Upshur Horizontal Farm Engine - Mike's Version

[mikehinz]

This post will cover making the valve push rod and is quite short as it's one of the more simple parts.

I cut a piece of 3/32' drill rod to length as per the drawing, and used a die to make 3-48 threads using my home-made tail stock die holder.  Shown is just after cutting the threads.  For this sort of small thread, I just rotated the die holder by hand.  I did apply a bit of EP-Extreme Tap Magic prior to threading.



Here's a better pix of my die holder.  All home made.  One end holds 1" dies and the other end holds 13/16" dies.  This is one of the more useful tools I've made for making parts for these small model engines.



And here's the finished valve rod laid on top of the print.



That's it for this simple part!

Enjoy!

MIke

[mikehinz]

This post will go over the gear assemblies and cam.  Note that I use the word 'gear assembly' as I actually purchased the gears and then made hubs and assembled them along with the cam. 

I must hang my head in shame as I've not yet cut any gears myself.  I intend to one of these days, but I need to purchase some gear cutters and am wading through the choices there, and I bought a kit to automate my rotary table and I've not build and install that bit of gear.  I'm thinking about purchasing some import module vs diametrical pitch cutters just due to the price difference between the two.  I think I'll probably eventually purchase some module .8 (roughly equivalent to 32dp) 20PA.  If anyone has any good advice for what's best, I'm all ears!  But I sort of have the excuse that purchasing gears for a few engines is actually cheaper than buying cutters! 

So for this engine, I purchased 2 gears from PIC Design, models J23-20 and J23-40.  These are 1/8" face width, 32DP, 20PA one 20 tooth and the other 40 tooth.  These are both unhardened 303 stainless, hubless with a .375" hole.  These are exactly the same pitch diameter as the 48t gears originally spec'd on Upshur's plans. 

For the crankshaft gear, I made a steel hub since it will be held to the crankshaft with a setscrew.  Here's the first pix.  I'd already turned the ODs, the smaller bit to fit within the gear and the larger OD to allow enough meat for a set screw.  Shown is tapping the 4-40 hole for the set screw.



Here's the gear and the hub I made for it.



Here's the gear on the print after pressing the hub into the gear with a little Loctite 638 applied before being pressed together.



And finally this gear being test fit to the crankshaft.  One of the reasons I built the gear this way vs what Upshur calls for, is that this makes the exhaust timing super easy and easy to adjust as needed vs the fixed arrangement method. 



Next up is the cam gear and cam.  Luckily, when I built my Webster engine, I cut the cam stock long enough to make an extra cam.  Originally I did this in case I needed to change something on the Webster.  But it turns out that the Upshur cam design is exactly the same as the Webster, so all I had to do was to part off another piece of the cam previously made.  That's what's shown in the pix.  That's my favorite 2mm carbide parting tool in action!



And the cam after parting off and cleaning up on a Scotch Brite wheel.  It came out well.



And here are the 3 parts necessary to assemble the cam gear and cam.  I made a small combination hub out of SAE 660 bearing bronze, one end .375" and the other .437".  The reason for using bearing bronze and using this method, is that the gear and cam have to rotate on the camshaft so it's way better to use bearing bronze for this application vs steel on steel.



And here's the assembled cam, cam gear, and hub.   The pieces were pressed together using some Loctite 638.



And here's a bit of a family photo of both gears along with the crankshaft bearing carriers with the bearings installed.



And that's it for the gears.

Enjoy!

Mike

[mikehinz]

For my last part for today, I'll show how I made the hit-n-miss spool.  This is definitely different than Upshur's design in that it has 2 sections to separately guide the weight arms and the activation lever.   The challenge here is that this is wider than Upshur's design so I carefully modeled all this in CAD and increased the left side of the crankshaft enough to accomodate this part.  Just as a warning, this causes other subtle changes so don't follow my path unless you're willing to carefully model this all out.

I started with a piece of SAE 660 bearing bronze that as you can see, is quite beat up, but luckily it's quite a bit oversize so I could easily turn the OD to the required diameter.



I turned the OD with a standard CCGT insert tool and then cut the groove using a 2mm carbide part/groove/turn tool.  I also drilled and reamed the ID .001" over so it would easily slide on the crankshaft.  The pix shows the start of the parting off operation.



Here's the finished part on the print.  The print shows my almost illegible scribbling giving the DRO readings for the various features.  I normally try to dimension the drawings using ordinate dimensions so I can directly use them with my DRO, but for whatever reason I didn't do that for this item.



And finally the finished hit-n-miss spool fitting to the crankshaft.



That's it for today!

Enjoy!

