed Potty Engineering Horizontal Mill engine.  It's a bit larger and the flywheel is a LOT larger! 


I did make a bit of a start on the engine.  I took the casting for the frame to the belt sander and spent a bit of time flattening the bottom.  Plus a did a bit of filing around the parameter of the frame just to knock off some of the really rough flashing but I did that after this pix.  At the end of the day I got it to sit flat  on my surface plate.  I'll take a better pix later on but I didn't sand it down until it was perfectly smooth, just until it sat flat without rocking. 


That's it for the start!

I might be a bit slow for the next week or so as I had to have a large'ish area cut off my back and it's limiting my ability to lift my left arm above my shoulder at the moment.  So I can do lathe work ok, but the mill is tough.  Might be the justification for a power draw bar!

All for now.

Enjoy!

Mike.
MIke
Wichita, KS, USA

Offline b.lindsey

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #1 on: January 21, 2019, 01:43:51 AM »
Looking forward to this one too Mike. At least this one I have built. I can certainly relate on the rough castings. Yours look a bit better than mine did. Hope the back will mend quickly so you can get back to this build and the Webster.

Bill

Offline Jo

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #2 on: January 21, 2019, 08:51:19 AM »
 Nice set of castings  :)

Five spokes on your flywheel  :thinking: that will be an interesting one to turn the outside rim.

Jo
Enjoyment is more important than achievement.

Online Jasonb

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #3 on: January 21, 2019, 10:00:14 AM »
My first impression is that the drawings are really excellent and the castings are just a bit on the rough side. 

I have noticed that with all the PMR castings that I have seen. Although cleanly cast and well aligned they do seem to use quite a coarse sand which is reflected in the texture of the finished casting.

As Jo says 5 spoke wheels can sometimes be hard to hold inside the rim but you may be lucky as the spokes are quite thin though the size of your chuck and thickness of it's jaws will play a big part in how it can be held. Failing that its an easy fit on a faceplate.

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #4 on: February 13, 2019, 06:00:37 PM »
Nice set of castings  :)

Five spokes on your flywheel  :thinking: that will be an interesting one to turn the outside rim.

Jo

Your comment regarding turning the outside of the rim is indeed prescient!!  I'm about to post as to my progress on the flywheel and what I came up with. 

Thanks!

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #5 on: February 13, 2019, 06:33:03 PM »
After a bit of a gap in posting due to various personal issues, I'm back and I hope to make steady progress on this project as well as the Webster! 

I'll make 2 posts today, first regarding the flywheel and the second regarding other bits of the engine that I've been working on.

First up is some fine flywheel fettling!   I used the belt sander on rim OD to knock down some flashing and to smooth up the seam a bit  and then went over to the vise and removed the flashing from the spokes and from inside the rim.  Shown is the collection of files that I ended up using.


The next thing that I discovered is that Jo was absolutely correct.  My 4J could not grip the inside of the rim due to the spoke placement and the size of the jaws.  Jasonb did give me a clue and that was 'faceplate'.  Shown is the flywheel laid on top of the faceplate that came with my lathe.  The faceplate is 10" diameter and that leads to the next problem.  There's no way to directly hold the flywheel to the faceplate due to the respective sizes!


So what I ended up doing was as follows.  I have a tooling plate that I used on my 6" rotary table.  I took that and drilled 4 more mounting holes that allowed me to mount the tooling plate on the faceplate. 


Also in the pix is shown how I propose to hold the flywheel to the tooling plate.  The holes in the tooling plate are tapped 3/8"-16 which is commonly used for hold downs for 7/16" and 1/2" slotted tables.  I took 4 pieces of 3/8" flat AL stock and cut them to 1" x 3.5" and drilled a thru hole thru the center of each of the bit of the AL packing material.  That way I can catch 4 of the spokes and hopefully secure the flywheel well enough to take some light cuts on the first side and get the hole drilled and reamed thru the center.   It's a little hard to see on the pix, but the AL packing does clear the ID of the rim. 

So does everyone think that this approach will work OK?  Is this method secure enough to hold the flywheel for some light operations?  All input is certainly welcome!

I'll have another post in a bit.

Enjoy!

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #6 on: February 13, 2019, 09:26:07 PM »
This post is regarding various parts in various stages of progress.  My high-level plan is to do the base of the engine first as many other parts need to be fitted to it during the construction.  Of course I soon realized that I need various other parts to check if the base is correct in the first place.  In any case, here's the tale.

I spend some time on this collection of parts with the belt grinder and files.  My goal was just to remove most of the flashing so as to allow easier holding on lathe and mill.  Also most of these parts will need to be fitted to the base fairly early in the build.


Based on Bill L's posts regarding this engine, there's a possible issue when establishing the height of the crosshead slides vs the centerline of the cylinder vs the top of the frame matching the top of the cylinder.  So I spent a bit of time with the height gage looking at the frame and figuring out how much I could mill away on the frame crossline bottom guides.  I'll spare everyone the math but I believe I need to mill away about .055" from the top of the crosshead slide guides so as to make the centerline of the cylinder end up in the correct spot.  My assumption was that the top of the frame (where the cylinder is bolted up) won't have any material removed (other than a bit of filing for smoothing) and hence will be used to establish the centerline.  Note my old Starrett 254 Master height gage.  Its a great old instrument but the older I get, the harder it gets to read accurately even thought its about as easy to read as any vernier instrument.  One of these days I'll probably trade it for a digital just to be able read it!


Then on to milling the bearing caps flat.   More work to do down the road but this gets them started.  That's the old CentreDex insert end mill.  Still works good on CI!


Both of the caps laying on the print.  Both are flat and are to width.  I still have to put the 'step' in each of them. 


After a bit of contemplation and reading other threads on this build, I came to the conclusion that I needed a tooling plate to hold the base of the engine for the various options that needed to be done.  This pix shows a piece of .75" AL that cut to size and flycut smooth on both sides.  I'm just contemplating if this will work and where the hold-downs should be placed.


This pix will make more sense in a bit, but here I have the engine base bolted to the tooling plate in a couple of places and I'm making sure that the engine base is as close aligned with the X axis as I can make it, given that it's a rough casting. 


After I got it aligned as best I could, I used a 1/4" extended length end mill to make the 6 areas where the base bolts will go as flat as possible.


Shown after I had all the bolt-down areas milled flat.


Drilling thru each flat area with a 1/8" drill as per the drawing.  It was a bit challenging to get the hole in the center as it has to be done pretty much by eye and I'm not that great at that job, but the holes ended up close enough, I think.  I may use a small brass washer under each bolt just hide my sins!


After the thru holes were drilled in the base, I removed it and then drilled and tapped 4-40 at 6 places based on the dimple from the thru drilling operation.  You can see the 3/8-16 drilled and tapped holes for the hold down hardware.  Plus I lightly scribed lines around the engine base so that i could get it back into place as closely as possible.


And here's the engine base screwed down to the tooling plate in the final position that I chose.  I plan to leave it screwed down as shown plus add up to 3 additional hold downs depending on the operation I'm doing and the need for clearance.  Hopefully this will be rigid enough for all the operations needed.


I decided to try to use the casting for the crankshaft vs a built-up crankshaft, mostly since I want to see if i can do it this way.
First, i wanted to get center holes into each end of the crankshaft casting.  As you can see the crankshaft will go entirely thru the center of my 4J so I shoved it thru.


Then I tightened the 4J on the crankshaft and centered it up as closely as possible as shown.


Then faced the end off flat.


Then center drilled each end.


That pretty much catches me up with progress pix.  I'll keep working on the base and crankshaft assembly as well as the parts that need to be fitted to the base.

All for now.

Enjoy!

Mike
MIke
Wichita, KS, USA

Offline b.lindsey

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #7 on: February 13, 2019, 10:04:21 PM »
 You are making some good progress Mike. Good to see an update on this one.

