# Joy's Valve Gear Horizontal Engine



## kvom (Apr 29, 2014)

I've had this engine on my "want" list for a few years having seen a completed model in past years at both NAMES and Cabin Fever.  So this year at NAMES I picked up the casting set.  I had purchased the drawings earlier from Dennis Howe at HistoricModelsandReproductions.com.

At the show I met Lee Whelan who built the working model I'd seen, and also another gentleman who had also completed it.  Both assured me that it should be easy to get running with some case.

Here's a video I made of Lee's model at the show.

[ame]https://www.youtube.com/watch?v=e4GCgJTv5wk&feature=youtu.be[/ame]

Some still photos of the engine as well:  http://www.pbase.com/kvom/joys_valve_gear_engine

I'll post some photos of the castings a bit later.  I'm not sure when I'll start this build as I have a number of other projects to wrap up.


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## Philjoe5 (Apr 29, 2014)

I've always admired this engine.  I saw it at NAMES some time ago and had often thought it might make a good project when my skills had improved.

I'll be looking in on this project and wish you the best of success in building it.

Cheers,
Phil


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## Charles Lamont (Apr 30, 2014)

That is a very nice model. Considering what such an engine might have done in full size, twin cylinders and reversing gear suggest either a (colliery) winding engine or more likely a rolling-mill engine. I don't know what other applications there were for reversing stationary engines. Either way, two flywheels, and crowned ones at that, seem unlikely: for either winding or rolling, a geared drive would be more probable than a belt. On the other hand, of course, there is no rule that obliges you to pay the slightest attention to authenticity.


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## kvom (Apr 30, 2014)

The prototype is the same size as the model, and was designed from scratch by Mr. H. Muncaster.  To quote from his article in (March, 1905) _Model Engineer and Electrician_, "In a sense the engine is not a model.  It was made with an idea to produce a small engine that would not merely be a plaything and a source of amusement, but would also be capable of useful work, if required to drive a small lathe, or for any other duties to which it might be applied."

Unpacked the castings for inspection.


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## kvom (May 6, 2014)

Took some evening free time to model the conrods in Cubify:






In my view this may be the most difficult or time-consuming pair of parts to make,  The bounding box for stock is a 1.5" square bar 10.5" long, or 23.625 cubic inches.  The volume of the finished bar is 2.6 cubic inches, so 89% of the material is to be milled into swarf.  Not to mention that the fixturing for the various ops.  One option that might work better is to machine the U-shaped end separately, as long as there's a way to accurately attach it to the rest of the rod.  Probably best to rough it out and then finish so that the cross hole is drilled perpendicular to the rod surface.  It might even be best to fabricate as 3 separate pieces.

OTOH I've just reviewed Simon's posts on fabricating his half-scale rods, so following his operation order makes in look reasonable, esp. as with a CNC mill I'll avoid needed any rotary table setups.

I've read about people using Shapeways to 3D print various parts, esp. for casting patterns, so I uploaded the STL file to get an idea of pricing.  Printing one of these in steel would cost $350!  That would be a last-hope option.


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## Rivergypsy (May 6, 2014)

Kvom, just leave some useful holding stock and you'll be fine. Trim it back bit by bit and there's no worries. It worked on our compound anyway ;o)


Sent from my iPod touch using Model Engines


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## bananarchy (May 7, 2014)

I'm definitely going to be following this closely - I really like that engine. I think my next undertaking will be a Stuart No. 1, but this is very appealing as well. I may just have to build both of them


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## kvom (May 23, 2014)

Waiting on other things to make progress on, I decided to start roughing the cylinder casting.  There's a fair amount of extra material in all dimensions, so squaring the block doesn't require a huge degree of precision.  I used the vertical walls in the sides as a guide and took off the draft material for the top and bottom with a small 2-insert face mill on the Bridgeport.  This was not an especially pleasant operation with hot chips flying about, so I've decided to wait until the CNC mill is back in operation to mill the front and back.  My intention is to surface grind these 4 surfaces and their mates so that gaskets won't be required.  

Today I spent an hour or so grinding the top/bottom to ensure they are flat and parallel.  The old grinder still does a decent job as measured thickness  on either end is less than .001 difference.  Currently 3.407" thick, the final dimension is 3.375.  I'll use the top surface as the reference for boring the cylinders, and then machine/grind the bottom at the end.


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## kvom (May 25, 2014)

Worked on two more castings the past couple of days: the steam chest and its cover.  Working with cast iron is dirty work!






All the mating surfaces are ground, so should seal air-tight without gaskets.  Cranking the handles on a manual grinder is somehow hypnotic after a while.

The drawings suggest drilling the chest's mounting holes so that they appear centered in the bosses.  Therefore the corresponding holes in the cylinder block and valve plate will need to to located using transfer punches


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## kvom (May 26, 2014)

Bit of a problem today as I was squaring up the cylibnder block.  Seems to be a bad spot in a potentially bad place:






The cast hole is only 1.25" diameter while the target bore is 2".  Nevertheless the bad iron is within the circumference.  I'm hoping that it's less than .44" deep, since the boundary of the cylinder bore itself starts that far inside.  The outer .44" is slightly larger.  The steam ports are in this portion, so drilling them doesn't cause a burr in the cylinder.

My plan is to square the sides and locate the actual center of the bore, the CNC mill a 1.95" hole .4" deep.  That should tell me if the occlusion would extend into the bore itself.


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## kvom (Jun 3, 2014)

After some email discussion with Dennis Howe, I have decided to bore the casting oversize and use CI sleeves on both cylinders.  An advantage of this in any case is that I can bore the cylinder casting on the mill without too much concern about finish, and turn/bore the sleeves on the lathe where I can a very good finish more easily.

Today's project was simple parts:  the rear cylinder heads.  They could me made fairly easily with some steel rounds, but the casting set contains two cast "cookies".  As a first step, I clamped them in the Bridgeport vise, found a close approximation of center, and drilled the 6 mounting holes.  I then made a "fixture" for holding them on the lathe.











Now I could turn the side draft angle square, and obtain the approximate final diameter.






With a good perimeter surface, face both sides.






Screw the two parts together using the fixture and turn both to final diameter at the same time.






Now face to thickness and  then reduce the flange area.






Finally, grind both sides flat.


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## kvom (Jun 3, 2014)

Started on the front cylinder heads, which are more complex.  First steps are similar to the rear heads.  Using the fixture to  square up rough dimensions.
















All the drilling and boring of the head will take place with it bolted to the cylinder, in order to get everything concentric.


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## Charles Lamont (Jun 4, 2014)

<pedant mode> In British English at least, on a steam engine these are "cylinder covers". </pedant mode>


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## kvom (Jun 6, 2014)

Made a start on one of the flywheel castings.  They are 9.25" diameter raw to be machined down to 9", and pretty hefty.  I figured to use the inter-spoke space to mount on the lathe, so filed down the join lines.






Turns out I needed to use the outer ends of the chuck jaws on the inner surface of the rim.  Got it running fairly true and centered after some fiddling, then step drilled the center hole to 11/16" and reamed 3/4.






Then faced the rim and hub, bored the inner rim flat, and turned half the outer rim.  No way on this lathe to get the tool to reach the entire width of the wheel.






I figured that with the center hole reamed, I could always make a mandrel to turn the other side, but to my surprise/delight, mounting in reverse and using a bull center in the tailstock to apply pressure, the wheel turned perfectly true.  So I did the same ops on the other side.  

After removing from the lathe, I could determine the needed finishing cuts to bring to final dimensions.  In reality, nothing is critical, but the plans call for the ends of the hubs to be inset from the edge of the rim by 1/8" on each side.  I'll do the measurements the before the next session.


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## kvom (Jun 8, 2014)

Yesterday worked on the second flywheel in the same manner as the first.  Got this one closer to plan dimensions.  Should get some 3/4" drill rod delivered tomorrow to make a test axle and test how true they actually are.

Today I did the basic machining on the two journal cap castings.  Simple machining to mill the top and bottom flats and drill the clearance holes for the 3/16" studs.  They still need a shallow slot milled in the base to clamp on the crank bearing, but this will be done to fit during assembly.






Almost have my nerve up to start machining the big base casting, as I have a plan pretty much decided on.


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## kvom (Jun 9, 2014)

I've been thinking about how to fixture the conrods for CNC milling, and came up with this:






Starting with a 13" length of 1.625" diameter stressproof steel rod, mill the two 1" cubes on each end, and cross drill the .5" holes in each.  With an appropriate fixture block on each end, the stock can be bolted down to expose any of the 4 sides to the spindle.

