Author Topic: Greene Automatic Cutoff Steam Engine  (Read 56566 times)

Online Jo

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Re: Greene Automatic Cutoff Steam Engine
« Reply #375 on: July 02, 2020, 05:21:31 AM »
Great news Kirk, give it time to sort itself out  ;)

Jo
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Offline Admiral_dk

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Re: Greene Automatic Cutoff Steam Engine
« Reply #376 on: July 02, 2020, 11:26:46 AM »
Quote
Great news Kirk, give it time to sort itself out  ;)

Amen to that, and best wishes

Per

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #377 on: July 11, 2020, 08:04:40 PM »
I decided to get back in the shop for a couple of hours today working on parts that don't require too much close up vision (i.e., needed to switch to reading glasses).  My last attempt at the ball joint resulted in the pocket, drilled with a 5/16" ball mill, being too small for the 5/16 ball bearing.

Given that the ball will oscillate vertically, it seems that a cylindrical pocket would work as well and probably better.  The ball I have measure .32" on the mic, so I programmed a .32" diameter pocket .16" deep in the end of 1/2" diameter drill rod.  The square enclosure was increased to .34".  After milling the first half, I found that the ball fit quite neatly in the pocket and rotated smoothly under my finger.



The moment of truth came after milling the second and parting off both pieces.  The ends fit together well without apparently squeezing the ball.



The ends of both halves need additional operations, and the ball needs to be annealed, drilled, and tapped.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #378 on: July 12, 2020, 11:04:53 PM »
Continuing on with the ball joint, the top half of the cage is machined to length, and a .13" spigot machined on the top.  The spigot centers the cage via a hole in the swing arm.



The bottom half of the cage is machine to length and a 1/8" pocket cut in the bottom.  The pocket mates with a 5-40 screw from the bottom of the swing arm to press the two halves together.



The 5/16" balls appear to be quite hard, so I heated two of them to cherry red and allowed to cool.  One had a rough surface afterwards, or at least wouldn't rotate smoothly under my finger in the cage half.  The second was acceptable, and I drilled and tapped it 3-48 through on the lathe.  A tip for fastening a small ball in a lathe chuck:  place the chuck face down on a table a drop the ball through the back.  Tighten without moving the chuck.



With the pieces assembled, the ball and screw move up and down within the cage quite well.



I need to do some more fettling on the hole in the swing arm to allow assembly.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #379 on: July 14, 2020, 10:54:38 PM »
After some enlargement of the pocket in the swing arm, I succeeded in installing the ball joint.  It seemed to work best to insert the top to engage the alignment hole, then the ball with its shaft, and then the bottom, all with the swing arm upside down.



At this point I can mount all of the parts that go onto the flywheel shaft, so I plan to make a temporary base to mount the two bearing standards.  When finished, the flywheel mounts between the standards, but for testing I'll place the standards closer together with the flywheel on the outside.  Since it descends below the plane of the base, I'll let it hang over the edge of the bench, or else raise everything.

I milled the key slots for the crank wheel and flywheel (temporary) on the shaft today.  The shaft is currently 1/2" too long, so the 1/2" long slot on one end will be removed later when the shaft is shortened.

Not being able to see anything close up without the temporary reading glasses is annoying, as I need continually to put the glasses on and off.   :wallbang:

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #380 on: July 16, 2020, 09:38:21 PM »
With the bearing standards screwed to a temporary base, I can add the governor pulley and the eccentrics to the shaft between them and attach these to the rest of the engine.



First I wanted to test the motion of the conrod, cross head, and piston to check for binding or collision. At the moment, it looks OK.

<a href="https://www.youtube.com/watch?v=p68Q044G9qU" target="_blank">http://www.youtube.com/watch?v=p68Q044G9qU</a>

Offline crueby

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Re: Greene Automatic Cutoff Steam Engine
« Reply #381 on: July 16, 2020, 09:57:36 PM »
Excellent, watching along...   :popcorn:

Offline Art K

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Re: Greene Automatic Cutoff Steam Engine
« Reply #382 on: July 17, 2020, 02:25:20 AM »
Kirk,
Looks good, the rod clears and everything.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #383 on: July 18, 2020, 01:07:06 AM »
I assembled the two eccentrics and put grub screws in them and the pulley.  Here they are ready to go onto the flywheel shaft.  Still need to drill and tap for oilers on the tops of the eccentric frames.



After mounting them and failing to take a photo, I realized the eccentric disks are facing the wrong way versus the SW model.  However, since there's space between them it may not matter.  At some point

Next I need to mount the governor gearbox and pedestal to the frame to align all three elements.

A belt/strap for the pulleys should hopefully be found before starting any timing as a log of disassembly would be needed to add it afterwards.  Any suggestions on where to look.

According to SW, the pulleys are 1.75" and .875" in diameter and 8.9" center to center.  Theoretically belt is 21.945" long.
« Last Edit: July 18, 2020, 01:40:07 AM by kvom »

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #384 on: July 19, 2020, 02:50:11 AM »
Today I needed to do one of those "I'll do it later" jobs to finish a part.  In this case I needed to add the horizontal bosses to the pedestal in order to attach the center lever to the input eccentric rod.