Mike

[Kim]

That's a lot of nice little parts, Mike! 
Kim

[mikehinz]

Here's the build log for a few more small parts. 

First up is the clevis for the valve rod end that will attach to the rocker arm.  I started by cutting off a piece of 1/4" square stock a bit long and placing it in the mill vise, making sure it was vertical.



Then milling the slot in the end stock to start forming the clevis.  I'm using a 2 flute HSS end mill turning about as fast as my mill can go.



Then I drilled thru both sides for tapping one size 2-56 and then drilling a clearance size hole on the other side.  Shown is tapping the bottom side hole.  I just placed the mill spindle in neutral and rotated the chuck by hand.  This works quite well for thru holes.



For rounding the end, I blued the part and marked the radius with a gage and a sharp scriber.



Here's the marked part ready for the belt grinder.



And here you can see the part about to have the end rounded on the belt grinder.  You can see why I left the part long as I needed something to grip while doing the rounding operation.



Here's the part mounted in the lathe in a square 5C collet.  I parted it off to length and then drilled and tapped 3-48 as per the drawing.  That's a spring loaded tap follower mounted a tailstock chuck along with a very small tap handle.  I find that this combo gives a very good feel when tapping small sizes. 



Here's the finished part on the print.



And last up for this part.  It's mounted on the valve rod and I've installed the 2-56 threaded shoulder screw and luckily everything fits!



And now onto the exhaust pipe.  This is a very simple part so I don't show any of the operations to make it.  Essentially it's just a piece of .25" brass stock, cut to length, threaded 1/4-32 for .25" on one end and drilled thru.  I decided to thread this part since the I noticed that on my Webster engine, the exhaust pipe tended to loosen when only secured with Loctite.



Next up is the rocker arm post.  I didn't show the turning operation but it's just a piece of .25" drill rod with the end of turned to .187" OD.  Shown here is milling off 1/2 the thickness of the .25" end.  I'm holding the work in a collet block as I find it very easy and handy for small parts. 



I didn't show the operation, but I drilled and tapped a 2-56 hole in the center of the flat.  Here's the finished part laid on the part.



And here's the rocker post test fitting into the head.



And here's a tip for any future builders.  The original Upshur prints show a .1875" drilled and reamed hole all the way thru the head.  I'd recommend NOT drilling thru the head and shortening the rocker post by an equivalent amount.  This prevents a potential leak point.

And one last part for today.  These are the valve guides.  I didn't show any of the operations making them as it was pretty much all simple turning, drilling, and reaming.  I made these from a small piece of aluminum bronze that I had on hand.  I did change these from Upshur's original design in one aspect.  I added a 2.5" degree taper to the end of the guides.  This helps eliminate spring binding and IMO this is important as the springs are quite short and they may get excessively stiff due to lack of travel if the ends bind on the guides.  This taper prevents this. 



So that should do it for today.

Enjoy!

Mike

[Admiral_dk]

You have been busy with small parts - something many here take a lot longer to finish 

[mikehinz]

Today's post will cover a few more small parts that I've just finished.

First is a pix of everything I've made so far assembled to check fit.  A minor miracle has occurred and everything fits and turns.  There's no piston or con rod at this point so what I'm checking here is the fitment of the cylinder and head to the frame and the gears and cam. 



Next I'll show how I made the rocker arm.  I started with a piece of steel I had on hand, and brought it to the general length and width of the rocker arm.  Notice that I've left it long.  I'm showing drilling the two holes in the to be rocker arm, the center for the pivot point and the one on the end for the clevis attachment.



Next I used an end mill to form the radii at each of two points as per the print.  I located the points using the DRO and then moved in y axis until I reached the depth as per the drawing. 



This is how the work looks at this point in the operation when viewed from the backside of the mill.  I think this shows more clearly what's going on to this point.



Then I used a slitting saw to cut off the part to the required thickness, I think it was .094" .  As usual, I'm always amazed at what a great finish a slitting saw produces.  You can probably see where I"m going with this...............



The part on the print after I cut if off the base stock.



And finally the finished rocker arm after I rounded the ends on the belt sander and on a Scotch Brite wheel.  I'd blued and marked the area to be rounded with a radius gage.  I think the rocker arm came out pretty good and making it the way I did nicely solved the problem of how to grip a small part.



And here's the rocker arm, clevis, post, and valve rod all assembled.



With the rocker arm done, I started on the hit-n-miss lockout lever.  I ended up using pretty well the same technique as I did for the rocker arm, so here goes.

I cut out a piece of steel and brought to the overall dimensions using the mill and you'll note a hole drilled from the end which becomes the pivot point in the finished part.  I didn't show milling the stock to dimension or drilling the hole.  What's shown here is milling away the material from one side of the stock to form the 'catch' bit of the lever. 