Bill

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #8 on: February 13, 2019, 11:17:02 PM »
This reply originally was about the failure of the spindle adapter on the collet closer on my lathe.  Rather than posting only indirectly related info in this build thread, I've started a new topic in  'Supporting / Tools & Machine'.  I'll post anything relating to the failure, part design, and hopefully eventual repair in that thread. 

For convenience, the lathe repair thread is linked below.

http://www.modelenginemaker.com/index.php?topic=8867.new#new

FYI.

Mike

« Last Edit: February 15, 2019, 12:09:19 AM by mikehinz »
MIke
Wichita, KS, USA

Offline MJM460

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #9 on: February 14, 2019, 02:51:17 AM »
I share your sorrow, Mile, I use my collets a lot too.  (But just a manual drawbar closer.)

Hard to believe a manufacturer turned that bore with so little clearance, I wonder if the previous owner wanted to use a larger bar and had to skim it out.

Will be interested in how you go in the thread cutting for the replacement.  Please keep posting.  Keeping the lathe in operation is surely relevant to the build.

While on the topic, I often wonder just how much solid metal you have to leave between a thread and a hole through the centre.  Clearly the root diameter is less than the tapping drill size, can be calculated, but what about any micro cracking from the threading process?  And it has to be strong enough to take the torque from the thread cutting or hole boring process.  One of those design decisions that always leaves me scratching my head.

MJM460

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Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #10 on: February 15, 2019, 12:11:15 AM »
I share your sorrow, Mile, I use my collets a lot too.  (But just a manual drawbar closer.)

Hard to believe a manufacturer turned that bore with so little clearance, I wonder if the previous owner wanted to use a larger bar and had to skim it out.

Will be interested in how you go in the thread cutting for the replacement.  Please keep posting.  Keeping the lathe in operation is surely relevant to the build.

While on the topic, I often wonder just how much solid metal you have to leave between a thread and a hole through the centre.  Clearly the root diameter is less than the tapping drill size, can be calculated, but what about any micro cracking from the threading process?  And it has to be strong enough to take the torque from the thread cutting or hole boring process.  One of those design decisions that always leaves me scratching my head.

MJM460

MJM, see the above post.  I'm moving discussions of the lathe spindle adapter repair to a more relevant section of the forum.

http://www.modelenginemaker.com/index.php/topic,8867.0.html

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #11 on: February 15, 2019, 12:36:03 AM »
I got back onto the flywheel work today.  See the following series of pix and at the end, a question for the group.

Here's the face plate, tooling plate attached and the flywheel all mounted on the lathe.  I'm checking and adjusting the runout of the inside of the rim between the spokes mostly by eye with the surface gage pointer as a reference.  The packing is 4 pieces of 3/8" thick AL with a thru hole in the middle of each piece.  My thinking is/was that this arrangement should be sufficient for light cuts plus if something were to loosen up, the packing would be captured and wouldn't go flying.


Starting to take cuts on the rim.  I was only taking cuts of about .010" on diameter per pass.  I didn't notice any hard spots and the OD wasn't that bad.  I ended up taking about .090" off the diameter to get the rim OD smooth.  I did get a bit of chatter but managed to minimize by slowing the lathe way down to 90 rpm and taking light cuts of .005 to .010. 


I took a couple of passes and faced off the hub and turned the OD of the hub at the same time.  I used a 3mm carbide insert tool and it cut fine at about 450 rpm. 


Spot drilled and then drilled thru 1/64" under 3/8"  430 rpm.  The drilling operation went very well.


Reamed to 3/8" and checked the fit with a piece of 3/8" drill rod.  It's a very snug fit so I think I'll be able to make a mandrel that will work well.


Take a look at the following 2 pix.  I took .105" off this side and still didn't get all the rough spots out.  This is one of the remaining rough spots.


This is the other rough spot.  You can also see some of the chatter marks but I think I'll be able to get that out when I have it spun up on the mandrel.  Some emery and Scotch Brite should do the trick. 


And the final pix or today of the first completed side of the flywheel on top of the print.


So here's my question.  The flywheel casting was only about .57" thick to start with.  I had to take .105" off the first side so now I'm down to .47" width on the flywheel.  I assume the 2nd side will be about the same which would take me down to only about 3/8" width for the finished flywheel. 

Is this acceptable?  I thought that the finished wish would be about .50" or so.  I was thinking about maybe getting a cast flywheel from Martin Model and Pattern as my last experience with their flywheels was really good.  Plenty of meat and easy to turn.  Or is having a 3/8" width flywheel ok for this engine?  The flywheel is certainly a spindly looking thing but even the photos on the PMR website show it to be quite think looking.  So, should i live with it or look at replacing it?

Thanks for taking a look and thanks in advance for any advise!

Mike
MIke
Wichita, KS, USA

Offline b.lindsey

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #12 on: February 15, 2019, 12:52:23 AM »
 Mike, as long as it cleans up on the second side to your satisfaction I would keep going with it. If I can remember to, I will measure my final width tomorrow and let you know.

Bill
« Last Edit: February 15, 2019, 08:49:32 PM by b.lindsey »

Offline b.lindsey

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #13 on: February 15, 2019, 08:53:38 PM »
Mike, I did measure the width of my flywheel today and it ended up at .506".  You still may be ok at .375", but that is getting on the thin side. Given the large diameter, you may still have enough mass in the rim

Bill

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #14 on: February 15, 2019, 08:57:59 PM »
Mike, I did measure the width of my flywheel today and it ended up at .506".  You still may be ok at .375", but that is getting on the thin side. Given the large diameter, you may still have enough mass in the rim

Bill

Bill.

Thanks for that measurement.  I assume that there were just very deep inclusions on that side of the rim.  When I machine the opposite side I'll see how much I have to take off on that side.  I may put up with it being a big asymmetric in width just to try to preserve the mass.  I doubt anyone would notice that since one side is mounted next to the engine and not everyone will look at the fine details like such as the rim symmetry, although I'm sure it will bother me!

Would PMR send a new flywheel if asked, I wonder? 

Thanks.

MIke
MIke
Wichita, KS, USA

Offline b.lindsey

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #15 on: February 15, 2019, 09:44:46 PM »
 Mike, it wouldn't hurt to call and ask them. I suspect they will given how much you had to take off due to the inclusions/voids.

Bilk

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #16 on: February 20, 2019, 01:38:17 AM »
Just a quick update on the flywheel.  Since I had to install my 4J today for the work I was doing on my spindle adapter repair, I went ahead and chucked up the flywheel leaving enough of the rim exposed to indicated it in.  I also used a small steel block as a spacer to firmly seat the other side of the flywheel that had been previously trued up, against the inside face of the 4J chuck jaws. 

After doing so I took a cut on the exposed side of the rim and on the outer face of the hub.  Surprisingly and very much unlike the other side of the flywheel I only had to take off about .030 in order to clean it up. 


The last pix shows the just completed side against the print.  It looks a bit like it's not cleaned up but that's just some oil in a couple of places.


The flywheel rim width ended up being .43".  The rim is a bit off center since I had to take so much from the first side.  However, I think I'll leave it as it as if it gets to bothering me too much, I'll order a new flywheel casting from PMR or perhaps Martin Pattern and Model. 

Nexts I plan to make a simple mandrel out of some 3/8" drill rod and Loctite it in place.  Then I'll take some very light cuts to make the rim and sides of the rim run true to the hub.  Hopefully that will work OK without too much ringing and chatter! 

All for now.

Enjoy!

Mike.
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #17 on: February 24, 2021, 08:06:03 PM »
Well, after a very long absence from any work in my shop or posting on this forum, due to various issues in life, I've made it back!  Over the last few weeks, I've made a fair bit of progress on the PMR #1 kit and I'll catch up on my progress over the next few days and hopefully soon get caught up to present day. 