The steps used to draw the model match the steps needed to machine the part.  Once at the stage shown, the blocks on the end can be cut off and the slots on either end milled.


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## kvom (Jun 10, 2014)

I received the raw material for the cylinder sleeves - 1 ft length of 2.5" diameter durabar cast iron.  I sawed off two 5" pieces, faced the ends, and wanted to see how accurately I could turn the diameter needing to turn partially from each end.  The accuracy of the lathe and the chuck were quite good.  When I swapped ends and turned without moving the cross slide, the machined sections matched to less than a thou.  So here's a short afternoon's product:






The plan for now is to bore the cylinder block on the mill to a maximum diameter of 2.375" (any larger starts ti encroach on the covers' mounting holes.  Then turn the sleeves to a good sliding fit.  Then drill/bore the sleeves on the lathe to 2" diameter and secure to the block with loctite.  The pistons will then be turned to fit the sleeve bores.


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## kvom (Jun 11, 2014)

Short session in the shop.  I was a little tires of machining CI, so decided to turn the piston rods.  These are from .375" 303 stainless rod.  I got the polished rod figuring that having good tolerance passing the packing gland couldn't hurt.  Threads are 3/8-24 and 5/16-18.  I single pointed partial threads to ensure straightness, then finished with dies.






I also got polished 1/4" 303 for the valve rods for next time.


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## kvom (Jun 17, 2014)

Some minor progress from the weekend - 

Turned the valve rods from 1/4" SS 303 rod, and threaded 1/4-28.  Single pointed the threads about 89% and finished with a die.

The  turned from cylinder covers/heads to plan dimensions.  Used a 1/8" cutoff tool to do the necking.


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## kvom (Jun 17, 2014)

Took a deep breath and decided to start machining on the base casting.  Nothing on it is difficult, but accuracy looks to be important.  It will also be an expensive casting to replace if I mess up.

It just fits in a 6" Kurt vise.  It needs to be sitting level to machine the mounting surfaces, so I compared the vise level:






:

To the top of the casting:






Drilled the 6 5/16" holes for connecting the base to a sub-base, and roughed out the holes for the valve links and exhaust.  I will finish the profiles to be symmetric to the centerline once I locate it.






My intention is to do all surfacing, drilling, and tapping on this casting without removing it from the vise.  Since the range of holes on the X axis is 17 inches, I made sure the casting was positioned to reach everything.


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## kvom (Jun 17, 2014)

Next I measured the relative heights of the 3 flat surfaces that will have tapped holes.  The left side mounts the cylinder; the center has the crosshead guides and valve pedestals, and the right is the top of the main bearings.  The unmachined surfaces are quite close to their relative differences per plan, withing .030".







Next I used a small face mill to flatten each of the surfaces, taking the minimum needed.  This meant removing only about .020" max.  Then machined the faces of the bearing stands and both sides to a depth of 1.40" and keeping the width of the stands at 1.25".  I managed to hit the front one pretty dead on, but the back ended up 8 thou thinner.  I'll need to make the grooves in the bearings to match.






The next major step is machining the openings in the stands for the bearings.  Once done, the bottom of the opening becomes the reference datum for facing the other two mounting surfaces.  The center of the opening becomes the zero point of the x-axis, and the two outer faces of the stands become the datums for determining the engine centerline.  All the mounting holes are positioned using this derived point in the XY plane and should help ensure that all the motion gear is straight and parallel.


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## kvom (Jun 18, 2014)

Lots of cranking the dials today, but the machining on the top of the base casting seems done.  Milled the slots for the main bearings, leveled the two other mounting surfaces, machined the slots for the crosshead guide, and cleaned up the three square openings.

Next session will be drilling and tapping the various mounting holes.


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## kvom (Jun 28, 2014)

I finished the work on the base casting a few days ago.  Only needed drilling and tapping on the top.






Then reversed using the machined mounting surface. I used a jack screw on one end to shim it level along the length, needing only about 20 thou of machining across the entire surface.  Finally just needed to tap the through hole where the radius rod pivot block will be attached.


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## kvom (Jul 3, 2014)

Working on the rocker slide frames the past few sessions - awkward castings.  Got all the outer dimensions machined plus the holes for the shafts and rocker mounting screws.  Now need to widen the inner opening and mill slots for the rocker slides.


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## kvom (Jul 6, 2014)

Machining the shallow slots used to align the rocker guides in these frames using a 1x1/4" keyseat cutter bought specifically for this job.

With a piece of 3/8" drill rod for guidance, touch off the bottom of the cutter.






Then lower the tool by half the cutter (1/8") plus half the drill rod diameter (3/16) and the slot center will be centered on the hole.  Need three passes to cut the 5/8" wide slots on each side.











Then started on the valve journals, two castings:






To be able to hold the casting easier cut out bottom of an aluminum soft jaw,






Clamped upside down using eyeball to position, then trued up the base.






Then holding the base, faced off the bosses on both sides.






Drilled and reamed the boss getting as close to the center of the milled circle as possible by eye and DRO, then trimmed the base to give the center its correct distance from the hole.






Then used the drill rod to find the center in order to drill the clearance holes in the base.  Luckily I had a long center drill to be able to reach.






After that I had a disaster and ruined the second casting, so it was time to stop for the day.  If I can't get a replacement casting I can machine the matching part from stock.


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## kvom (Jul 19, 2014)

With CNC mill back in operation, I decided to make the slider guides.  These are to be made from bearing  bronze, which seems to be available only as round stock, not square bars.  I have a piece of 2-1/8" round, and verified via CAD that I could make the 4 necessary pieces using that cross section with one 2.5" length.  So clamped in the vise and milled a flat on both sides.






Nww Milled the profiles for 2 guides and drilled the mounting holes.  Endmill is 3/16" carbide.






Turned the rod 180 degrees for the other two.  Used a height gauge to ensure the flat is horizontal.






After milling the second pair, cut off from the parent stock.






Then after some tedious whittling with mill and bandsaw, tapped the mounting holes 6-32 and fit to the frames:






Still need to debur the threaded holes in the slots and shorten the screws.


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## kvom (Jul 20, 2014)

Started on the main bearings this afternoon using the same round bar of 660 bronze.  Interesting finding is that the bar measures 2.045" in diameter rather than the 2.125 + 1/32 promised on the Enco site.  Looks as if they pulled from the wrong shelf;  I sent them an email asking for a credit since the price difference is $26.

Anyway, the 2" bar is _just_ large enough to mill the bearings.  First task was to cut off two pieces about 2" long.  Glad the bandsaw could do it as a hacksaw would take a long time.






Then faced both sides on the lathe.






Mounted aluminum jaws on the vise on the CNC mill and cut a pocket to hold the work.  First op was to drill a 1/2" through hole.






Then spiral milled the hole to 11/16, milled the side profile, and the top boss, all with a 4-flute endmill.  Finally reamed to .75".






Then over to the Bridgeport to mill off the bottom to length, then back to the CNC mill to machine the other boss.






Still to do is mill slots on all 4 sides to fit the pedestals on the base.  The reamed hole is not a sliding fit for .75" drill rod, so I'll have to polish the rods for the crankshaft, or lap the holes, or both.


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## kvom (Jul 21, 2014)

Installed the main bearings to the base this afternoon.  The goal was to have a tight sliding fit with the shaft holes aligned, so lots of sneaking up on the dimensions and ensuring to take the same amount off the slots on either side, keeping the hole centered.  I was more than pleased that a test bar of drill rod slides easily into both holes at the same time.






At a future time I'll mill similar slots in the bottoms of the bearings to lower the crankshaft to align with the conrod and piston rod at dead center.


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## johnmcc69 (Jul 22, 2014)

It's coming along very nicely KVOM!

John


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## kvom (Jul 23, 2014)

Spent a couple of frustrating afternoons in the shop working on the cylinder bores.  The problem is that the bore is 4" long, and my longest endmill is capable of 2.5" maximum depth for spiral milling.  So I've tried to match it up milling from both ends, and it's ending up a couple of thou off where they meet.  The tried the boring head on the Bridgeport; got very bad finish on the first 1/2", plus the VFD shut down from overload -- normally should run this in backgear, but for some reason I can't get the back gear to engage.  Then looked to see about using the boring head on the CNC mill, and had clearance issues with both the vise and the table given the current setup.  All my efforts have been at a trial diameter of 1.75" vs. the final 2".

