Author Topic: Greene Automatic Cutoff Steam Engine  (Read 19053 times)

Offline Dennis

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Re: Greene Automatic Cutoff Steam Engine
« Reply #330 on: May 19, 2020, 04:38:39 PM »
Hi Kirk,
Your cylinder block assembly is looking very nice.  I like the clear covers over the valves, there are always so many carefully made details that get covered up and only people who have built the engine know they are there.  I am sure the clear valve covers will be quite popular at the model shows.

When you compare your cylinder block and all the valve mechanism to the original engine in RI, you will see that the latches and levers are a little overscale.  The original components scaled down to watchmaker size parts so I felt they needed to be a little larger. 

Dennis

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #331 on: May 19, 2020, 11:40:19 PM »
I decided to make the rear bracket 50 thou taller than the plans call for and then skim a little at a time until the cross bars are level.  I had the profile cut and was about to sever it from the stock via the bandsaw when it slipped the bandsaw vise.  Of course the blade gouged the work, so that will be redone tomorrow.   :disappointed:

I'm not sure why this was necessary, but given that the front bracket's height is based on several parts on which its mounted, having accumulated errors shouldn't be too surprising.

I'm also going to remake the valve rods.  The die causes a burr at the end of the the thread that makes it hard to pass the rod through its hole.  I'll machine a groove and the end of the threads to avoid this.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #332 on: May 20, 2020, 09:21:33 PM »
Remake of the rear bracket was a success.  Now with everything screwed down tight the cross rods turn easily between the bearing pairs.   ;D

No time today to do the valve rods.

Eye operation was pushed back a week because of anesthetist's vacation.

Online zeeprogrammer

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Re: Greene Automatic Cutoff Steam Engine
« Reply #333 on: May 20, 2020, 10:50:04 PM »
I was going to ask for a family shot but that last pic does well.

I deleted previous post after thinking session in the shower.

My eyes! My eyes!

Are you going to do the railings as well? Like the ones I saw in your 1st pic in the thread?
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #334 on: May 22, 2020, 07:41:27 PM »
Zee, railings are the last thing I'm thinking about.  No OSHA back then.

I remade the valve rods, added addition set screws to the clevises, and assembled it all for a motion check:


I could start to do the same for the exhaust, but I really need to figure out the crosshead frame and try to get all the major pieces connected.  Here's a beauty shot of the cylinder block.


Offline fumopuc

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Re: Greene Automatic Cutoff Steam Engine
« Reply #335 on: May 23, 2020, 02:16:28 PM »
Hi Kirk, it is looking really great.

Kind Regards
Achim

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #336 on: May 26, 2020, 10:37:53 PM »
Finishing up a couple of small pieces before attacking the frame casting.  This is the ball socket that will live inside the pocket on the exhaust swing eccentric.



As the eccentric oscillates up and down it mst also swing laterally as it's connected to a lever.  The socket allows the shaft that connects the lever to the ball to remain horizontal.  The ball is a 5/16" diameter ball bearing, and the two halves of the socket have a 5/16" square cross section.

To machine the halves, they are profiled in the end of  a 1" diameter Stressproof steel rod.  A 5/16" ball end mill was drilled 5/32" deep in the center of each, and a 1/8" endmill then drilled the slots 1/8" deep.



Unfortunately I didn't have any 5/16" ball bearings, so have an order that is supposed to arrive Thursday.  I am wondering how the fit in the two halves will be.  I presume the ball's diameter will be quite precise, so depending on the precision of the endmill it may or may not move smoothly.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #337 on: May 29, 2020, 01:37:19 AM »
I received some 5/16" balls today, and they do not fit nicely into the pockets created by the ball mill.



Perhaps I need to program some runout into the mill.   :noidea:

On another from, I am trying to make a form tool to cut the v-notches in the crosshead frame.  The plans call for 17.74 degrees from vertical, but 18 degrees will have to serve.  Starting with a 3" length of 1" diameter O1 drill rod, I turned both ends down to 1/2" leaving the center section for a length of .65".  Each end was center drilled.



Setting the slide to 18 degrees, I turned the taper gradually for half the center section.



Then by reversing, the other side is cut at exactly the same angle.