When I made the pedestal I just drilled and reamed a 1/2" through hole in the pedestal (plans call for .475" boss, but I didn't think it made much difference).  The plans call for yjr the rod on which the lever swings to have separate diameter for the boss and the swing arm.  For simplicity, I used a single 7/32" diameter, which was the size I'd drilled the arm.

So take some 1/2" drill rod, part off 1.5", and drill through.  Loctite into the pedestal.

The rod is 7/32" drill rod, parted off to the combined lengths of the holes in the pedestal and arm.  Both ends drilled and tapped 5-40.  Assemble with 5-40 screws on  both ends.



The pedestal is screwed to the bottom of the governor gear case with 2 3-48 screws, and the gear case to the frame with 3-48 screws.  I need to get some 3-48 socket screws as there's no room for the nut driver head inside the case.  But it's close enough for some measurements.

The eccentric rod head is attached to the swing arm with a 1"x3-48 screw for now.



Next session I need to make two rod ends and the rod to attach the swing arm to the slide.

Offline Dennis

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Re: Greene Automatic Cutoff Steam Engine
« Reply #385 on: July 20, 2020, 03:01:33 PM »
The eccentrics are looking good Kirk,  glad to see you back in the shop.  Looking forward to seeing the exhaust eccentric motion. Going from rotary motion to movement in three dimensions is quite interesting to watch.

Dennis
PS: thanks for the notes on the two drawing sheets.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #386 on: July 23, 2020, 10:58:47 PM »
Having finished the rod ends, I mounted the rod that actuates the slide to the center lever.  With the rod end aligned to the slide's center hole, it's evident that the rod(s) are a bit too long to allow the slide an even motion centered on its shelf.  It also seems that the rod end is too far from the slide.  Since I need to tap the slide's hole for a connecting rod, I'm going to wait until I see where the governor pulley lines up.  I can move the lever inward a bit as long as it clears the bracket for the exhaust rod.



Another critical item is locating the exhaust rod bracket on the bearing standard. It needs to be aligned with the other bracket on the governor pedestal, and then eventually to the bushing for the exhaust assemblies.  I removed the pulley and input eccentric so as to have a free area to position the exhaust eccentric and swing arm.

To set the height of the bracket, I stacked 1/8" parallels under the bracket until the height of the rod connecting the two brackets read the same (within 20 thou) at both brackets.  Then after disassembling the engine to free the standard, I'll have dimensions to drill the mounting holes.


Online steam guy willy

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Re: Greene Automatic Cutoff Steam Engine
« Reply #387 on: July 24, 2020, 02:41:46 AM »
Hi Kvom when I had to make a ball joint for the Beeleigh  mill engine  to make the ball sockets I used a ball ended milling cutter  as the parts were quite small to replicate the original ..lovely work happening here ...a few pics....

willy

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #388 on: July 26, 2020, 10:20:53 PM »
Willy,  I can see how you would need to make a ball socket if the shaft needs to move in 3 dimensions, plus yours are quite visible.  For my engine the fact that there's a socket isn't obvious unless you're looking for it, and the shaft moved only up and down.  I could have used a rod instead of a ball with a cylindrical pocket for the same result.  Thanks for checking in.

Today I reassembled the flywheel shaft with both eccentrics, and neither eccentric rods look close to parallel to the cylinder block.  For the exhaust rod, I may need to shim one of the brackets to line them up in the vertical plane.

I did a test assembly of the one of the exhaust valve mechanisms.  It's not obvious as first glance.



Both the grate and the brass crosshead need to screw into the threaded rod (this is temporary).  The solution is to attach the crosshead first along with the rod-end, then push it all the way into the bracket.  That should clear the grate from the end of the bracket allowing it to screw in fully so that the ends of the grate and crosshead are 1/2" apart.  I did it the hard way (rotating the crosshead with the grate already attache).   :facepalm:

Next step is to disassemble and machine the end of the bracket for a bearing.  I messed this up on the other bracket, which I will likely need to remake.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #389 on: July 27, 2020, 10:26:26 PM »
Progress today on the first exhaust valve assembly.

First job was to bore out the end of the bracket and its cover to accept the brass bearing for the actuator rod.  This is with a 5/16 endmill.



Next I needed to make the bearing from some 3/8" brass rod using the bracket to check for fit.  The parts for the bracket are shown here.  Screws are 2-56.



After assembling the complete mechanism, I was happy to see its motion is quite smooth:

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

Inserting the assembly into the end away from the crank was a nogo, although in the other end it would go but was too tight to operate.  Since I hadn't yet drilled the other grate I did so and took 9 thou off the flat.  Now the grate would slide in easily, and turning the shaft easily moved the grate back and forth.



I was also quite pleased to see that the actuator rod aligns pretty well with the bushing.  It might still need some shims, but not a lot.

 

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