There's a flat area at one of the lever so what's shown is milling that area to depth.



The remaining portion of that side of the lever needs to milled at a 15 degree angle.  Shown is a 10 degree plus 5 degree angle block set on top of the work and indicated to be level with a DTI.  This assures that the material will be milled away to the 15 degree angle.  This angle isn't terribly critical so it wasn't probably necessary to get this accurate. 



And here's the part on the print with the work so far.  I did it this way as holding a small thin part like this would otherwise be difficult.



And then back into the mill vise, the flat side against the fixed jaw and a liberal amount of Al packing to secure the part against the moveable jaw.  I'm using a slitting saw to part off the lever to .094" thickness. 



The finished lever after rounding off the end with the belt sander.  The tip shape will be refined whenever I actually try to make the hit-n-miss mechanism work.



And lastly for the lever, a pix of it installed on the engine.  Certainly it fits, but that's no guarantee that it will actually work.  That bridge will be crossed later, hopefully successfully. 



And lastly for today's posts will be the piston and wrist pin. 

The wrist pin is just a piece of drill rod cut to length with the ends rounded. 



I made a corner rounding tool some time back as shown here.  It's a bit rough, but it works.  After I cut the rounded profile, I filed it a bit and then used some emery cloth on it and finally finished it with some maroon Scotch Brite. 



Next is the piston.  I didn't show any of the operations as this is a very simple design.  Everything was done on the lathe, except for the wrist pin hole.  I did that on the mill holding the piston with a collet block and drilling and reaming thru .001" undersize.  I did want to point out the dimensional details for the o-ring groove.  I use the method espoused by Bob Nawa which calls for a minimal radial compression on the o-ring only .004 to .005"  If you look at the attached pix, you can see my drawing notes on how to form the groove.  I used a 1/16" x 3/4" OD nominal Viton o-ring and based on my finished cylinder ID of .7505" the o-ring groove depth and OD is calculated.  When I cut the groove, I used my 2mm carbide grooving/parting tool and carefully progressed it while carefully measuring the groove diameter.  I was happy to land right on the spec'd OD at the end.



And finally the piston is shown fitted into the cylinder.  It fits well, being a nice slip fit.  It's actually .002" under the cylinder ID which is exactly what Upshur spec'd on his original prints.  I went with the Al for the cylinder since that's what Upshur specified, but I personally like cast iron for pistons better as I think they can be fit a bit closer with very little tendency to gall.



And that's it for today! 

Enjoy!

Mike

[RReid]

Lookin' good, Mike. You're making rapid progress! 
I'm not building mine as a hit & miss, so I get to skip that lever,

[mikehinz]

This post will go over making the connecting rod.  I modified this extensively from Upshur's original plans, mostly because I wanted to, but also because I thought some aspects of the original design wouldn't stand up well over time.  Unfortunately the side effects of my modifications were added complication and added time to build it.  But in any case, here goes!

I started with a piece of 5/16" thick Al and after squaring it up and bringing it to the spec'd dimensions, I drilled and tapped w holes for the ron rod cap bolts, the top portion being drilled out clearance size for 4-40.  I also drilled a small center hole in what will shortly become the rod cap.



Then I used a slitting saw and cut off the rod cap.



The rod and rod cap shown on the print.  You can see the clearance size holes in what will be the rod cap and the 4-40 tapped holes in what will become the rod body.



I made some 4-40 threaded studs from a bit of brass.  I very carefully turned a piece of .125" rod down to .112" and then thread it with my home-made tail stock die holder.   You'll see the reason for making these studs shortly.



And the two pieces reattached using the studs and some model pattern nuts.



Back to the mill locating a number of features and drilling center holes at 4 points to define the to-be shape of the con rod.  I also carefully located, drilled, and reamed the holes for the wrist pin and for the big end.  These are larger than Upshur's original plans called for and you'll see why shortly.



Here you can see the big end after reaming to the final size, which in this case is .4375".  You can see why I used brass studs as they are partially cut when reaming to the final size.  I also increased the rod cap thickness a bit as I needed more meat on that piece given the much larger hole in the big end.



I also milled an extra feature on the top end, essentially a 5/16" square extension as the original stock is 5/16" thick.



Then I installed my small tooling plate and located the big end and also made sure the part was parallel to the x axis using a DTI.



Next I plunged in a .25" 2 flute end mill at the 4 locations previously located.  I actually didn't need to locate them earlier as I used the DRO again this time and used an end mill anyway.  The 4 cuts start to define the to-be shape of the con rod.