So this morning I logged in to McMaster and ordered a .75" 4-flute HSS EM with 4" flute length.  G-Wizard shows a deflection of only 1 tenth with axial and DOC engagements of .05", so I expect to get a pretty good milled bore that can be honed afterwards.  We shall see.

In the interim I'll start on the built-up crankshaft.


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## kvom (Jul 27, 2014)

Loaded up the big endmill and spiral drilled the cylinder bores to a nominal 2".  I discovered that the fore-aft faces of the cylinders are slightly out of square with the top and bottom, so I chucked it in the vise and used a DTI to set the bottom face parallel to the Z axis.  

As best as I can measure  the bores  about .004" smaller at the top with several thou taper towards the bottom.  Going to buy an adjustable cylinder hone and see what I can do with the taper.  For running on air a clearance of .002" in diameter for the pistons should work according to Dennis Howe.






Cut off more slugs from the 2" bronze rod and roughed out the pistons, then attached them to the piston rods I made earlier.  I'll use the rods in the lathe when turning the piston diameters to fit the bore; that way the rods and pistons will remain concentric.






Also started working on the cylinder packing glands but ran out of time to finish.


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## kvom (Jul 28, 2014)

Finished the piston packing gland this afternoon - quite simple parts from bearing bronze.  First ops were milling the spigot that goes into the cylinder cover, then facing to length and drilling/reaming the center hole.






Now hold the spigot in a square collet block and use the CNC mill to profile the flange and drill the mounting holes.






All done, shown with the piston and rods:






The valve packing gland is the same but a bit smaller, and the same process.


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## kvom (Jul 29, 2014)

Made a start on the crankshaft, which is held together with Loctite 620.  Used the gauge block to control spacing, and the surface plate to align.  I probably should have used another piece of rod for alignment.  Guess I'll see later if I need to press the pieces apart and reassemble.


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## kvom (Jul 30, 2014)

Continuing to build up the crankshaft.  Here's the setup to connect the two crank portions.  Calculated the gauge blocks needed so that the cranks are 3.125" apart center to center.






Afterwards checked for a fit and found that the total width of the cranks is a few thou too large to fit between the bearings.  So I'll have to sand/or file a bit once the crankshaft is complete.  In the meantime cut material to make the two ends of the shaft and got them to fit the bearings.  When I reamed the flywheels I got a sliding fit on 3/4 drill rod.  But the bearings and crank web holes were too tight, so I had to reduce the diameter with several grades of sandpaper on the lathe.  After fitting to the bearings I mounted the flywheels for a beauty pose.


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## kvom (Jul 31, 2014)

Cut the end pieces of the crankshaft to size and dry assembled as shown here:






Used a DI to measure deflection of the ends as I rotated it on the V blocks.  0 on one end and a max of 2.5 thou on the other.  Not too bad a difference over 14".  I haven't glued the end pieces yet as they need slots milled for the keys.  I'm going to wait until I get the keys in hand to see exactly how deep the slots should be.

Rented a cylinder hone to apply to the bores.  Still having a bit of difficulty getting accurate repeatable measurements of the bores with the equipment I have.  I want to mill the relief diameter at the rear end  in order to make it easier to determine how much taper, if any exists.  Might get an expanding reamer if need be.


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## kvom (Aug 4, 2014)

Some slow progress over the past two shop sessions.  Machined the outer radius of the cylinders for the back side plus drilled and tapped the mounting holes for the rear cylinder covers.  The small occlusion in the casting doesn't appear to be a problem as it doesn't extend into the part of the bore where the piston rides.  Then it was time to fit the rear covers.  

First task was to cut a 1/4" deep pocket .75" in diameter on the inside face.  This is needed since the piston rod extends a bit beyond the rear face of the piston.  Mounted the covers on the lathe and use a 1/2" center cutting endmill to go in .25", then expanded the diameter with a tiny boring bar,






I also needed to dismount and mount the covers several times to fit the inner boss to the cylinder bore.  Here's a technique I find useful in getting thin discs straight on the 6-jaw chuck.  Place parallels as shown and hold the work against them while tightening.  Then don't forget to remove the parallels before turning on the spindle.  FYI, this Cushman chuck is original to the lathe, both 1942 vintage.






The end result with the covers.  Need some nice 10-32 fasteners eventually.






The front covers will need some more precise work, so decided to drill and tap the holes for mounting the steam chest.  After using the surface plate to align the front faces of the parts and clamping them in place, I used a transfer punch to mark the cylinder block.   This was necessary since the holes in the steam chest bosses were centered on the bosses by eye, not a precise coordinates.






At the end of the day, put the cylinder assembly onto the base for a poser shot.


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## kvom (Aug 5, 2014)

Another fiddly day in the shop, working on the front cylinder covers.  Here I need to try to be more precise so that the holes in the cover and gland are as close to the center of the bore as possible.  First need to drill and tap the mounting holes for the covers.  Mounted on the CNC mill and finding the bore center.  Pretty much using the max Z space here.






I could then spot drill for the holes using a collet, but no room for a chuck. So back to the Bridgeport for drilling and tapping.  That spring loaded tap follower is a handy gadget.






Now back to the CNC mill for more center finding, then screwed a cover onto the cylinder.  Now I could mill the profile of the cover's flange to match the gland, and also mill the center pocket to match the flange.  Finally spot drilled the holes for securing the gland.






Finally, back to the BP to drill and tap the gland mounting holes.






Still to be done is drill and ream the .376" hole down the center of the cover, and hope it's in the center of the bore.  Afterwards I'll still need to turn the boss on the bottom to match the bore, plus reduce the outer diameter slightly sp that both covers can be mounted.

And then the same profess again on the other.  I've marked the cover and gland  so that I'll always use it on the same bore, in case there's some variation between the two sides.


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## kvom (Sep 4, 2014)

After 3 weeks away and 4 days of jet lag, I ventured back into the shop to do a little work.  Machined the top cavities on the cylinder block using the CNC mill.  This is the last major job on this casting other than trying to hone the bored straight and drilling the steam passages.






Before I left on the trip I turned one piston down to fit the smaller end of one bore, and found that there is too much of a gap at the wider end.  Loops like about 10 thou  vs. the 2 thou allowance recommended.  Won't try to turn another piston until I can get the taper out or else find that the extra gap won't cause enough blowby to matter running on air.


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## kvom (Sep 11, 2014)

A bit more progress this week.

- Got a friend to broach keyways in the flywheel bores, so was able to mount the crankshaft, bearings, and a flywheel on the base.  The gib key isn't very tight, so for the other side I'll reduce the slot depth on the shaft a bit.

- made the slide way tops, slides, and crossheads. Might have been a little lucky but the first piston rod lined up with the crosshead and screwed right in, allowing the crosshead and piston to slide pretty easily the full extant of the slideway.  Muncaster's version used a split bushing in the crosshead, but here a simpler bronze bearing will support the small end of the conrod.  Still have to machine the boss around the hold that connects the piston rod, plus drill an oiling hole in the top through the bearing.


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## kvom (Sep 15, 2014)

Spent a couple of hours at the CNC mill doing the first set of operations to carve the valve journals out of a piece of 3x7x.75" CRS:






I did get castings for these and got one machined, then messed up the second.  Got a replacement casting that had mismatched halves and wouldn't have looked enough like the first.  Hence, machining them from bar.  They won't be as thick as the castings so I'll need some spacers on the valve shafts.

Next will turn over to machine the opposite sides to match, then cut out of the matrix and finish on the Bridgeport.  Might let it run in the vibratory finisher for a while to get a matt finish.


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## kvom (Sep 16, 2014)

Reverse machined and freed from matrix.  Shown with the casting  version on the left:







The heights were slightly off, so used the setup on the BP to level:






Tested alignment on the engine base to find one of the mounting holes in the journal is slightly off center.  I will need to enlarge it later.  Still with three of the mounting screws tightened down a length of drill rod does turn.


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## kvom (Sep 17, 2014)

Made a start on the valve linkages.  Start with a 10" piece of .875" diameter 1144 stress-proof steel, and then turn a 1/2" diameter x 1/2" long boss in one end.  Make two of these.






Then make a square block of aluminum 1" thick and 1.725" on each side, with a 1/2" through hole in the center.  With 12" jaws mounted on the CNC milling vise, clamp the assembly together using a square collet block on one end.