I milled 4 flutes, the turned off one end.  Seems I did the wrong end so this will be a LH tool.   :hammerbash:



I heated the head to a cherry red color with a Map gas torch, then quenched in motor oil.



Despite this I was still able to scratch it slightly with a file, so my heat treatment likely wasn't optimal.  In any case I then reheated to anneal it, and tomorrow we'll see if it can cut CI.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #338 on: May 30, 2020, 12:09:16 AM »
The form tool idea seems to have been the correct choice to try first.  Before attempting the frame, I took an old spare casting from the Joy engine and gave it a go.



1000 rpm, 2-3 ipm feed, .01" depth of cut.

Securing the frame casting to the Bridgeport table took more time than the machining as there are not a of of good clamp surfaces that don't get in the way.  But once locked down it didn't take long to cut the V-ways.  I just advanced the cutter in by 10 thou and made a pass until both halves of the V had a machined surface.  The bottom V is further from the centerline  by 40-50 thou, meaning the bottom slipper will need to be thicker than the top to match.



The crosshead doesn't yet fit inside the channel, so I'll need to open up the side opening a bit, and potentially deeped the inside as well.

This operation was the one that bothered me the most starting out, so I'm quite happy that the little cutter worked so well.

If anyone else attempts this engine and wants to use my cutter let me know.  I think it's a one-time use tool for me.

Online Kim

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Re: Greene Automatic Cutoff Steam Engine
« Reply #339 on: May 30, 2020, 05:27:10 AM »
Neat little tool you made, Kvom.
It seemed to work quite well!
Kim

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #340 on: June 01, 2020, 03:24:33 AM »
Yesterday I did a fair amount of milling to the opening for the crosshead cavity, and now the crosshead slides nicely between the v-notches.  Fitting the slippers will need to wait until it's connected to the piston rod.  Afterwards I stood the work on its tail as before and drilled the 6 mounting holes around the flange.

I made some decent progress with the frame today in that I was able to mill away the round boss on the cylinder end and then a  bit further until I reached the opening to the crosshead side.  Took a bit of doing with the side flutes of a half inch carbide endmill at 30 thou per pass, screaming like a banshee.   :rant:

I took some pics but my phone is misbehaving and won't connect to download the photos.  I ordered a new phone online, so it will take a while to get back in business.

The issue now is that the entry hole is too narrow in one dimension to pass the packing gland.  I need to expand it for a depth of 1/8" without a good way to do it with the mill.  I think I'll need to try a 1/8" carbide endmill in my handheld high speed spindle.  I'm not sure whether it's better to clamp the work and hold the spindle, or mount the spindle in the CNC mill's holder and hold the workpiece.  The attached pic shows the opening to be milled.
« Last Edit: June 01, 2020, 03:31:29 AM by kvom »

Offline Roger B

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Re: Greene Automatic Cutoff Steam Engine
« Reply #341 on: June 01, 2020, 08:13:12 AM »
That's a complex little mechanism  :praise2:  :praise2: The form tool worked well  :ThumbsUp:  :ThumbsUp:  :wine1:
Best regards

Roger

Offline Jasonb

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Re: Greene Automatic Cutoff Steam Engine
« Reply #342 on: June 01, 2020, 10:08:03 AM »
Is the casting too long to be mounted vertically? would have thought a good size angle plate or even a smaller one on spacers would allow you to stand it on end to mill the cylinder mounting face flat, bore the hole and drill the hole PCD.

If all else fails tilt the Bridgeport's head.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #343 on: June 01, 2020, 12:56:23 PM »
I stood it on end to drill the holes, but that required lowering the Bridgeport knee to the max, and even then I had to shorten  a drill.  The piece was held in the vise only at the far end.  It was solid enough for drilling, but milling seems risky. That said, at this point I'm only risking a small endmill giving it a go. 


Offline Jasonb

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Re: Greene Automatic Cutoff Steam Engine
« Reply #344 on: June 01, 2020, 01:36:17 PM »
Can the head be swung sideways so you can let the casting go below the back of the table and then just clamp to an angle plate which will be a lot stiffer. R8 collet will also help rather than a milling chuck.