It's good to be back working in the shop again!
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #18 on: February 24, 2021, 08:12:19 PM »
Just to show finishing up the flywheel:

I used Loctite 638 and glued in a piece of drill rod and then mounted the same in a collet block and inclined it in my mill vise just to get the clearance required to make the drill and tap for the set screw. 

First milled a flat:


Then tapped the hole :


So the flywheel is now completely finished.

Mike

MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #19 on: February 24, 2021, 08:44:35 PM »
Next is getting some fairly major work done on the frame.

Since it had been quite some time since I'd made the fixture for the frame, I mounted it in the mill vise and indicated a ground rod laid in the slides just to make sure that it was reasonably square with the world.



Milling the top of the slide surfaces to the required dimension from the top of the cylinder mounting flange as per the prints.



Milling the area between the bearing bosses as per the print.  I had to use an extended end mill to reach the areas.  i never like using those extended end mills as the tend to chatter with the slightest bit of pressure.



After milling the area between the slide surfaces to the dims called out in the print, I used a Starrett adjustable parallel to confirm the dimension.



Milling a groove on the rough bearing surfaces to be used to determine the centerline of the TBD bearing surfaces.  I measured the height off the slide surfaces and added/subtracted as necessary to get to the centerline of what will be the cylinder.



I took the groove 'forward' and 'down' to assure that a 3/16" pin's center would be exactly where the center of the bearings would need to end up.



Drilling and tapping the required 5-40 holes for mounting the spaces for the top slides.  Locations were determined from the centerline of the frame and per the print, assuring that the holes were equally distanced from the end of the slide surfaces.



Bolted the fixture plate on my 90 degree angle plate and make sure the frame was level horizontally.



And vertically as measured from the slide surfaces:



Found center in y from the edge of the fixture plate as I'd previously determined that the frame was within .001" on center of the fixture:



Then to position in x, I clamped a 123 block on the slide surfaces, found the edge and then figured out where I need 0 from there.



Used my boring head to create the round mounting area for the cylinder.  I'd just started cutting in this pix.   The flat area was from a previous operation.  I put that feature there with an end mill so i had a reference for the operations when the frame was mounted horizontally. 



After drilling pilot hole in the center, i used some feeler gauges to make sure that the slide surfaces and centerline of the cylinder ended up at the proper locations.



Drilled the center hole plus the bolt pattern for mounting the cylinder plus drilled and tapped the 2-56 holes for the backing gland.  I just use the DRO on the mill, but since my DRO is an old Sony with limited features, I lay out what I need in CAD and then just use the x,y coordinates generated to move the mill table as needed.  This works well for me.



The frame almost done, except for the bearing surface that need to be at 45 degrees plus of course getting the required 3/8" thru the bearing area for the crankshaft.



This should do it for this post.

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #20 on: February 24, 2021, 08:55:21 PM »
A few pix of finishing the bearing caps.   I'd previously flattened the bottoms and cleaned them up a bit on my belt sander.

Drilling the thru holes for the bolts.  Caps are mounted on each end of the mill vise to make sure they're well gripped on the vise.  I'd zero'd the DRO on the left rear of the mill vise so I just swapped the caps whenever I finished one.



I set the caps at 45 degrees with an angle block and spot face and drilling and tapped for the oil cup locations.



Top side of the caps finished.



Turned the caps over and made sure that they were flat.  I'd put them on top of parallels but since they were rough on that side, i wanted to be sure.



Milling the bottom feature on the caps.  This locates the bearing caps at the correct position on the frame. 



And finally the caps completed as shown from the bottom surface.  The hole is the oil cup mounting hole that I drilled thru. 



And that's it for the posting for today.  More tomorrow hopefully.

Mike
MIke
Wichita, KS, USA

Offline propforward

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #21 on: February 25, 2021, 01:09:14 AM »
Well, after a very long absence from any work in my shop or posting on this forum, due to various issues in life, I've made it back!  Over the last few weeks, I've made a fair bit of progress on the PMR #1 kit and I'll catch up on my progress over the next few days and hopefully soon get caught up to present day. 

It's good to be back working in the shop again!

Glad to see you back. Your work on the engine is top shelf - very nice indeed.
Stuart

Forging ahead regardless.

Offline cnr6400

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #22 on: February 25, 2021, 02:39:02 AM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
"I've cut that stock three times, and it's still too short!"

Offline bent

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #23 on: February 25, 2021, 05:52:51 PM »
Looking good!  No apologies for delays required, it's been quite the year+ for me too.  Hope to get back to hobby machining soon,  maybe once the weather warms a bit.

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #24 on: February 25, 2021, 06:40:28 PM »
This series of pix shows how I machined the bearing cap surfaces on the frame. 

First was to get the frame, which is mounted on the fixture plate to a 45 degree angle.  I do have an adjustable angle plate, but pure laziness and sloth made me just clamp the fixture place in my Kurt vise.  The angle block is just shown for reference.  I actually turned it over and used a DTI to make sure the angle was correct.



Then i swept the 3/16" pin with the DTI to make sure the frame was actually square with the mill.  I didn't show it, but I knew that the center of the 3/16" pin is exactly on the bearing hole centerline.  So I touched off of the top of the pin and then did the arithmetic to get the bearing surfaces and the notch to the correct depths. 



After milling the features on the top, measuring the .500" slot with using an adjustable parallel.  I did manage to actually hit the dimension on the nose!  Miracles do occur!



Drilling the hole pattern on both sides for the bearing caps.



Then threading the holes 3-48 using a spring loaded tap follower and a very small tap handle.   I do like working with cast iron as it machines and taps easily.



The bearing caps fitted.  Everything went together well. The bearing caps are even with the frame on the inside, but not on the outside, but I think that this is what's intended on the prints.



So that does it for getting the bearing caps onto the frame.  Everything came out good so far!

Mike

MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #25 on: February 25, 2021, 07:28:20 PM »
On to making the hole thru the frame and bearing caps for the crankshaft.  I was somewhat afraid of this operation as the surfaces are a bit uneven and there's the existing groove for locating the c/l.  In any case, here we go!

There's actually a lot going on this pix.  I bolted the fixture plate onto the 90 degree angle plate and spaced it up with some 123 block.  The 3/16" pin is held into the previously milled groove with some longer 3-48 screws to make sure it stays in place.  Then I swept the pin vertically in both axis to make sure the frame is straight and luckily it was as I was pretty careful when i made the fixture plate.  Lastly I centered the spindle over the pin and locked the mill table down once I was on center.



Then I milled a flat area with a 3/8" end mill just to make sure that I had a flat surface to start on.  I didn't show the pix, but I think used a 5/16 EM to make the initial hole thru the top most area on the frame and then used an extended 1/4" EM to mill thru the bottom area of the frame. 



Since I now had a (hopefully) straight hole thru both sides of the frame and bearing cap area, I then drill thru 1ith a 23/64" bit.  And since the previously made holes with the end mills were straight, the bit should also remain straight thru both existing holes.



Then finished the hole feature by reaming thru with a .375 reamer.  The crankshaft is spec'd to be .374" so there should be clearance, plus when the crank is made it can be tested against the frame to be sure.



And finally checking the fit with a piece of on-size drill rod.  The drill rod fit well when the caps were tightened down and the rod could be rotated by hand, so I declared success on this operation!  This turned out to be a relief to me as I had feared that something might go horribly wrong somewhere during this process.



All for now.  I'll post more tomorrow or the next day as I progressed on the other parts of the engine.

Enjoy!

MIke.



MIke
Wichita, KS, USA

Offline samc88

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #26 on: February 25, 2021, 09:47:52 PM »
Nice work so far Mike

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #27 on: February 26, 2021, 03:28:47 PM »
Now we're back to some of the smaller parts that need to be checked for fitment against the frame once done.