Mill the top profile, then  rotate the block/bar/square 90 degrees in the vise to mill the side profile.  The face of the collet block is used to repeat the x0.0 value each time the assembly is turned.  Y0 is the centerline.






All for today:






Next session need to use the same assembly to drill the holes for the pins and machine the bosses, before cutting the rod free.  Hopefully can use the same technique on the conrods, although they are quite a bit larger.


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## kvom (Sep 20, 2014)

More ops on the valve links:

- Cut off the ends, then drilled and reamed the holes:






- With the 6" jaws back in the vise, the 3/8" rod can be used to find the hole's center in X






- machine the opening in the big end.






- Turn 90 degrees to round the ends






- Completed!






Same techniques with larger stock for the conrods.  Will be a tight fit even with the 12" vise jaws.


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## kvom (Sep 21, 2014)

Spent a few hours making the valve link pivot.  Started with a 2.75" length of 1.25" diameter steel rod that I faced on the lathe and drilled 1/4" holes 1" deep in each end.  Then clamped in the Bridgeport milling vise.






Then lots of cranking the dials milling most of it away in order to end up with this:






The drawings show a more complex shape, but since this part is screwed to the underside of the base casting where it cannot be seen, I used the Kiss principle.  The only necessity is that the radius rods pivot on the 1/4" rods attached to the sides with loctite.  The drawings also show a 1/16" hole drilled through the rods at their ends;  I presumed this is for a cotter pin to retain the radius rods, so I decided to turn grooves and use e-clips for this purpose.


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## kvom (Sep 24, 2014)

Started the radius rods by cutting the profiles through a piece of CRS after drilling and reaming the end holes .188.






The CAM program left three "tabs" on each rod to keep the parts from falling through.  The tabs were located on parts of the rods that won't be visible in operation.  Used the vertical bandsaw to extract the parts from the stock.  The pic shows the cut off tabs.  I would have been wiser to machine the sides and boss before the profile, as it appears there was some vibration affecting the cut quality.






After milling off the tabs on the Bridgeport, I turned the rods over to clean the scale off the back side in order to measure the thickness left.






I'll need a simple fixture next time out to finish.


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## kvom (Oct 1, 2014)

A bit more progress over the last week:

Radius rods show on the pivot plus the first ops on the upper and lower links - 






First op on the reversing lever - 






Next ops on the reversing lever - 






Now to machine the other side of the reversing lever a soft jaw pocket to hold it - 






Securely clamped - 






And third ops to finish - 






Finished reversing lever and upper valve links - 






I've decided it's time to start on the conrods, the longest pieces on the engine.  Stock is 1.75" diameter stress-proof steel and I need 11" exposed to the endmill to use the same type setus as for the slide valve links.  That means only 1/2" left to clamp on each end of the 12" vise jaws.  Next time out I'll do a setup and see how secure it seems.


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## kvom (Oct 5, 2014)

After preparing the stock for the conrods, I confirmed my suspicion that even the 12" vise jaws are too short to hold it the same was as for the valve link arms.  I need to buy some steel for a fixture, so in the meantime I started on the main bearings this afternoon.

Since 660 bearing bronze seems to be available only as round rods, I bought a foot of 1.5" diameter rod in  order to be able to mill the .75x1.25" cross section.  Only in hindsight did I realize that each half of a split bearing is .75x.675, so a smaller rod would have worked.  Duh.  Anyway, cut of 3" of the stock and faced each end on the lathe.






Then rough squared it using y-axis of the mill;  with soft metal this is the fastest as I can cut each side in one pass.






Scribed to saw in 4 pieces:






This is a technique I came up with to cut small pieces on the vertical bandsaw:






Further milling yielded these 4 pieces:






Then glued together using 3M high-strength adhesive.






I know it's common to soft solder bearing halves for boring the center hole, esp. using a 4-jaw lathe chuck, but I will drill and ream the .75" center hole on the mill.  With the halves clamped in the vise, the glue is mainly a means of keeping each set separate.  After the holes are done, I'll wait for the conrods to fit the bearings.


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## kvom (Oct 6, 2014)

Quick bit of CNC milling today.  Used some of the 1.5" bronze rod for the first ops on the valve packing glands, as shown here:






Then chucked in the lathe by the round 1/2" boss and turned to final thickness.  Results shown with the split bushings; here I interpolated the holes on the CNC mill and reamed .75".






I was planning to drill the holes for the valve rods _in situ_ after attaching to the steam chest, but that's probably overkill.


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## kvom (Oct 14, 2014)

Instead of actually cutting metal, the past two days have been spent in learning basic Solidworks, since I was able to get a free student edition version as a US veteran.

Here's my first cut at modeling parts and an assembly of the conrod, bearing, and the two valve links:


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## kvom (Oct 17, 2014)

Finally got to cutting metal on the first conrod, using the same method for holding the round stock as for the valve link rods.  "Fixture" starts as a length of 1/4" HRS to which I bolted a pair of parallels to one edge.  The collet block and its partner are held against the parallels with "Mighty-Bite" clamps, and both ends then clamped vertically.  Here's the workpiece on the fixture after the first ops:






Rotate the setup 90 degrees and reclamp, then further ops:






Finally flip 180 to do the details on the inverse side.






The surface finish isn't as nice as I'd hoped coming off the mill, so some hand work will be needed after the rest of the milling.


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## kvom (Nov 1, 2014)

The conrods have been a "struggle" given the size of the parts, their odd size, and the number of ops needed.  Here's a week's worth of effort.

After machine the four profiles, I machines some soft jaws to hold the shaft:






Then I could do the machining ops on each end.











Only a few ops to go:






On the first one I made a mistake, programming the bottom profile as a .375 endmill but using a .5" endmill.  The result is still functional but is not symmetric.  Given the amount of work to get this far I'm going to finish it, reserving the option to remake in the future.  I've learned enough making these two that the third would take considerably less time, though still not trivial.


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## kvom (Nov 4, 2014)

Some slow progress the past two days:  yesterday finished the machining ops on both conrods, and today fitted one of the split bearings to its rod.






The bearing machining was manual and was lots of "whittling" away at the bronze until it fit.  I measured the thickness of the big end and calculated the offsets from center to cut the top and bottom slots.  Using a 3/8" endmill with an estimate of +/- .110", I found that I got a nice sliding fit at +/- .114", so all the rest of the slots were cut at that width.  First task was to cut the top and bottom slots to depth equally so that the bearing could enter the conrod opening.  Then I split the bearing halves and did the front and back slots individually.  The far end slot is cut at a 5-degree angle from vertical to allow the tapered keeper to widge the bearing against the crank.

As assembled initially, it's very stiff to turn.  I need to relieve the main bearing.  It appears that the conrod is slightly off from being straight front to back, as the big end is off center in the crank opening.  This could either be warpage in machining, or else having the holes for the crosshead pin being slightly off from perpendicular.  However, there's enough flex in the rod to allow it to be assembled to the bearing and crank as shown in the picture.

I still need to drill 1/16" holes for oiling.


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## kvom (Nov 25, 2014)

Got back to the engine a bit this afternoon by machining the end journals of the crankshaft (slots for the gib keys) and then loctiting them to the rest of the crank.  I also turned the conrod upside down, which made it line up much better.  Using the flywheels to turn the crank, the entire drive of crankshaft, conrod, crosshead, and piston operate quite smoothly for a first cut without lubrication.


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## kvom (Nov 27, 2014)

Some minor testing today.  I drilled and tapped (1/4 NPT) air supply hole in the center of the rear face of the steam chest and did the same to the bottom of the exhaust hole in the cylinder block.  I then bolted up the steam chest, its cover, and the cylinder block and applied air pressure.  If all the ground surfaces were perfect then there should have been no leaks.  But the interface between the cylinder and steam chest was by no means air tight.  Therefore it appears gasketing will be needed.

Eventually the valve plate (ground on both sides) will be situated between the chest and cylinder.  The fastening of the plate, as it currently sits, is just 3 through holes on each side.  The drawing of the valve plate shows 4 additional through holes, two each along the front and back edges.  However there are no matching holes shown on the drawings for either the chest or cylinder.  Muncaster shows the 4 extra holes tapped into the cylinder.  Simon extended  4 of the cover bolts for this purpose, but I think I'll plan to to just mill counterbores into the bottom surface of the chest to clear the screw heads.

