Author Topic: Greene Automatic Cutoff Steam Engine  (Read 8104 times)

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #135 on: September 02, 2019, 10:04:43 PM »
After a few days spent pondering the crankshaft machining with 4th axis, the Greene didn't make a lot of progress.

Two small jobs on the lathe were done.  The brass bearings for the inlet shafts were turned to fit the bracket, and the two small brass rounds that restrain the slide from rising off its shelf were made.


Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #136 on: September 03, 2019, 10:36:28 PM »
The next parts to be attempted are the actuator housings. The attach to the front ends of the inlet shafts and "house" the actuators that contact the trips on the slide.  Here's the SW model:



The vertical hole guides the shaft of the actuator, the horizontal hole is tje 3/16" shaft, and the two small holes are for 3-48 set screws to secure the part to the shaft.

The first op is on the CNC mill drilling the inlet shaft hole and machining the side profile in some 3/8" tool steel.  The stock is 2x1".  The cut in the bottom will be made later to mate to the actuator to prevent it from turning.



Here is the actuator and housing assembly:



The upper part of the actuator shaft is threaded, and a pair of jam nuts prevents the actuator from descending too far.
« Last Edit: September 03, 2019, 10:45:29 PM by kvom »

Offline Art K

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Re: Greene Automatic Cutoff Steam Engine
« Reply #137 on: September 04, 2019, 04:03:54 AM »
Kurt,
After watching all these parts take shape I think I will stick with a simple 4 stroke. :lolb:
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 #138 on: September 05, 2019, 12:23:58 AM »
Art, I think you'd be surprised.  Nothing from bar stock so far has been problematic. 

Anyway, continuing with the catch housings this afternoon, I freed them from the parent stock and milled to target thickness.  Then mounted each in the machinist vise for drilling and tapping.



In order to round the side, I'll have to dig up a 1/8" corner rounding bit and dial it in.  That will be the last op if I even decide to bother.  Any further ops will be done while fitting the catches.


Offline Art K

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Re: Greene Automatic Cutoff Steam Engine
« Reply #139 on: September 05, 2019, 01:53:22 AM »
Kurt,
I'm sure they wouldn't be overly difficult just some peculiar shapes.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Dave Otto

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Re: Greene Automatic Cutoff Steam Engine
« Reply #140 on: September 05, 2019, 06:57:42 PM »
You have a 1/8" corner rounder; its called a CNC Mill.  :lolb:
Just surface them with a ball end mill.

Dave

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #141 on: September 06, 2019, 03:07:34 AM »
Dave, I suppose that's possible and worth a test.

In any case, today I started on the trips with a length of 1/2" drill rod on the lathe.  Drilled and tapped 3-48 3/8" deep in the end, and then turned down to 3/8" for a length of .708, and .40" for a further length of .2".



The interior of O1 drill rod doesn't turn that well, but the turned lengths aren't visible in operation.  After parting:



On the Bridgeport, mill to a width of .25" turning the block 180 degrees for each pass to ensure the result is centered.



The profile of the end was the milled on the CNC mill using a 1/8" endmill.  I wasn't paying attention to the drawing and fubared the first housing, so I'll have to remake it.  The second one turned out better.


Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #142 on: October 05, 2019, 08:18:29 PM »
Back to the shop after 2 weeks away and a week with a cold.  I made the cutoff support bracket over the past two days.  This bracket attaches to the side of the cylinder block with 4 3-48 screws and to the cutoff shelf with 2 8-32 screws, and thus supports the shelf and slide and attached parts.

Here's the first ops performed on the CNC mill.  The truncated cone is 1.025" high with the sides at an occluded angle of just over 6 degrees.  My CAM program generated a series of circular passes with DOC of .025" and increasing diameters.  Stock is 1.5" diameter Stressproof.



Parted off and machined bottom flat.



Offline Craig DeShong

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Re: Greene Automatic Cutoff Steam Engine
« Reply #143 on: October 08, 2019, 08:20:35 PM »
Lots of diddly little parts here Kirk, will be interesting to see them all go together.  :popcorn: :popcorn: :popcorn:
Craig

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #144 on: October 09, 2019, 02:47:27 AM »
I spent the past two afternoons making 6 rod ends from 1/4" square steel bar.  4 of them I previously made from brass, but I decided that didn't look correct.  The new pair is slotted and connects the bell crank on the cutoff mechanism with the governor.  I'll mention here that the depth of the slot from the SW part (.214") is too small;  I increased it to .254", and that seems to be a good number.  Some fettling needed next session before pics provided.

Offline kvom

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Re: Greene Automatic Cutoff Steam Engine
« Reply #145 on: October 11, 2019, 12:59:00 AM »
To attach the shelf to the bracket requires two 8-32 socket screws that are set into counterbored holes so that they are flush with the shelf surface.  The part's dimensions allow a max counterbore diameter of .25", which is smaller than a standard socket screw head.  The counterbore depth of .15" is also less than the height of the standard head as well.  I machines two screw heads to size on the lathe, using a piece of 1/4" aluminum rod that I had drilled and tapped.  I turned the head diameter to .246", and turned .028" off the height;  this left enough of the socket to be useful.  Here is the shelf and bracket with the two screws in place:



Then I started a partial assembly of the cutoff mechanism.