First is the crosshead.  The raw casting was pretty good, that is more or less straight and square and had plenty of material that could be removed so it was relatively easy to get to the final part.  I measured the width and estimated how much need to come off each side.  The raw part could be gripped security just by placing it in the vice as shown.



Then I turned the part 90 degrees and finished the top of the slide area.  First one side:



Then the other side.  Confirmed the thickness dimension as that's fairly important as it has to slide between guide surface on the frame and the top slide. 



Further workholding on the part becomes tricky from this point on, so I made a couple of AL bits that allowed the part to be held in the vise as required by the just milled flat surfaces.  Alternatively, if you didn't care about maintaining the original appearance of the part, the enter area could have been milled flat and held securely after that operation.  I wanted to try to maintain the original appearance.



Part being held by the little fixtures resting on parallels.  This was milling the side of the circular area flat and to dimension.



Then bluing the part, finding the center of it, pretty much by eye and starting the spot drilling/drilling/reaming ops to get to .25"



.25" pin shown thru the part to verify the hole was correct.



Squaring the part up in preparation for bringing it to length.



Milling the part to length and sacrificing a bit of the fixtures in the process.  I didn't get a pix of what I had done previously, but I'd marked the length from the center of the hole as per the print, and simply milled to down to that mark.



Next I needed to mill the slot for the connecting rod into the part.  I had to think about this a bit as the measurement for the slot is taken from the centerline of the hole, but there was no way to get that measurement without a pin in place.  So what ended up doing was to pin a .25" pin in the hole, set the vise stop rod, find the edge of the pin, then remove the part, remove the pin from it and place the part back in the vise against the stop rod. 



Milling the slot.  I used an under-width end mill and then moved off the centerline equally in the y axis to bring it to the final width.  Surface finish was good in the slot.



Gauging the slot width with a pin. 



And the finished part on top of the print.  I actually did drill and tap the 10-32 hole in the end of the part, but failed to take a pix of that op.  But nothing tricky about it as it was easy to find the location and this material, although a bit sticky, drill and taps easily.



So, this part is finished and I confirmed it fit within the frame slide area. 

All for now.  Enjoy!

Mike



MIke
Wichita, KS, USA

Offline bent

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #28 on: February 26, 2021, 03:48:54 PM »
I think it adds a lot to the look of an engine to keep as much of the "as cast" surface as possible.  Good job, in my book.

Offline Johnmcc69

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #29 on: February 26, 2021, 03:49:31 PM »
 :ThumbsUp:
 Great set up's & fixturing Mike!

 John

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #30 on: February 26, 2021, 07:22:55 PM »
I think it adds a lot to the look of an engine to keep as much of the "as cast" surface as possible.  Good job, in my book.

Thanks!  I agree with trying to keep as much as the 'as cast' look as possible.  I'm trying to go for the most realistic look possible on this engine.

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #31 on: February 26, 2021, 07:24:18 PM »
:ThumbsUp:
 Great set up's & fixturing Mike!

 John

Thanks!  It turns out i've been spending a LOT more time thinking about how to hold the parts and creating the fixtures necessary vs cutting metal directly.  I'm sure that's a common finding for most!

Mike
MIke
Wichita, KS, USA

Offline crueby

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #32 on: February 26, 2021, 07:26:30 PM »
:ThumbsUp:
 Great set up's & fixturing Mike!

 John

Thanks!  It turns out i've been spending a LOT more time thinking about how to hold the parts and creating the fixtures necessary vs cutting metal directly.  I'm sure that's a common finding for most!

Mike
Yup! Very important thing to work out ahead of cutting.     :popcorn: :popcorn: :popcorn:

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #33 on: February 27, 2021, 01:32:35 PM »
Now on to a few smaller parts.

First up is the slide caps.  These were actually quite good as received.  I just touched the bottom to the belt sander very briefly to knock the worst roughness down a bit and did the same to the sides just to remove the bit of flashing left on.  Then just a few strokes against some 400 grint sandpaper laid on top of a flat.  I also spent some time with a file on the round end to clean them up the best I could while still keeping the draft angle intact.  I didn't show any pix of those ops, but here's a a few pix with the caps clamped in the mill vise.  I've already drilled thru the ends as per the print and about to drill thru the center oil hole with a #60 bit. 



Then tapping the top of the hole 2-56 with a spring loaded tap follower and a very small tap handle. 



And the last pix of the caps on the print as finished.  Note that I drilled thru with a #60 bit as I didn't have a 1/32" bit on hand and felt like it wasn't worth making a run to my local supplier just for that small bit.



Next is the .25" brass spacers for spacing the slide caps from the frame.  This was pretty simple as a small piece of brass rod was supplied that just needed to be squared up and drilled thru.  Shown is parting off one of the spacers to length.



Then I made the valve rod and the piston rod.  Shown is the valve rod laid on top of my home-made tailstock die holder.  This device works very well.  It can hold 13/16" and 1" diameter dies and that's more than enough for 99% of the work I do.  Bigger than that, I use a standard die stock.   In any case, here it is:



The piston rod finished and laying on top of the print:



And finally the finished parts shown assembled onto the frame and the slide movement checked.  I did end up filing down the cross slide width just a bit to make sure it slid absolutely freely along its entire travel.



And one last piece for today, the cross nut.  Again, not a terribly complex part.  I didn't take a pix of the op, but I drilled the required hole thru the supplied stock on the mill and tapped it 5-40 as per the print.  Then I installed the stock in the lathe using a square collet  and parted it off to the specified length.



And the last pix shows the cross nut assembled on to the valve rod both parts laid on top of the print.



So far so good.  That's it for today.  I'm off to the top to try to solve the mysteries of model pipe threads and threading.  I have taps and dies and need to figure out what works somehow.  Questions maybe forthcoming!

Enjoy!

Mike
MIke
Wichita, KS, USA

Offline propforward

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #34 on: February 27, 2021, 01:51:59 PM »
I am mightily impressed. You are making a really top job of this, far beyond my own bungling and lame attempts on this same engine. Hats off to you.
Stuart

Forging ahead regardless.

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #35 on: February 28, 2021, 02:44:18 PM »
And now on to some really small fiddly bits, the linkage hinge pieces!

I used a square collet in the lathe, drilled and tapped a hole in each end of 2 piece, beveled it slightly and cut the 2 bits to length.  I didn't take any pix but here's the results so far.



Then off to the mill vise.  I used a 3/32" carbide end mill to mill away the center or edges of the bit respectively.



I had to change orientation of one of the bits at some point in order to get the milling done.



A pix showing how small these bits really are.  I rounded the corners off with a belt sander, very carefully comparing with a radius gauge and checking the fit periodically.  That op is not shown. 



The valve rod assembly so far.  Everything fits luckily!



No pix of the operations, but here's the final pix of all the brass nuts that needed to be made.  Sizes are 5-40 and 10-32.  This just involved using a hex collet on the lathe, drilling thru and tapping, beveling the edge, parting off and then turning each nut around in the collet and finishing and beveling the backside of each piece.  The only tricky part is getting the parted off nut held in the collet.  I just threaded each nut onto a screw, then inserted it into the collet and made sure it was running straight and performed the bevel and polishing bit.



And lastly the eccentric rod.  I just cut the rod to the required length, marked the bend locations and by hand, bent the rod while held in my bench vise.  I compared it against the print during the process to make sure the bends were about correct.  I think there's some tolerance in all this so close is good enough!



All for today.  Enjoy!

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #36 on: March 03, 2021, 03:01:15 PM »
And we're on to the cylinder in today's pix.  This part has some challenges due to the references required and when they become possible to measure from.  So, some of the steps and setups have to be repeated in order to get to various final dimensions, at least the way i thought about it and did it. 