It is more important that there be no leaks anywhere between the valve plate and the cylinder.  I'll probably need to use a silicone gasket of some sort.  The plate and steam chest interface is easier to seal and a paper gasket should work.  I'll need to remake the valve plate as I messed up the first try.


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## kvom (Dec 2, 2014)

Couple of little parts squeezed into some shop time.  These are the "keepers" that wedge the split bearings together in the conrods.  One side is angled 5 degrees to match the rear face of the bearing.  The 10-32 screw causes it to rise until it presses the bearing.


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## kvom (Dec 6, 2014)

Machined the second split bearing to fit the second conrod and assembled both rods between the crossheads and crankshaft.  Turns by hand fairly easily and should wear in with use.  I'll relieve the main bearings a bit when next disassembled.


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## kvom (Dec 10, 2014)

Lots of little steps over a couple of afternoons to show, making the valve guides and valve packing glands.  First, slice off about 4" from a 1.5" hex brass bar.






Skim just enough to make it 1.5" round bar:






Turn a 1/2" diameter spigot, then drill and ream 3/8" diameter .75" deep.  Then repeat on the other end of the bar:






Then part off:






Turn some bearing bronze to 3/8" diameter and loctite into the spigots:






Next drill and ream a 1/2" hole in the round bar:






Now turn some bearing bronze to 1/2" diameter and drill/ream a 3/16" hole 1" deep, then part off and make one more:






Round the closed end of the bronze pieces using a corner rounding bit as a form tool.  The bit has a flat that allows the boring bar holder to assure that the cutting edges are horizontal.






Face and part two discs from the 2" bar and loctite the bronze piece onto the disks.  Let cure overnight.






Drill and ream the bronze inserts in the packing glands to 3/16 and face the gland disks (not shown).  Then for each of the 4 pieces use the square collet block to drill clearance holes for 6-32 mounting screws:






Then move the collet block to the CNC mill to form the lozenge shape:






Finished parts:


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## kvom (Dec 11, 2014)

Today I started drilling the holes on the front and back of the steam chest.  Using the DRO on the "back" side, I located, drilled, and reamed 3/8" holes.  These will eventually be enlarged to 1/2"+ for the valve guides, but I wanted to see how far off I might be in locating the rod side.  On the rod side I drilled and reamed 1/4" holes.






When I fit the valve rods through the front it appeared that the rear holes were "off" by an eyeball measurement of .05" or so.  Whether this was because the holes were off or the rods aren't straight was hard to tell.  Nevertheless, I figured to correct any misalignment via the rear, so I proceeded to counterbore the front using a .5" endmill followed by a .501" reamer.






Now, because there is less material around the .25" hole, it's possible to align the rods using the wiggle room provide.  But when I then try to install the valve glands everything gets tight again.  Clearly all three bores are not aligned to tenths.

So here's where it sits as of today:






My thoughts now is to widen both front and back bores to .551" via a 14mm reamer, giving room to adjust both the guides and glands into line.  But if anyone has a better idea between now and Monday please let me have your thoughts.


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## kvom (Dec 16, 2014)

After boring and reaming the holes for the valve guides in the steam chest, I am able to have the valve rods go from the packing gland to the guides.  However, they only slide easiy when rotated to a favored position.  Evidently the rods are not perfectly straight, which is not that surprising  for 1/4" bar that's 4" long.  I still need to fabricate and attach the rod ends, and will attempt to position them in the favored orientation, but otherwise I'll consider opening up the valve guide diameter and/or reducing the diameter of the end of the rod that slides in the guides.

Another task I undertook was finally attaching the two rocker slide frames with sections of drill rod, loctited (620) into place.  The rod that holds the reversing lever has a flat milled in the bottom to accommodate a 5-40 set screw.  Here's the test assembly:






The engine has a number of pins, threaded on each end similar to studs, for assembling various components.  I decided to tackle the two that connect the conrods to the crossheads, using thread milling.  Since I'll do all the studs in the same general way, this was a test.  The pieces in question are 3/8" drill rod threaded 16 TPI.  Some years ago I bought the spindle nose from a Monarch 10EE (same as my lathe) that was being parted out.  The spindle is a D1-3 and was mounted on a round piece of ground steel.  So I can mount my Sjogren 5C collet check, and clamp the entire assembly in the CNC mill vise.  After centering, I can thread mill any size rod for which I have a 5C collet and which is up to about 8" long.  For "production" use, the workpiece can be positioned quickly:  with the threadmill at X0Y0Z0, raise the rod in the collet to touch the bottom of the tool, then tighten the check and press the start button.






And proof that it works:






It takes a few tried in the CAM program to get the minor diameter of the thread and the diameter of the threadmill matched up to allow a nut to screw on, but once set the CNC programs can be reused many times over.  I'm doing 3 passes for the 3/8" drill rod and 2 passes for 1/4", followed by a spring pass at final depth.  The spring pass does seem to be a necessity.

After making the two 3/8" pins, I did the programming and test for 1/4", since I'll need a good number of studs of this size.  Here's my little sample:






One advantage of threading this way is that there's no burr at the end of the thread.


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## kvom (Dec 20, 2014)

More thread milling today, this time 10-32 threads on 3/16 drill rod.  The plans call for 8-32, but I can see no reason for the smaller threads since these are the pins for connecting all the valve linkages.  Once the programming is done then the threading is a no-brainer.  The thread mill is a tiny little thing.  Here are the pins showing where they go:






The pin connecting the lower valve link and the conrods is specified as a press fit, since both ends need to clear the upper valve link.  I think this will make disassembling difficult, so my plan is to make the cross holes in the lower links suitable for a threaded connector.  On side is the 3/16 clearance hole and the other side tapped 10-32.  Then I'll mill a slot for a screwdriver in one end of the pin and shorten it so that it's flush on both sides.

After making the pins, I did a bit of fettling to mate the upper links and the linkage rods:






Now I need to replenish my supply of 10-32 nuts.


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## kvom (Dec 21, 2014)

Spent a number of hours in the shop working on the lower valve links.  I still need to do the side profile on these, but here they are with the rest of the valve linkage pinned together:


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## kvom (Dec 22, 2014)

Finished profiling the lower valve links today:






Then made an attempt to machine the "sliders", analogous to die blocks in other valve systems.  Although I used a negative roughing clearance that appeared to make them fit the rocker slides, they are a few thou too tight.  I'll see if I can file/sand  the outer radius enough to have them fit and slide smoothly, it may be easier just to start them over.


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## kvom (Dec 23, 2014)

Since the engine, even in a partially assembled state, is getting too heavy to lift easiy, I decided it would be a good idea to strip it down to the base, and drill and tap the side hole for the lower reverser mount.  At the same time I could attach the bracket that supports the radius arms to the inside of the base casting.


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## kvom (Dec 27, 2014)

Finished my Solidworks model of the engine, not to generate any drawings or CAM files but mainly as a learning tool for SW.  I skipped several parts not needed to check the motion.


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## kvom (Jan 1, 2015)

I had to remake the lower valve links for a 3rd time, having misread the plans the second time.  Rather than my original plan of a threaded pin to attach to the conrod, I went with a press fit.  One side of the hole was reamed .189 and the other .187 (I have a set of over/under reamers) so that the pins were pressed in one side only via vise jaws.  The pins were made to match the width of the links (.625") rather than .937 as on the drawing;  seems an error on the plan since the upper links need to pivot over the lowers.  Here are the upper/lower/conrods shown in place.






I need to shorten the mounting screws for the slider guides, and then I should be able to see the complete valve motion.


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## kvom (Jan 3, 2015)

After shortening the mounting screws for the slider guides and making the pins to connect the sliders and the upper valve link, it was time to see how the mechanism would work.  The first issue came up right away as it was obvious that one of the upper links was leaning to one side.  Found out that the lower pin that joins to the lower link was drilled at an angle, so that link will need to be remade.

The other link was connected to the sliders:






I found that they would slide well on the forward part of the conrod stroke (toward the cylinder), but not on the reverse.  Closer examination shows the sliders contacting the "shoulder" of the link:






The position of that shoulder is not dimensioned on the drawing, and I had made a guess., apparently wrong.  My plan is to whittle it down until the sliders clear, then make two new links with the measured distance.


