Model Engine Maker

Engines => From Plans => Topic started by: kvom on April 16, 2019, 07:49:51 PM

Title: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 16, 2019, 07:49:51 PM
I will be picking up a set of castings at NAMES for this engine.  The origins are from Historic Models and Reproductions from whom I got the castings for the Joy engine.  The plans and castings are now owned by Downriver Tools.  From their website:

Quote
- Improved Green Automatic Cut-Off Engine

This horizontal steam engine castings and drawings kit is based on the original automatic steam cut-off engine design by Nobel Green in 1838. The model has a 1 1/2 inch bore, 3 inch stroke and the flywheel is 11 Ĺ inches diameter.

This engine, built by the Providence Steam Engine Company in Providence, Rhode Island, incorporated variable steam cut-off several years before George Corliss patented his famous variable cut-off Corliss valve gear.  Our model is based on a 150 HP, 17 inch bore and 36 inch stroke Improved Green Automatic cut-Off Engine that has been restored and preserved by the New England Wireless and Steam Museum in East Greenwhich, RI.

Greenís engine design used what has been known as a detachable valve-gear.  The detachable valve-gear varies the steam cut-off point by using the engine governor to raise or lower trip points that operate levers to open the steam inlet valves.  The higher the trip point, the longer the steam inlet valve stays open allowing more steam into the engineís cylinder.   The detachable valve gear was designed by Frederick Sickels and patented in 1841.  Sickels was only interested in the marine applications of his valve gear and sold the rights to use his patent on land based engines to the Providence Steam Engine company.  Then, when George Corliss introduced his variable cut-off valve gear in the late 1840ís, the Providence Steam Engine Company sued Corliss for patent infringement.

The court battle between George Corliss and the Providence Steam Engine Company raged on for over 10 years and became a landmark court case over what can and cannot be patented.  In the course of the court battle, Corliss won an injunction preventing the Providence Steam Engine Company from building and selling the Green designed engine.  The court case was finally settled in Corlissí favor and Corlissí original patent was extended by the US patent office on the basis that the law suits had prevented Corliss from benefiting from his patent.

In 1869, the Corliss valve gear patents finally expired and the Providence Steam Engine Company began producing the Green engine again.  The Green Engine was given some minor upgrades and changes and then introduced as the ďImprovedĒ Green Automatic Cut-Off Engine even though it was basically the same engine Noble Green designed in 1838. 

Specifications:

Scale: 1 inch = 1 foot (1:12)
Cylinder: 1-1/2 inch bore x 3 inches stroke
Flywheel: 11-1/2 inches diameter
Overall size: 22-1/2 inches x 12 inches x 12 inches high

I suspect this will prove a good challenge.  The photo below is from their website and represents the only example I've seen running (twice at NAMES).  I don't know the builder's name, but he likes to surface grind as much of the parts as possible.  Mine will look a bit different color wise, and probably not as finely built.  I purchased the plans a year ago so I've had some time to get an idea where the problems will be.
Title: Re: Green Automatic Cutoff Steam Engine
Post by: crueby on April 16, 2019, 08:03:02 PM
That should be a very interesting model.... Gotta go check the popcorn kernel supply...
Title: Re: Green Automatic Cutoff Steam Engine
Post by: fumopuc on April 28, 2019, 07:53:56 PM

[/size]
Hi Kirk, here a model build from bar stock of one of our German forum member.

http://www.dampfundmehr.de/HP/green/im_bau/green_0.htm
Title: Re: Green Automatic Cutoff Steam Engine
Post by: crueby on April 28, 2019, 09:12:33 PM


Hi Kirk, here a model build from bar stock of one of our German forum member.

http://www.dampfundmehr.de/HP/green/im_bau/green_0.htm (http://www.dampfundmehr.de/HP/green/im_bau/green_0.htm)

That is a beautiful model! One bit I have never seen before is a part on the crankshaft next to the eccentric and the governor belt takeoff - looks to be hinged over to the base casting, and wobbles back and forth - some sort of oil pump? You can see it in one of the photos, and partway through the video at timestamp 1:15. Any idea what it is?
Title: Re: Green Automatic Cutoff Steam Engine
Post by: Admiral_dk on April 28, 2019, 09:19:01 PM
I might be mistaken, but look later in the video where you see the bottom two valves controlled by an axel that only oscillates a few degrees back and forth ....  :old:
Title: Re: Green Automatic Cutoff Steam Engine
Post by: crueby on April 28, 2019, 09:24:54 PM
I might be mistaken, but look later in the video where you see the bottom two valves controlled by an axel that only oscillates a few degrees back and forth ....  :old:


Aha! Thats it, that second eccentric drives  that axle in a small back and forth rotation. Clever!