First pix is the raw casting, just after I worked it over a bit on the belt sander.  This was to just take off the worse of the rough spots and get flat enough surfaces to be secured in the vise.  Notice in the print, the first tricky dimension.  Note that 2 dims are referenced from the center of the valve rod hole, that is the top of the valve chest and the bottom of the slide valve surface.  But that feature can't be done initially since the part is very difficult to hold at this point.   Also note that i used a permanent marker to note the front and rear of the cylinder as the raw casting is symmetrical but the operations make it non-symmetrical as the valve rod boss is removed from the top but left on the bottom.  This matters as the inlet port needs to end up on top and the outlet port needs to be on the bottom when finished. 



So the first thing I did was to hold the cylinder by the ends using some AL packing against the moveable vise jaw.  Then I used a 1/4" carbide end mill to just lean up the face of the valve chest and the bottom of the valve chest.  There was no attempt to get to the stated dims at this point, I just wanted to get some flat surfaces. 



Now since the valve chest face is flat, I oriented that face toward the fixed jaw and used some packing against the moveable jaw.  Then I squared it up as much as possible using a machinists square on the side and indicating across the top keeping in mind that the casting is still quite rough.



One end of the cylinder finished.  This isn't done to an exact dimension, but rather I milled it down until the surface was smooth and the valve rod boss more or less disappeared.  At least is LOOKS like the print at this point, but its not yet possible to hit an exact dimension here.



Now we have 2 flat surfaces!!  So, now the cylinder is flipped over and can sit flat on a parallel on the bottom and flat against the fixed jaw.  AL packing is still used on the moveable jaw side.  So milling can commence!  And of course now it's possible to get the cylinder OAL to spec.   That's a 1/4" carbide EM spun "pretty fast"!



Measuring the length of the cylinder using a depth gauge to get the OAL to the print spec. 



Part shown against the print just for reference:



Next is finishing up the valve rod packing gland area.  This involved drilling thru then creating a recess for the packing material and drilling and tapping 2-56 for the small fasteners used to hold the packing gland in place.  This is my typical setup for tapping small holes, a spring loaded tap follower and a very small tap wrench.



Now back to finish off the valve chest area since we have the required reference feature.  First I oriented the cylinder in the mill vise now having 3 flat surfaces!  I used a DTI get the cylinder oriented as flat as possible.



Then I used a depth mic measuring to a 1/8" rod inserted thru the valve rod hole.  That way I could figure out the required distance from the center of the rod hole to the top of the valve chest and from that feature to the bottom.



Then taking the top of the valve chest to the required dim using a 1/2" EM.



Taking the bottom of the valve chest to .438" from the top, but of course this is really referenced from the center of the valve rod hole.  I used a 1/4" carbide EM for this operation.  Also I had set the centerline using the 1/8" rod thru the valve rod hole, as this really need to be the center of the part from this point forward.



Next was milling the rather deep exhaust and intake ports into the bottom of the valve chest.  This is the start of the exhaust port using a 3/16" EM.  The tricky thing is that it's hard to see what's going on down deep in the valve chest plus I frequently used a vacuum and/or air blast to clear the chips quite often.



Then doing the inlet port using a 3/32" carbide EM.  Note that I wrote the movement of X on the vise as I really, really didn't want to screw things up at this point!



Last operation at this orientation of the part was to drill and tap the holes for the cover plate.  Pretty straightforward, just moves using the DRO in x,y.  Centerline was still established from the previous operation. 



The cylinder against the print trying to show the operations completed so far.



Next comes the cylinder boring operation.  The tricky part is to figure out where the cylinder center should be, as the rough cored hole isn't at center nor is it round or smooth.  So what I did was to indicate the valve rod packing area hole to make sure the spindle was exactly on the Y axis centerline as I'm taking that feature as the center of the cylinder's world.  X should also be fixed at this point. 




Then I used a DTI ball point just for a reference, and swept the OD of the cylinder to get cylinder as close as possible in Y. 



Then I moved the DTI ball point to close to the existing cast center hole and swept that area to see how close to center is actually is/was.  It turned out to be not good, but not terrible either and it's oblong with a one very rough side.  But there's plenty of material so it should clean up just fine. 



Then I started to bore using my Criterion boring head and as short a bar as I could use to get thru the entire depth.  You can see that start of the cut cleans up the bore pretty well, the difference between sides turned out to be about .020"



Then boring and measuring until the 1.000" target is achieved.



I also gauged the hole with a 1" plug that I had on hand from a previous project.



Next was drilling and tapping the cylinder cover holes 5-40.  I did this with x,y moves on the DRO after centering up the cylinder.  I drew up the pattern with the required PD and hole placement using CAD as I don't have a hole pattern function on my rather old DRO.  Same operation on each end of the cylinder.



The cylinder shown against the print.  More ops still to come!



I lapped the cylinder to get it as round as smooth as possible.  I used Timesavers abrasive material and a 1" brass lap progressing from course to medium to fine. 



I turned the lap as slow as possible in my lathe while hand holding the cylinder.  It always amazes me how much difference lapping makes.  You THINK you have a smooth, round hole, but lapping improves it greatly.  I went thru this process as I intend to use an o'ring for the piston seal.



Next comes the scariest part, at least to me!  One of my fears, is that by this point in the process, I've put some much time into the part that screwing it up during the final ops would be very painful!!  This is drilling the inlet and exhaust ports between the cylinder and the valve chest.  The print calls for these holes to be drilled at 20 degrees so a bit of a tricky setup is needed.  I don't have any sort of any compound sine vise but I do have a Kurt vise mounted on my mill and I have a small toolmaker's vise.  So the first thing was to get the toolmaker's vise mounted in the Kurt at 20 degrees.  I used a 20 degree angle block, inverted it in the toolmaker's vise and indicated it flat.



Then after setting up the toolmaker's vise at the correct angle, I used a tooling ball inserted in an adapter that fit the cylinder.



Then indicating the ball in order to find the 'center' of the cylinder, which of course is really the center in Y but in X is center as included, but not when flat.  Soooo, recalling high school level geometry and trigonometry, it is possible to find the required dimension of the print, which is specified when the part is flat. 



I didn't show how the operations started, but once I found the required dimensions, I used a 1/8" end mill to create a flat spot at each location in order to start the drilling operation.  This is necessary so that the drill starts straight.  The drilling operation is shown.  The drill need to end up in each of the inlet ports.  The same operations need to performed on each end of the cylinder, but I don't show the operations on the other end.



Just to prove that the holes are correct, I shined a light from each end and it can be seen in the ports within the valve chest.

First end:



Second end:



I didn't the operation but the prints call for the inlet ports to be enlarged fully to 1/8" width and 1/8" deep.  I didn't show the operation, but this just involves placing the cylinder in the vise in the flat position, find center, establishing the cutter depth and making the cuts.  Shown is the finished cylinder end, same on both ends.



At last, we're at the very last operations on the cylinder!!  This is drilling/tapping the inlet and exhaust ports.  The prints call for 1/4-40 and I'd never run into this particular thread before.  Some searching revealed many standards for model pressure piping and I became ever more confused the more I read.  It turns out that I very possible got some bad taps from a vendor (I'll document more issues separately in the appropriate forum) but I DID end up with taps that worked that are the METP (Model Engineering Taper Pipe) also known as MTP (Model Taper Pipe) in 1/4-40 size.  These are of course taper type taps so tapping depth is critical.  So after I sorted this all out, here are the pix.

I placed the cylinder as required in the mill vise and then inserted a 1" rod thru the cylinder and indicated it to make sure the bore of the cylinder was horizontal.  I did this to assure that the to be drilled ports landed in the correct locations.