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## kvom (Jan 4, 2015)

Slight progress today.  Made a rough version of the reversing screw along with its brackets as can be see in this view:






Being able to lock the slides at a fixed angle frees up a hand or adjusting the rest of the mechanism.  I discovered that if the assembly tilts too far forward then the slides will come out of the guides.  The position shown allows the center of the slides to just reach the end of the guides as is as far forward as should be allowed.  Since there is more thread below the lever it seems a stop should be installed.  Until I have valves and the rest of the mechanism assembled, I'll not know how far the the maximum would be in either forward or reverse.

The slides shouldn't hit the upper link.  I did move the shoulders 1/3" lower, but then realized that I hadn't installed spacers between the link and the sliders on either side.  These keep the sliders apart and inside the grooves of the guides.  This picture shows where these spacers (about 1/8" thick in this case) should go:






I also discovered that the space between the guides is about .020" too narrow (the other side is better).  While it doesn't inhibit the mechanism is means that the pin that will connect the upper link to the valve link rod will be too wide as currently made.  Machining the frame is impractical at the point, so I may just to a combination of narrowing the sliders on this side as well as the taking a bit off the top of the valve link,  I may also try to make the pins a bit shorter and use thinner nuts.


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## kvom (Jan 7, 2015)

Spent the last two shop sessions making the slide valves.  The plans call for either bronze or CI, and since I had a suitable chunk of 2.5" diameter Durabar from a previous project, that was the choice.  After cutting it in two, facing both ends on the lathe, and milling the sides, I ended up with two 2" square chunks.  Second session I machines the sides down to the target dimensions of 1.6x1.5", one .82" thick, the other .86.  In reality the overall dimensions are not critical.






More swarf than workpiece at this point.






I then used the surface grinder to grind the bottom face that will slide on the valve plate, and then machined the exhaust pocket into the ground surface.  Pocket depth is .188" using a 1/8" 4-flute carbide EM.  An advantage of CI is that there is no burr and edges remain sharp, which is a goal with these valves.






Then back to the Bridgeport to finish the top portion.






Photo of the cross slots was unfocused, so I'll show that on the next post.


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## kvom (Jan 8, 2015)

Spent some time making the 2 anchor nuts that connect the valves to the valve rods.   Simple 1/2x1/2x1/4 steel with a 1/4-28 hole through the center.  Main fiddling was milling the thickness to have a snug sliding fit in the slots.






Still need to experiment on the best way to add the crosspiece to the end of the rods.


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## kvom (Jan 23, 2015)

After receiving a shipment of model scale nuts from AME in Fl, I discovered the 10-32 nuts wouldn't screw onto the pins I made for the valve linkage,  Seems the nuts I used for testing the thread milling code were loose threads.  So I did the mill setup to cut deeper threads.  With the setup for thread milling, and having enough 1/4" drill rod, I spent a number of hours working on studs.  I need 12 for the steam chest cover, 6 for the steam chest, and 6 for the cylinder.

Today I received a box of steel flat washers so I could try on most for size.  While the cover studs are no problem, I find that there is not enough space in the cylinder sides for a complete washer, and I will have to cut a flat side in them to fit.  The studs for the steam chest to cylinder are  about 1.5" long, and with all of them screwed into the cylinder I can't lower the chest cleanly onto them.  Since I can attach the chest with screws, it seems to be a matter of a close fit in the holes drilled in the chest.  I probably need to enlarge the clearance holes slightly.

Here's a test assembly of where I've gotten to so far:






I need to make a goodly number of 10-32 studs for the cylinder covers, reversing stands, and crosshead guide plates, so I need to order more 3/16 drill rod for those.


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## kvom (Jan 28, 2015)

Last few hours in the shop were spent making more studs: 10-32 for cylinder covers and crosshead guide bars until I ran out of stock, then 5/16-18 for the base.

I ordered some more drill rod from Enco, along with some 1/8" thick ground steel sheet for the valve plate.  I had twice tried to grind the valve plate myself starting with 3/16 HRS. but each time the material warped.  The smallest sheet that works is 5x24", so enough for 3 of these.

Should get delivery tomorrow afternoon.


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## kvom (Jan 29, 2015)

The method I had tried to attach the end boss to the valve rods using loctite was not successful.  I was able to pull it off the end of the rod with only moderate hand pressure.  I was reluctant to use SS for fear of warping the thin rods, so came up with this idea:






The rod ends are threaded 1/4-28, while the boss is drilled and tapped the same.  After applying high strength thread locker and curing overnight, I then secure the rod end in a 5C square collet block and mill the boss to width.  Finally the boss is reamed.  The cross pin helps secure the boss from turning since the end of rod has been reamed to the same radius.  The photo shows my test piece secured in the end of the valve link.

So today I made two of the bosses:






And have them attached and curing to the rods awaiting finishing the next shop session.






Also made the studs for mounting to the sub-base, eventually.  For now made some "feet" that raise the base above the bottom of the flywheel.  These make moving the engine around the workbench easier.











Got the UPS delivery today with materials for finishing more studs, plus the valve plate.


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## kvom (Jan 30, 2015)

Back in the shop aiming to finish the valve rods.  I insert the rod into the 5C collet block and use a height gauge on the surface plate to align  it.  The over to the mill to bring the boss to the desired thickness (.370").  By taking small passes and turning the block over, the rod remains centered on the boss.






Fitted to the valve link rod:


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## kvom (Feb 3, 2015)

Did a first test assembly of one half of the engine with all the moving parts other than the piston and valve in place.  Turning the flywheel gives gives a quite smooth action throughout the full cycle, which is encouraging.  As well, the tilt of the reversing mechanism doesn't move during the action even if it's not locked.  Also a good sign:






I discovered some dimension errors in the drawings making the upper valve link too wide to pass between the bronze slide guides, so some trimming was necessary to give clearance.  The same is true of the pin that connects the valve link rod to the upper link, since it too must clear the guides.  I'm using two thin nuts on each end of the pin.


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## kvom (Feb 7, 2015)

Last time in the shop I tweaked the valve plate into its final dimensions, so now it remains to mill the ports.

Then as a sideline I decided to try to make some model scale 10-32 washers starting with US standard size washers.  I need to turn the stock washer diameter down from .5" to .375", and I'll need about 50 of these.  So I came up with this, made from 1/2" rod:






The washers fit over the right hand piece, which is then inserted into the left to clamp the washers.  Left hand piece is held in the lathe check with the right held in a live center.

Works sort of OK, but it's hard to get enough clamping pressure to allow a full depth cut.  Worked best taking .02" per pass with a fast feed.  Did about 10 washers at a time.

The 10-32 model scale nuts from American Model Engineering take a 9/32 wrench.  This size wrench is not part of standard imperial wrench sets, so I found and ordered one on eBay.


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## kvom (Feb 8, 2015)

Spent most of the day remaking one of the upper valve links.  Quite a number of setups both CNC and manual:






The drawing for this part is missing some dimensions, among which is the position of the "shoulder".  This needs to clear the sliders as can be seen here:






The prior piece would have interfered ( but that's not the reason for the redo;  I drilled one of the cross holes out of parallel).


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## kvom (Feb 10, 2015)

I assembled the remaining side of the valve system after a small amount of fettling in order to get free range of motion:






I discovered one potential dimension problem.  While the valve rod is shown as being 5.665" long and mine are 5.75", the ends of the rods still come out of the guides but approximately 1/8".  Since the steam chest wall is nominally .75" thick and only 1/2" of the guide is inside the wall, I think I'll just make the guides 1/4" longer.

The valve rods have a total travel of very close to 1" with the current inclination of the slides.  Next task will be to install the valves themselves onto the rods.


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## kvom (Feb 12, 2015)

Decided to install a valve on one side and see how the valve motion adjustment can work.  It takes a bit of agility to drop the steam chest over the studs and land the valve "nut" into the slot on the valve.  Once that was accomplished I adjusted the travel by turning the valve rod until I got a good approximation of balance travel between the two steam ports.






When I tried it with the other side the warp in the valve rod caused all sorts of problems, so I decided to remake it.  While the plans call for 2.3" of 1/4-28 thread, that's more than is needed, since I made the valve differently.  Sp after measuring where the nut was on the good rod:






I decided to make the new one with 1.5" of thread, but even this amount has a great deal of leeway.






The new one is straight, so avoids many problems that were caused by the warped one.


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## kvom (Feb 13, 2015)

Installed the conrod bearing "keepers".  These are small wedges that are tightened by a 10-32 screw that passes through them vertically.  Stock screws didn't have enough thread length, so I used some 10-32 threaded rod from Enco.  Plans call for a 3-degree (actually .05" taper per inch) but apparently I tapered the edge of the bearing 5 degrees, so made the wedge to match. Photo appears that I mounted it sideways.