And here you can see the rod with the operations done so far laid on the print for comparison.



And here you can see the reason for the larger hole at the wrist pin end.  I turned a simple bushing from SAE 660 bearing bronze and you can see it here laid near the con rod.



And here it is pressed in place with a little Loctite 638 applied before pressing in place.



And here's the start of milling one side of the con rod to a 2 degree angle with respect to the centerline.  I'm using a 3/8" 4 flute end mill and I placed a 2 degree angle block under the part. 



Then I turned the part over and this time placed a 4 degree block on top of the previously milled edge and set it level using a DTI.  If the starts are aligned, this should also give a 2 degree angle on this side of the con rod.



And the con rod against the print with the operations done so far.  You can start to see where this is going!



Now over to the lathe.  You can see the reason for both the center hole in the rod cap and for the mysterious 5/16" feature milled on the top of the rod.  I'm holding that end is a 5/16" square 5c collet.



Here's some of the lathe work.  I rounded the wrist pin end with a right hand tool, but had to change to a left hand tool to round the big end of the rod.  I'm using a CCGT insert in a 5/8" shank tool holder.  I find that these inserts work very, very well on Al.



Here's a pix of the current progress on the rod when laid on the print.



And here's another pix from the rod's side so that you can see the shape from this perspective.



And by now probably everyone has figured out that I'm gong to attempt to make and install a split bronze bushing for the big end of this con rod.  So I had a piece of 3/4" SAE 660 bearing bronze and shown is turning it down to .625" to start the process of making the split bushing.   Shown is a short length turned to .625" and being parted off.



And here's the bearing bronze shown on top of the print which shows how the bushing will be made.



Then over to the mill with the stock installed in a collet block and being split as deeply as I could with a slitting saw.  I used the thinnest saw I had, .012" so that I removed the smallest amount of material possible.



And the split bearing bronze after parting it off from the main bit of stock.



Over to the welding table showing the materials I'll be using.  I've roughed up the flat sides of both pieces using some 120 grit emery.  For this sort of soldering, I like to use the 'tinning flux' type material as it has some finely ground solder within the flux.  I'm also using the Harris 4% silver "lead free" plumber's solder.  I find that this solder melts beautifully and bonds well.



After fluxing both halves of the bronze material.



And here's the operation ready to proceed.  I secured the two halves together with a couple of twists of some annealed steel wire.  Heat will be applied by this very standard plumber's torch.



And here's the part after soldering.  I applied heat to the body of the part and then touched the solder to the top of the 2 pieces when they got hot enough.  The solder wicked completely through both parts and was visible at the side seam and at the bottom of the parts when completed.  This is the top of the part after soldering.



And here you can see the bottom of the part after soldering.  Notice the solder flowed completely through the joint.



Since the part is not truly round anymore, I went back to the lathe and was still able to grip it with a 5/8" collet even though it's oblong about the amount of the cut.  During this operation, I took the OD down to .562", still oversize for where I need to end up, but now that end is completely round.



And here's the bronze after turning one end back to round.  The solder joint is barely visible after turning the OD down.



I didn't show the operations on the lathe was it was just some turning to the final OD and creating the .437 OD with a groove/turn/parting tool.  Here's the bronze to-be bearing on the print.



Next was over to the mill with the part installed in a collet block.  Shown is aligning the solder line as close to horizontal as possible, just by eye and comparing it with a parallel for reference.  After I got it as close as possible, I took it back out of the vise and tightened the collet securely.



Then I created the relief areas for the 4-40 cap screws by plunging in with a .125" end mill.  I located the end of the part and the centerline and using the DRO to place the cutter appropriately.



Checking the fit of the con rod big end on the bushing.  I wanted to make sure there was sufficient clearance for the cap screws before tearing the setup down.



And here's the bushing on the print showing the relief areas.



I didn't show the remaining operations on the lathe.  I was going to but things happened rather fast.  First I drilled thru the part and then reaming it .001" under 5/16".  I then went to part off the bushing and just when the parting operation completed, the part actually split right at the solder line.  I think what happened was that there simply wasn't enough material left to withstand the pressure from the parting operation.  But luckily the bushing halves were completely fine and their shown against the print, along with the con rod and the brass studs that were sacrificed during drilling/reaming the big end of the rod.



Then back to the rod.  Here's the setup to remove the holding piece from the small end of the round and to round it over.  I made an alignment pin for the center of the rotary table, .75" by .1875" to center the rod.  Then I placed a scrap piece of Al under the rod and secured it with a couple of toe clamps, centered the RT under the spindle, moved off by the radius in y and rotated the RT to round the end.