Since there's no real reference to these port locations, other than 'center of boss', I inserted a 1/2" rod in the mill spindle and visually centered the rod over the port boss. 



Then I skimmed the boss with an 1/2" EM taking about .005" off just so as to clean up the surface.



Then drilling thru with a #5 drill.



Then tapping with the 1/4-40 METP tap.  I checked the depth frequently to assure the taper was not too deep nor too shallow.



Each port completed and shown with some brass fitting from PM Research.  Going forward I'll probably make my pipe fittings as I did also purchase the require dies.



Using a light to make sure the exhaust port is drilled properly.



And finally, smoothing the valve chest bottom face using some fine emery cloth and using the slide valve for pressure.



Whew!  I got thru the entire part with no major mistakes!  This took several days as I spent a LOT of time thinking about the order of operations and how to do certain things.  Choosing the inlet/outlet threading method also took some time as there seem to be sooo many standards and approaches plus getting some bad taps initially also slowed me know.

In any case, took a look and enjoy!

Mike






MIke
Wichita, KS, USA

Offline tvoght

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #37 on: March 03, 2021, 03:38:49 PM »
Mike, I enjoy your setups and logical approach. The photos are good and descriptive.   --Tim

Offline Johnmcc69

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #38 on: March 04, 2021, 12:34:14 AM »
 :ThumbsUp:
 Great work on the cylinder!
  :popcorn:
 John

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #39 on: March 04, 2021, 04:14:18 PM »
John, Tim, thanks for taking a look and thanks for your complements!

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #40 on: March 04, 2021, 04:33:05 PM »
Now that I have the cylinder finished, I wanted to make the associated parts so that I can check fitment of each as I go along. 

So first up is the valve chest cover.  The raw casting was pretty smooth and flat, so I just worked the topside against some sandpaper to reveal the screw boss locations.  Then I put it on some parallels in the mill vise and very lightly skimmed the bottom side with my almost antique Valenite insert end mill.  I only took off about .010" and it cleaned up pretty well.



Bottom view as finished.



Top view showing the screw bosses after just a few strokes against sandpaper on a surface plate.  I didn't mill the boss locations at all.



Tested the fitment against the cover on the valve chest.  I wanted to see how it looked with brass washers under the bolts, but that doesn't look right to me, so I'll end up with just plain scale bolts when it's finally assenmbled.



Next on to the slide valve.

First is just cleaning up the bottom with a 3/8" EM.  I took a minimal amount off, something like .015"



Then I inverted the slide valve and milled the required slots as per the print using an 1/8" HSS EM.  I didn't show it, but I did test the fit of the valve rod and the valve nut against the slots, both separately and when assembled.  I went for a bit of a loose fit slide nut to slot fitment.



I didn't show the operations, but here's the slide valve inserted showing the milled recess as per the prints.  Fairly straightforward using a 1/8" carbide EM.  The trick being carefully watching the DRO so as NOT to overshoot any of the moves.  General laziness prevented me from doing the obvious and setting stops!



And finally for this part, the slide valve assembly shown in the cylinder valve chest in order to test the fitment.  All good!



This is probably enough for this post.  I'll post another short series of pix showing the top and bottom cylinder heads here shortly.

All for now.   Enjoy!

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #41 on: March 04, 2021, 05:03:44 PM »
I wanted to post on how I did the cylinder heads yet today. 

First up is the bottom cylinder head, the one that's cast bronze.  To start the part, i used my 3 jaw chuck and gripped it as well as possible on the extra-long spigot and then turned the larger OD, but I left it a bit oversize at this point.  The pix shows the ops after I turned the part around and started turning the spigot down to its final OD. 



Then I installed the collet setup on my lathe, and gripped the head by the spigot.  Then I turned the OD to the final dimension.  Doing so now makes sure that the OD of the part is concentric with the spigot and the TBD drilled thru hole.  I also thinned the part as required and make the .031" boss as called out on the prints. 

Shown is the cylinder head against the print, partially completed.



To finish the part, I used a 'pot' 5C collet.  Shown is milling out a recess in the collet so that I could grip the part.  Use of this type of collet allows a reasonably good grip on very thin parts.



Then I installed the pot collet in a collet block and placed it in the mill vise, making sure that it's square with the vise. 



Then I centered the head under the spindle using a DTI against the spigot.  I then drilled the hole pattern using x,y DRO coordinates.  Then I shortened the spigot to the final dimension as shown.



Then testing the fitment against the cylinder.



And testing fitment against the frame.



Now on to the top cylinder head. 

First I used the same pot collet and inserted the raw casting and turned the exposed portion to the required OD.



I didn't show turning the other side of the top head but I did turn the .031" boss as per the print.  Shown is after moving the pot collet setup to the mills and centering the part under the spindle using a DTI.



I didn't show the drilling operation, but it's relatively easy as I could just drill thru the part and into the AL of the pot collet without any problem of damage to the drill.  Shown is the bottom side of the finished part laid on top of the print.



The final pix is the head shown on top of the cylinder to check the fitment.  A miracle occured and it fit properly!!



That's it for today.  Enjoy!

Mike
MIke
Wichita, KS, USA

Offline Admiral_dk

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #42 on: March 04, 2021, 10:43:14 PM »
You are really on a fast track forward with this build Mike and nice looking parts too  :ThumbsUp:

Still following along  :cheers:    :popcorn:

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #43 on: March 05, 2021, 07:31:40 PM »
You are really on a fast track forward with this build Mike and nice looking parts too  :ThumbsUp:

Still following along  :cheers:    :popcorn:

Thanks very much for following along!   

I'm not as fast as it appears!  I'm catching up on several previous weeks of work.  I took pix along the way, but didn't start posting them until fairly recently.  In real time, I'm just finishing the engine, painting, getting a proper base for it, final assembly etc.

Thanks!

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #44 on: March 05, 2021, 08:10:49 PM »
Time for a few more small parts. 

First up are the 2 packing glands.  The first pix shows filing and fettling the parts in my bench vise in order to smooth them up a bit and to get rid of the flashing.



These packing glands about drove me crazy before I got them done.  I tried several things, but what worked, sort of, was super-gluing them to a piece of AL round stock and indicating them to run more or less on center in the lathe.

Super glued to the top of some round stock.



Then centering up the rough part in the lathe.



Then drilling thru one of the glands on the lathe:



Then I turned the part around in a lathe collet to finish the backside off. 



Centering and locating the points to drill thru for the mounting holes.



Somewhere in the process the super glue let go and I had to figure out a way to finish the parts.  Soooo, I ended up clamping the glands on my small tooling plate as shown.



Just a photo of the setup pieces.  The rough bit AL is just some waste material  placed under the part in order to avoid drilling into my tooling plate. 



And finally, the finished glands laid on top of the print.

Pix 1



Pix 2



So my lesson from all this was to not rely on super glue for holding small parts.  I guess I'll either try Loctite 638 or possibly use 60/40 solder to attach the small part to be machined on top of a small scrap of brass.  Any suggestions as to what works best?

Next up is the piston.  I decided not to use the material supplied in the kit as it's 12L14 as near as I can tell.  I had a bit of cast iron bar stock which I prefer for pistons, and started to turn it to diameter.



Trying the turned down section in the cylinder.



I greatly prefer o'rings vs the teflon rings as supplied so I modified the groove dimensions to provide about .005" compression on the oring.  And of course I used only a single o'ring.  I made the groove with a 2 mm grooving/parting tool that can be seen in the photo.



Then after drilling thru the piston, I made the counterbore by holding a 3/8" EM in the tailstock chuck.  I've always had good luck with this method.



And finally for the piston, it's shown against the print assembled with the piston rod and cross slide.



That's it for these small parts.  Next up is the crankshaft but I'll start another post as that item has a lot of steps to complete.

Enjoy!