When finished there will be a steel block on the end of the conrods held by tension of the threaded rod by nuts on each end to tighten the end.  Not standard practice by any means.

Also finished the studs for the rear cylinder covers.  7 studs in one session is all I have patience for.


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## kvom (Feb 16, 2015)

I found some SS 10-32 washers at Ace hardware that will work as well or better than the ones I bashed out earlier.  And they are .02" thick, about half that of the others.






Then today I finally got a complete assembly with all moving parts save the pistons and one flywheel:
















With the valve in place I did a dry run of timing the engine.  First set the reversing mechanism so that the slides are vertical.  Then position the valves, by turning the valve rods, so that neither steam port is exposed when the flywheel is turned.  The valves still move.  Then I gradually turn the reversing shaft to tilt the slides so that the top moves towards the cylinder.  After a few degrees I turn the flywheel to see if either steam port is exposed.  Then I adjust the valve via its rods until both steam ports are opened the same amount by one turn of the flywheel.  

It doesn't take much inclination of the slides to have both ports open fully, and further inclination increases the valve travel further.  I probably need stops of some sort on the threaded shaft to prevent too much travel else the valve rod will hit the guide.  With this inclination the flywheels will turn clockwise when views from the side of the reversing gear.

I made an error in the positioning of the reversing lever, making it perpendicular to the slides rather than at a lower angle.  As it sits now I don't have enough thread on the reversing shaft to incline the slide backwards to get reverse.  Since the reversing shaft isn't fixed, I can just replace the threaded rod portion with a longer piece for now.


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## kvom (Feb 23, 2015)

After hearing that the .012" cylinder taper wasn't going to cut it I spent the afternoon playing with this impressive combination:







Expanding 2" reamer with a MT3 shank hooked to a MT3/R8 adapter for the Bridgeport.  Don't try this on your mini-mill.  Found the reamer on eBay some time ago and got the adapter from Shars.

The cylinder didn't like heavy cuts with this, and I probably adjusted  it 10 times before I got it done.  The bore surface is only mediocre, but I'll run a cylinder hone through it later on.  At least bore mic measures the same at both ends.

I did just one bore, so I'll have the same process to do for the other.


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## kvom (Feb 25, 2015)

Spent today to work on the last unfinished casting, the cylinder cover that I had rough machined long ago.  I mounted the cylinder in the CNC mill and located the center of the bore, the attached the cover with screws.  Milled the profile and the pocket for the gland, plus spot drilled the positions for the gland mounting holes and the piston rod.






Then over to the Bridgeport for drilling and tapping.  Test fit of the gland:






Then some fettling on the assembly with the piston rods in order to get the rods to move smoothly.  Tightening the gland screws unevenly can cause binding on the rods.






The bases of the two covers are slightly different thickness, so I'll plan to face off the thicker one in the future.

After I use the big reamer on the other bore and remake both pistons, all the parts needed for the engine to run will be able to be assembled.  I ordered some teflon film to try out as gasket material. Before trying to run it I want to try to eliminate as much friction as possible.  The conrod bearing are a too tight to the crankshaft webs, and I need to drill oil holes for them as well as for the main bearings and possibly the crosshead.  The lower valve links will be thinned as they're a bit too close to the uppers.


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## kvom (Feb 26, 2015)

Another afternoon of fettling.  I took about .02" off the flanges of both the conrod and main bearings to reduce friction, and then drilled oil holes for those bearings plus the crossheads.  The conrod big ends required a bit of thinking to get a secure mount for drilling, but I eventually came up with this:






For the big ends and crosshead, the plans call for a .062" hole, while the hole for the much larger main bearings is not dimensioned.  I did drill these the same, but it would be fairly easy to increase the diameter when needed.  In any case, I intend to add oil cups to all 6 such oiling points, and these will require further drilling and tapping once I know the thread size.

I know there are many here who make their own cups, but the prices for ones from PMR and AME are so inexpensive it doesn't make sense to me to make them.  I'll decide at Camin Fever which way to go, and in the meantime just squirt oil down the holes directly.

I did find that one of the wedges for the conrod bearing is too small to press the bearing halves closed.  Not sure whether to shim it or make a new one, but in any case I ran out of time to drill the second conrod.  With the one conrod reinstalled with the crankshaft and main bearings, there's considerably less friction turning it than before.

One thing to keep in mind is that when drilling through bearing caps and then into the bearing is to mark the caps.  That way they will be replaced in the correct orientation if they need to be removed.


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## kvom (Feb 28, 2015)

Reamed the other cylinder bore with the expandable reamer and also faced down the oversize cylinder cover.  Also cut off two more slices of the 3" 6061 round, which I'll turn into new pistons to fit the bores.

My gasket material is held up at UPS because of this week's bad weather, but when they arrive and I've made the pistons, it will be time to assemble and put some air to it.


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## kvom (Mar 6, 2015)

And we have a runner!

For at least 2 minutes anyway.

Having gotten delivery of a 1' square piece of .020" PTFE, I devised a way to clamp it flat on some aluminum and cut gaskets using a very sharp-pointed 60 degree carbide chamfer bit on the CNC mill.  Tow for the valve guides:






And four for the cylinder covers:






Buttoned everything up after some additional fettling:






And applied some compressed air.  The engine was still a bit stiff so gave the flywheel a bit of assistance and it struggled to life.  With high pressure it continued to run faster than I would have liked, but cutting down the air caused it to stop.  I figured it just needed some run-in time, plus there was no sealant on either side of the valve plate where air was leaking as well as the steam chest cover.

I was just about to stop and set up for a video when the engine jammed up tight.  Couldn't turn one flywheel at all, and the other turned slightly because the crankshaft had worked loose on the center bar:






I had been relying on Loctite to keep things aligned, but apparently there's enough force at work to loosen the seal when things won't move.  Started disassembly to find that one of the piston rods was stuck tight.  After a more complete disassembly I found evidence of rubbing on one side of the aluminum piston and some scoring on one side of the piston rod.  I checked the rod against the surface plate and it's not bent.

Seems the jam occurred between the rod and the bronze gland at the position nearest the crank.    I believe the bore is just very slightly off from the cylinder head, so the rod was rubbing on the head, and the crosshead seems to be rubbing on one side of its guides.

So after repairing the crank, I'll make a new rod and try to relieve any rubbing between it, the cover, and the gland.  Before another run, I'll also make some gaskets for the steam chest.


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## kvom (Mar 9, 2015)

I ordered another stick of 3/4" drill rod to finish rebuilding the crankshaft, so while waiting for it to arrive I made my version of the reversing hand wheel:






Eventually there will be an acorn nut in the center, and the handle could use a bit of a taper for esthetics.


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## kvom (Mar 21, 2015)

So now it's running 'OK', although noisy with the high air pressure needed.  It will need some fettling and running in to work on lower pressures and speed.

[ame]https://www.youtube.com/watch?v=eY7jhkFV3Do&feature=youtu.be[/ame]

There's a sticky spot when the #2 piston (further from reversing wheel) is fully back towards the crank.  That's why it failed to self-start in the video.  Quite airtight with gaskets in place.  I used RTV between the valve plate and cylinder block, and teflon film elsewhere.

The engine will be in Maury's booth at Cabin Fever if anyone wants to see it in person.  I will probably not do a major disassembly between now and the show, but will try to locate the sticky spot.    For the previous problem I ended up taking about .030" off the base of the #1 crosshead and the same off the matching crosshead bar, allowing the crosshead to move outward that amount to align the piston rod better.

I still need to machine keepers for the ends of the conrods and replace a number of screws with studs and nuts.

The reversing lever was installed horizontally with the slides vertical, but that prevents it from being able to tilt back enough to reverse the engine.  To fix that I'll need to pin the lever more upward facing at neutral.  I may try using a longer piece of threaded rod in the meantime; will look awkward, but possibly can work.

After the shows it will be time to install oil cups, paint, and build a better base.


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## Cogsy (Mar 21, 2015)

That is an impressive engine! I'm not much of a steam guy (although I do plan to build at least 1 someday) but this is an excellent model. Sounds like it's ready to do real work too.

Congrats on getting it running.