And here's the rod with the small end rounded.  It's interesting how the two rounded features intersect and make what I think is a rather nice looking feature.



Here's a close up view of the small end of the rod with the operations done so far.



Next the thickness of the rod body needs to be reduced from .3125 to .25" everywhere except at the small end.  So I reinstalled it on the rotary table, moved out the radius plus 1/2 the cutter diameter and rotated the table 360.  I repeated the same operation on the other side of the rod also.



And here's the small end after thinning both side using the rotary table. 



Then back to the tooling plate to then the remaining sides of the rod.  I secured it and then moved the toe clamps as necessary to get to all parts of the rod body.  When I flipped it over, I placed a bit of flat, scrap Al under the previously milled area and moved the clamps as required to remove the material from the current side.



And here's the rod profile after the thinning operation was completed.



Then, since the bushing isn't guaranteed to be perfectly round, and I'd reamed it undersize, I then reamed it first to 5/16" and then finally to .001" over size.  I did this just by hand with the reamer in the bench vise and turning the rod by hand.



Lastly, I drilled a 1/16" oil hole in both the small end and the big end.  My thought is that I can periodically put a drop of oil on both of these locations and hopefully that will be good enough given this is bearing bronze.  The bushing halves fit quite securely in the rod and rod cap but I also put a small drop of Loctite 638 under each half of the bushing prior to installing and tightening down the rod cap. 



And here's the wrist pin, piston, and con rod ready for assembly.



And here's all the major parts assembled and checked for rotation.  I do notice that the piston skirt protrudes below the cylinder bottom by about .20" or so.  Is that correct?  I can't find any mistakes in the dimension so I assume so, but I'd like to be sure.



And here's a pix from the top when at TDC.  The piston is also about .20" below the top face of the cylinder which I also assume to be correct, but I'd like anyone with experience with this engine to comment.



And that's finally it! 

One of the other reasons I built the con rod this way is that I next want to build a Farm Boy and the con rod design for that engine is very similar to the way I built this one so I felt that this was a good way to gain experience.

Sorry for the length of this post, but I did want to give sufficient detail for others to attempt the same.

Enjoy!

Mike

[crueby]

Great sequence, great results!
 

[RReid]

Nice job on the con rod, Mike! 
The fun part of our semi-parallel builds is seeing the outcome of our sometimes different approaches to the same part.

[mikehinz]

Nice job on the con rod, Mike! 
The fun part of our semi-parallel builds is seeing the outcome of our sometimes different approaches to the same part.

Yes, it's actually quite interesting to see how differently a part with the same functionality can be done so differently!  I like your approach quite a bit and a thought about making the con rod about the same way that you did out of a piece of Al bronze, but I wanted to go the lighter weight approach and I wanted to practice for the Farm Boy engine that I want to attempt someday.

Keep up the good work on your engine!

Mike

[Kim]

Great write-up, Mike, and a good set of ops to get it done.  I appreciated your step-by-step approach! 

Kim

[RReid]

And here's all the major parts assembled and checked for rotation.  I do notice that the piston skirt protrudes below the cylinder bottom by about .20" or so.  Is that correct?  I can't find any mistakes in the dimension so I assume so, but I'd like to be sure.

Hi Mike. I got my piston made yesterday, and assembled it all together earlier today. My piston skirt also protrudes about the same amount out the bottom.

And here's a pix from the top when at TDC.  The piston is also about .20" below the top face of the cylinder which I also assume to be correct, but I'd like anyone with experience with this engine to comment.

My piston is 0.312" below the top of the cylinder at TDC. That seems like a big difference. Did you measure yours, or just eye ball it? I checked all my relevant parts against the drawings and can't find an error.

[mikehinz]

And here's all the major parts assembled and checked for rotation.  I do notice that the piston skirt protrudes below the cylinder bottom by about .20" or so.  Is that correct?  I can't find any mistakes in the dimension so I assume so, but I'd like to be sure.

Hi Mike. I got my piston made yesterday, and assembled it all together earlier today. My piston skirt also protrudes about the same amount out the bottom.

And here's a pix from the top when at TDC.  The piston is also about .20" below the top face of the cylinder which I also assume to be correct, but I'd like anyone with experience with this engine to comment.

My piston is 0.312" below the top of the cylinder at TDC. That seems like a big difference. Did you measure yours, or just eye ball it? I checked all my relevant parts against the drawings and can't find an error.

Ron, in the morning, I'll pull the head off and check the distance from the top of the cylinder to the top of the piston at TDC.  I'll report back here on the exact measurement.  I was just eyeballing it when I said .20" originally.

FYI.

Mike