Mike
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #45 on: March 05, 2021, 08:58:27 PM »
Next up is another of the major components, the crankshaft!!  I decided to try to do the crank as supplied by PMR vs doing a built-up crank.  I'd never done a cast crank so far but I thought it would be good experience and it certainly was that!

Anyway, off we go!  Luckily I have a big enough lathe and a big enough 4J chuck, so i was able to insert the crank all the way thru the hole and just expose the very end to the tooling.  Shown first is turning the end of the crank flat.



Then drilling a center hole.



The same operations were done on each end of the crank.

Then since the crank is/was reasonably straight, I gripped one side of it with 3J chuck and placed a live center in the other end.  Then I used a HSS right hand tool to turn the shaft down to 13/32" in order to be able to use collets. 



Next, i installed the 5C collet setup, turned the crank around and finished the 2nd side to the 13/32" dimension.  This method gets the crank running reasonably true, but not perfectly so.



Then using the same setup, I changed tools back to a carbide insert type and turned the end of the throw smooth.  I went very slowly as this is about as bad an interrupted can as can be!!



Then I turned the sides of the throws to dimension, but they didn't completely clean up. I figured that was ok as I'd rather have the thickness vs the smoothest possible appearance.  I also turned the .125" x .50" 'spacers' leaving a bit more for later turning between centers.  The crank was reversed as required to do each side. 



To turn the chamfer as indicated on the print, I pulled the crank out of the collet a bit and setover the compound to 45" and then just took relatively light passes until the chamfer was achieved.   The part was reversed in the setup to do both side.



The crank shown against the print with the progress on it so far.



Then I setup to turn between centers and started taking down the shaft to .374" as per the print.  Part was reversed as required.I



I used a very sharp carbide insert to bring the center 'spacer' bosses to final dimension and to get them to run true with the rest of the shaft.  I was actually surprised about how true the shaft ran after the previous turning in the collet and live center.  But for sure turning between centers is an excellent method to get the straightest possible result.



Once i got really close to .374" I used some grey Scotch Brite to polish the crank surfaces to a quite smooth condition.



Then a quick test fit on the frame with the crank bearing caps installed.  Success!!  The crank turned quite freely without any slop!



Then over to the mill to remove the small cast in reinforcement bit.  I checked about 25 times to make sure that I milled out the correct bit!    Using the 1/4" EM, I also took the width between the webs to .440" as per the print.  I took this dimension to the top of the rough cast crank journal.



After a bit of cleanup on the belt sander, this is the state of the crankshaft at this point.



I decided to follow the PMR suggestion to make a jig to turn the crank journal.  I won't bore you with all the steps, but i had a bit of 2" material of unknown composition.  I took the OD down to 1.875 and sawed of the indicated amount.



Then, skipping over a bunch of milling operations, we ended up with the final part as per the PMR print.



Then the adapter and crank were placed in the 4J chuck and the adapter was centered.  Note that the crank is well retained by placing it directly under one of the chuck jaws.  Also notice that I put some AL material on that jaw in order to avoid any marking on the crank.



I used a .125" HSS parting blade hung out pretty far in order to clear the throws.  This ended up working pretty well.  I went quite slowly and checked often.  I'd plunge in at one location and then come out and plunge in at another location.  Then I was able to slowly  move the tool sideways taking off .001 or .002 per pass to get to the final dimension.  I didn't show it but I tore off some thin strips of 220 and 320 grit emery cloth and polished the journal to a fairly good finish.

Crankshaft shown against the print.



And lastly shown installed in the frame.



Then I let out a big sigh of relief as this was a pretty tense experience for me.  A part like this requires so much time, a mistake at a late stage of the operations would just about drive one to tears or to drink!

That's it for today.

Enjoy!

Mike

MIke
Wichita, KS, USA

Offline crueby

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #46 on: March 05, 2021, 09:26:46 PM »
Great job on the crankshaft, some delicate work in there!
 :popcorn: :popcorn: :popcorn:

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #47 on: March 05, 2021, 09:57:06 PM »
Great job on the crankshaft, some delicate work in there!
 :popcorn: :popcorn: :popcorn:

Yes sir, turning that crank journal does make a person pucker up!  I wish I had a carbide grooving tool that could reach that deep, but i don't.  I use the groove/turn type tool a lot, and it gives a very good finish and really works well for certain jobs.  Alas, this particular job was just 'A Bridge Too Far' for that tool.  Do you have any suggestions for something better than a big HSS parting tool like I used?

I appreciate you following along!

Mike.
MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #48 on: March 07, 2021, 06:17:20 PM »
Alright, I'm down to the last few parts!  Hopefully we'll get to initial assembly and an initial test run quickly!

First is the eccentric hub.  I'm using the mill as an over the top marking out machine.  I centered up the stock and then from center moved over the spec'd .1875" to get the center of the offset.  I drilled a shallow center hole in order to facilitate the setup on the lathe.  I used the supplied material from the PMR kit, which seems to be free free cutting, possibly 12L14 or maybe 1215.  I can't tell for sure. 



Then over to the lathe with the 4J chuck installed.  I offset the stock until the just created center hole was running true.  I used my home-made spring-loaded centering rod for this.  This actually works quite well and I find it fast to get to a given offset.



Then on to turning the eccentric.  Shown is the point where the cut is just about continuous.



Then drilling and reaming the thru-hole.



I turned the strap area using the 3 mm carbide insert parting tool you see in the pix.  This works well as it's extremely sharp and it can be moved sideways if the cut being taken isn't terribly deep.  I think that this is properly called a 'groove/turn' insert.  I'm about to part the finished piece off.



I didn't show the operation but I drilled and tapped the 5-40 hole using the mill.  The part is shown as completed laid on the print.



And finally the eccentric hub is shown loosely installed on the crankshaft.



Next part to be done is the eccentric cap.  It's shown in the condition as supplied from PMR.  One important point to note is that the hole in the cap as cast, is fairly oblong along the axis of the casting.  This gives allowance fo the part to be split.  Note that this allowance is .125" shown on the print.



The first thing I did was to drill thru with a tapping size drill for the 5-40 screw and then drill to 1/2 the depth with a clearance drill.  Finally the 'bottom' of the hole was tapped thru 5-40.  Since this was a thru hole and the material cut well, I just chucked up the tap and put the mill in neutral and hand rotated the chuck to create the threads.  This is about a a tap as I'd use with this technique.  In any other circumstances, I'd install a tap follower and use a very small tap handle. 



Then I turned the cap sideways and cleaned up the oiler location with an EM prior to drilling and tapping.



I failed to take any pix of drilling/tapping this hole or the hole for the valve eccentric rod, but here's the cap with the valve eccentric rod rod loosely installed in the cap.



Here's a pix of the part as I'm installing it back into the mill.  I blued it up and scribed where the top of the initial cut should be at, more or less!  To align this, I used a 3/8" rod chucked up and just compared each side of the part by eye.  I couldn't come up with any better way to do this as there's really no known flat reference surface to work from, at least the way that I was thinking about it.



Then I installed a .045" slitting saw and gently touched the part with the saw slowly rotating and moved the table down until the top of the cut just intersected the reference line that I had put on the part.



Next was cutting thru the part, manually feeding the saw thru and rotating the saw fairly slowly, somewhere around 300 rpm or so.



Then, since I had to remove a total of approximately .125" of material, and I had just taken out .045, I moved the table up another .080 and made another cut.  You can see the thin waste material after the 2nd cut was made.  I'm always extremely impressed at how smoothly these slitting saws cut.  The finish is almost perfect.



Showing the cap after being split laid out on top of the print.



Just a pix to show what I think is a good practice.  I put small matching punch marks on the bottom of the cap.  The marks won't be seen when the part is installed, but I don't think you can necessarily count on these halfs being capable of being installed 'backwards' without running into fitment issues.  Certainly making match-up marks on big engines and assemblies is a common practice.