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## kvom (Mar 22, 2015)

Bit more shop time this morning on the engine.  By disconnecting the conrod from the  #2 crosshead, I determined that the crosshead and/or piston was the cause of the sticky part of the motion.  An examination of the piston showed some scrape marks on the crank end, so first action was to file and polish a bit on that portion.  Then I noticed that with the piston rod attached there was some binding on the side of one top bar, so I took about .015" off both the crosshead base and the bar.  Finally, I noticed that the crosshead base was protruding slight above the engine base, meaning that the crosshead would rub against the bottom of the bars.  I decided to shim the  bars up by using washers around the mounting holes.  The washers measure .017 thick, and doing so freed up the motion quite a bit.  After reassembly I made a second video.

Self-start still requires quite a bit of pressure, but once in motion I can throttle down quite a bit.

[ame]https://www.youtube.com/watch?v=VYa-qSQ28dE&feature=youtu.be[/ame]

Seems to be running about 60 rpm.  Any slower it eventually stops.


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## kvom (Apr 2, 2015)

Spent the last two shop sessions making studs to replace the screws of the main cylinder heads and the crosshead guide bars.  As before, studs are made with 3/16" diameter drill rod with 10-32x1/4" threads on either end.  Only a few socket-head screws left to replace after Cabin Fever.


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## kvom (May 7, 2015)

After touring the engine to both Cabin Fever and NAMES, and with a week or so to get back into the shop, I started on some of the unfinished tasks.

First was to machine a "keeper" block that seals off the end of the conrod.  It's just a steel block with a groove to clear the wedge, but needs a tight fit to the rod.  Hence a fair amount of fettling.  Then I removed the #1 conrod to drill and tap for an oil cup I bought at CF.






With the rod removed, I found that the sticky spot in the motion is definitely in the #1 side and seemed to be coming from the crosshead guide bars.  Since I had an oil cup to install on the crosshead, I did some relieving on the bars as well.  Then put it all back together and fired up again on air.  It still needs about 40 psi to self start but afterwards it will run nicely at 20.  Below that it grinds to a halt.






Side 1 took most of the day, so I expect the same the next time for side 2.  I have larger drip oilers for the main bearings but no tap (1/4-40) at present.  I could have bought the tap for $10 at CF but cheaped out.  I can thread mill the holes but that sounds like a lot of work vs. 10 bucks.


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## kvom (May 21, 2015)

I've been playing with getting the 4th axis set up on the mill, as well as family matters, but today decided to do a bit on the engine.  Goal today was to make the studs that connect the conrods to the crosshead.  I had made one earlier but mis-measured so that it was too long, and for the other I'd just used a 3/8" bolt and nut at CF.

After measuring properly, I decided to use the 4th axis horizontally to hold the stock for thread milling each end:






Installed on the engine:






Other than cosmetics, the main task remaining is to orient the reversing arm so that there's enough travel to actually make the engine reverse.  To maintain the arm on its shaft at the correct angle, I'm going to broach a key slot in the arm using the small broach I bought at the CF auction.  The broach is 1/8" wide but the cutting teeth are only 1/16", so that will be the width of the slot.  I don't have a bushing for the broach and could have made one, must found a 3/8" bushing on Enco for less than $10.  When it arrives next week I'll have to see what shims I'll need with it.


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## kvom (May 29, 2015)

After some analysis using my SolidWorks model of the engine, I decided that I could modify the geometry of the reversing mechanism by a modest extensions of the threaded shaft to enable the engine to run in reverse.  To validate this, I replaced the existing shaft and handwheel with a long piece of threaded rod and moved the mechanism to approximately the same ange backwards as for the forward speed.  With this setup I applied air, and the engine ran very well.






Then it was a simple matter to mark the rod for enough room to add the handwheel and its jam nut.

The remaining tasks for the day were to drill and tap the main bearing caps (1/4-40 thread), and mount the PMR drip oilers I bought at Cabin Fever.  In addition I whittled down a piece of CRS to make the keeper for the end of the #2 conrod.






All the rest of the work needed to mark this complete can be done with the engine completely disassembled and ready for paint.


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## gbritnell (May 29, 2015)

Really some great engineering on the engine!
gbritnell


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## kvom (May 30, 2015)

Thanks George.  It has been a fun project so far.


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## kvom (Jun 15, 2015)

I've been away from home for a while, but now back at it.  I disassembled the engine in prep for paint, and while considering options there I made a start on getting my base ready to attach.  The base itself it a piece of black walnut 1.7" thick that I had made by a furniture maker near York while I was at Cabin Fever.  I positioned the engine base as accurately as I could and used a transfer punch to mark the holes.  After drilling the wood, I decided to still use the aluminum feet underneath, since without them it's difficult to get a grip to lift it.  I cut some 5/16" drill rod to length for the studs, but I will wait to mill the threads when the current setup on the mill is broken down.






Today, I started filing the join lines on the flywheel spokes and the main bearing caps preparatory to paint.


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## kvom (Jun 23, 2015)

Got the mill setup to make the studs for attaching the engine to its base.  The view from the bottom:






And from the top:


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## kvom (Jul 28, 2015)

Masked the castings and sprayed primer on the parts to be painted.  I had decided to use an automotive epoxy paint hence gray epoxy primer.  The paint is copper colored with a very small metal flake accent.  Not exactly 19th century, but the Victorians did like bling paint jobs on their engines.

Still deciding whether to paint the flywheel spokes the same color or something different.


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## kvom (Jul 30, 2015)

Pics of parts after masking and priming:











Setup for the air brush, using CO2 as propellant.  No chance of water getting into the paint.  The regulator is set for 30 PSI.






Here's the paint system I'm using.  Enough for many models:






First I did the smaller parts.  Having them on the stand makes spraying all over easier.






Did two coats 15 minutes apart.  I plan a 3rd coat tomorrow, plus do the other side of the cylinder.  Then attack the base later.  This amount of parts used two oz. of paint and a half oz. each of the activator and thinner.


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## RonGinger (Jul 30, 2015)

Read the label carefully- I once painted a model with  rustoleum. It had a nice finish, but I decided one more coat might be good. That turned the whole thing into wrinkle finish. And it was hard as a bear to sand. I never did get as good a finish.

the label warns to recoat within 24 hours or wait 7 days before recoat. Should have read that first.


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## kvom (Aug 2, 2015)

Painted the base yesterday, and started reassembly this afternoon.  The paint job turned out OK in the end; not professional but decent from a couple of feet away.  The paint is fairly thin and tended to run a bit down vertical surfaces so being slightly darker on crevices where it pooled.  Here's where I stopped mid-afternoon.







I need to shim the cylinder and crosshead bars in order to get the crank and piston moving smoothly before putting the valve gear and reversing mechanism in place.


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## kvom (Aug 3, 2015)

Back at it today, and finished the reassembly.






Did a quick run without oiling it up to test ooeration.

[ame]https://www.youtube.com/watch?v=UFTlSnMvJyI[/ame]

A little squeaky, but since I probably won't run it for a while I decided not to lube it and have oiled up and collecting dust.

I've decided for now to leave the flywheels unpainted, and declare this engine "finished".  Might change my mind later.

Thinking I'll get back to the Westbury paddle engine now that Herbie is also working it.


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## bouch (Aug 5, 2015)

kvom said:


> Did a quick run without oiling it up to test ooeration.
> 
> https://www.youtube.com/watch?v=UFTlSnMvJyI



Congratulations on a nice looking engine!

Bit surprised that you have it running "under".  Most engines I've seen usually run "over..."


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## kvom (Aug 11, 2016)

As a result of my goal to turn a multi-start thread, once having succeeded on a short piece of brass, I decided to remake the reversing shaft on this engine.  Previously it had been made of a length of 1/4-20 threaded rod.  With a 2" movement of the nut needed for full forward to reverse, some 40 turns of the crank would be needed.  Using a 5/16-18 double lead (effectively 9 turns/inch), the time needed would be cut in more than half.

Choice of this thread form had several unanticipated benefits.  First, the drill size for the tap is F, or .257".  That means that the nut can be drilled out and retapped rather than remade.  Second, the nut will pass over the 1/4-20 at the top so that the crank wheel would not need to be remade either.

The shaft consists of a 1" section 1/4" diameter with .75" threads.  Then 2.75" of 5-16-18 and then .75" of unturned 5/16 stock, all made from drill rod.  The bottom section was then attached to the lower 1/2" diameter section with loctite.

Here's the finished result:






The reversing motion is now also smoother.


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