Next i clamped the cap down to a bit of scrap AL on my small tooling plate.  I used a DTI to get centered as well as possible under the spindle.  This is a bit of an art as the casting definitely isn't smooth, but as near as I could tell the hole was within about .010" between x and y so it appears that the print was really close when they suggested removing .125" of material when cutting the cap apart.



Next shown is boring the center hole to size using a boring head.  I used the power downfeed and the stop to kick-out the feed at the bottom of the part.  This to me, is one of the best features of the Bridgeport as it takes away any concern about working toward a closed bottom.  Plus the finish that this process creates is usually very good.  The first pass was just taken and you can see that the material being removed is quite even in both x and y.



After the hole was finished, I used a 1/4" carbide EM to take each side of the part to the spec'd thickness.  Since centering isn't critical at this point, I had the luxury of being about to easily remove the part for measurement as I went along.



And finally the cap is shown installed on the hub.  Success on this part!



And now we're down to the last part!  This is the connecting rod and while there are some tricky bits, there's also a couple of features on the casting that make this part a slightly easier.  The first thing I noticed is that the con rod body is almost exactly the same thickness along it's length, after I just very lightly smoothed it with a file.  Shown is the part held on top of a bit of flat 1/4" AL scrap and further held by small toe clamps on my small tooling plate.  I found the center of the small end of the con rod visually using a 1/4" rod held in the chuck and then touched each side of the big end with the same rod in the chuck and moved the end of the part until the DRO was equal on each side of the big end.  I made sure that the top end of the rod remained in its initial position and rechecked both ends several times during this process.  The pix also shows the 1/4" drilled and reamed hole at rod's small end and 2 small center marks representing the top and bottom of the material to be removed.  This is the same deal as the eccentric cap.  There's about .125" of material that can be and needs to be removed when cutting the big end apart. 



Then for reference for the TBD sawing operation, I blued the big end up, drilled the center holes just a bit deeper and then scratched a line in Y across the part. 



I then took the tooling plate from the mill vise and clamped it onto the 90 degree plate.  I ended up edge finding for x and then moving over as necessary but for Y I just used a rod held in the chuck and visually aligned it.  Shown is somewhere in the middle of the drilling and tapping operation.



Then the part was sawn apart using a slitting saw.  I had a reference from the flat at the end of the con rod, but I also was careful to check the saw position against the lines drawn earlier.



Then the tooling plate was moved back to the mill vise and the newly created big end rod cap was fastened back to the con rod body using some 5-40 screws.  One point to note is that the single line and single center mark are actually 1/2 each of the 2 lines and center holes from the previous marking.  This at least confirmed that the sawing operation was correct and the amount of material removed with the slitting saw was spot on!  I was fairly exciting to some this come out as expected!!



The hole was drilled thru and then reamed to the print's spec.



Each end of the rod was milled to the spec'd width.  I used a 1/4" carbide EM for this.  This was pretty stress free for me as the part can be removed, measured and re-clamped down as the alignment is not critical at this point, only the width is.



The hole for the big end rod oiler is drilled and tapped so as to intersect the hole previously drilled from the inside of the rod bearing surface.  Shown is my standard method for small holes, that is a spring tap follower and a very small tap handle. 



The small end of the con rod needs a few more operations in order to create the clamping mechanism for retaining the pin that attaches to the cross slide.  Shown is visually setting the con rod to 45 degrees between the hole centers. 



I didn't take pix of all the operations, but I milled a small flat area and then drilled thru with a tapping size drill, then 1/2 way thru with a clearance drill then tapped the bottom of the hole, all as per the print.  Shown is moving the con rod and a bit of scrap material ot the 90 degree angle plate and visually aligning the screw boss area vertically.  The only critical thing is to make sure that the slot to be created is close to the center of the screw boss area.



Then I put a 1/4" ground pin thru the rod small end and moved the table up just until the bottom of the saw blade was touching the top of the pin.  Since I had the saw blade thickness and the pin diameter I moved the table up until the saw was on center with the rod small end hole and made the cut.



This is the completed connecting rod laid on the print.



And lastly is the assembled 'bottom end' of the engine with the connecting rod, cross head and eccentric assembly all installed and much to my surprise and pleasure, everything at this point, rotated fairly smoothly!!



So now, I'm caught up with posting pix.  Everything from this point is pretty much as its now happening. 

Next up will be the initial assembly, followed by a (hopefully) initial run without all the proper fasteners or gaskets installed, just to check for proper operation and to find and fix any mistakes.

All for today.

Enjoy!!

Mike




MIke
Wichita, KS, USA

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #49 on: March 09, 2021, 04:23:24 PM »
All right!  We're down to the final assembly for trial and the first trial test run!!

For temporary mounting for assembly and testing, I took a piece of scrap 2x4 and used deck screws and some scrap bit of AL to do up some temporary 'toe clamps' to hold the frame.  Not too fancy but they worked.



Then I started assembling the various parts onto the frame.  At this stage I used no gaskets or packing in the glands as I knew I was going to take it completely apart one more time for painting.



I set the piston stroke and locked the piston rod to the cross slide with the jam nut and set the eccentric stroke and the 2 following pix show the stroke of the valve being close to equal when compared to the ports in the valve chest.

One end of the stroke.



The other end of the stroke.



Fully assembled without gaskets, packing, or even all the fasteners! 



And finally, the initial run!  The engine ran well, even leaking quite a bit of air.  I could bring the pressure down to 2 or 3 PSI and it still ticked over.  There's a bit of a knock to my ears that may be either due to slight valve mis-timing or possibly something loose on the con rod.  I'm not sure but I'll check everything for fit as I take it all back apart.

<a href="https://www.youtube.com/watch?v=b9tuNNze7r4" target="_blank">http://www.youtube.com/watch?v=b9tuNNze7r4</a>

Sooo, this project is near to the end.  I'm just waiting on a nice wooden base that my brother's making for me and my son is cutting gaskets for me on his laser cutter.  I'll put a few final photos and a final video in the showcase section whenever I  get all the finishing bits done. 

That's it for today and really for this engine project.

Enjoy!

Mike
MIke
Wichita, KS, USA

Offline crueby

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #50 on: March 09, 2021, 04:41:28 PM »
Terrific! Runs pretty well even without the gaskets, thats a great job!

Online Kim

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #51 on: March 09, 2021, 05:15:05 PM »
Excellent first run!  Now it's time for the happy dance!   :popcorn:

Kim

Offline bent

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #52 on: March 09, 2021, 05:30:58 PM »
Nice job Mike! :cheers:

Offline Johnmcc69

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #53 on: March 12, 2021, 01:34:59 AM »
 :ThumbsUp:
 Great work Mike!
 Can't wait to see it in its finished glory!

 John

Offline b.lindsey

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #54 on: March 12, 2021, 12:31:54 PM »
Very nicely done Mike. One to be proud of for sure!!  :ThumbsUp:

Bill

Offline bent

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #55 on: March 12, 2021, 04:35:33 PM »
" There's a bit of a knock to my ears"

I did the PMR #3 some time ago, and felt the same way...looked more closely at the cross slide and found a little bit of slop (clearance) between the slider and the upper rails.  A bit of tweaking on the spacers did the trick.

Offline mikehinz

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Re: PMR #1 Drilling Engine - Mike's 4th Engine
« Reply #56 on: March 13, 2021, 12:11:57 AM »
Thanks to everyone that's taken a look at this build!  I really appreciate it!  And i'm very glad to get to a pretty well running completed engine.

I"m just in the process of posting the finished engine pix to the showcase as well as a video of it running in its finished condition.

Again, thanks very much for stopping by to take a look!

Mike
MIke
Wichita, KS, USA

 

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