Thanks!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 02, 2019, 04:04:32 PM
I picked up the castings at NAMES.  Here they are laid out on the shop floor with a 12" rule for comparison (penny might have not been indicative):

(https://pbase.com/kvom/image/169134021/large.jpg)

A test fit shows that the flywheel can be mounted on my 10EE lathe, but it's unlikely I can use it to turn the rim, given that the crossfeed is limited.  I plan on doing it with an endmill on the CNC mill.
Title: Re: Green Automatic Cutoff Steam Engine
Post by: Jasonb on May 02, 2019, 04:18:06 PM
Look a nice set of castings.

I would have thought you only need about 3/4" cross feed movement at the most to do the rim. Upside down boring bar mounted on the side of the toolpost facing you usually reaches out far enough to do face & side, run in reverse.

bdM-g6Wsc1Y
Title: Re: Green Automatic Cutoff Steam Engine
Post by: kvom on May 02, 2019, 04:34:55 PM
With the Joy engine 10" flywheels I was at the utmost to turn, and these are 11".  I probably need to make a custom tool holder.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 10, 2019, 02:02:41 AM
I have been studying the Solidworks model I got from Dennis Howe.  These are more informative than looking at individual drawings.  I spent the day assigning contrasting colors to the parts in order to see how they fit together more easily.  A zillion parts in this one.  A majority of the nuts are 3-48.

The operation of the exhaust valve is interesting as noted in a previous post.  Driven by an eccentric, the strap is connected to a pivoting part whose motion rocks the long exhaust rod *(second pic).  At the other end an oscillating linkage drives the "grate" valve, shown in the third.  Both halves of the valve have matching through slots that when matched together open the cylinder to the exhaust,  The use of multiple slots allows evacuation of more exhaust for an engine that might run a high speed.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on May 10, 2019, 02:05:54 AM
Now that is some clever engineering in that engine! I can see why the 3D model made it much clearer, the individual parts would be meaningless. The gimbals on the eccentric follower is pretty neat!
 :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on May 10, 2019, 03:38:06 AM
Just to clarify Downriver tools does not own Historic Models and Reproductions , they merely have the engines on their website to help sales .
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 10, 2019, 01:22:11 PM
Thanks for clarifying Jeff.

I have scheduled a 2 day trip June 4-5 via Boston  to visit the NE Wire and Steam museum where an original engine has been restored.  I have an expiring SW airlines credit that will pay for most of the airfare.  I haven't been back to Boston since I spent 6 months contracting there 20+ years ago.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on May 10, 2019, 01:29:22 PM
 Kirk ,The New England Wireless and Steam museum is on my must see list i hope to make the trip soon . I see from the photo of castings that you are missing the governor stand , castings arrived yesterday so I will get this casting out to you .Jeff
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: RonGinger on May 10, 2019, 05:03:52 PM
The New England Wireless and Steam Museum is well worth the visit. They have a couple big annual events, the SteamUp  is usually the first weekend in October. That day the big vertical boiler is fired up and several of the big steam engines are run.

Be sure to check ahead to see if they will be open when you want to visit- its a rather small place and not always open. The founder, who was almost always there, died a few months ago and I am not sure what the opening schedule will be.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 10, 2019, 07:04:53 PM
I just checked the website to see that they're not open every day.  Sent a message asking to visit the day I'm in MA.  If not I'll probably just head to Newport for the afternoon.  I have an airline credit that is use it or lose it, si I'll be doing the trip regardless. 
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 15, 2019, 12:10:41 AM
June 6 is volunteer workday at the museum, so I extended my trip by one day to participate.

Yesterday I decided to start the build by attacking the flywheel casting.  It's a big bugger: almost 12" diameter and probably over 20 pounds.  There's no real way to mount it on my lathe to start, so I started by reducing the lump of iron on the wheel's axis.  (These were needed in the mold to keep the wheel portion from cooling too rapidly).  Here's the setup using 123 blocks to raise it enough to clear the other lump.  Removed enough so that the remainder is inside the rim.

(https://pbase.com/kvom/image/169197695/large.jpg)

Back at it today.

Turned it over to mill the other "lump".  Now the rim can rest on the table, and the clamping is somewhat more secure.

(https://pbase.com/kvom/image/169197696/large.jpg)

Next the inside of the rim is machined to remove the draft.  This surface will be used to secure the wheel on the lathe via the 4-jaw chuck.  I was nervous about clamping too hard on the spokes, so this operation was done with many passes of 5 thou stepover.

(https://pbase.com/kvom/image/169197697/large.jpg)

Final operation on the mill was to face the side of the rim.  This gives a straight edge needed to ensure that the wheel is straight when mounted on the lathe.

(https://pbase.com/kvom/image/169197698/large.jpg)

Now for mounting on the lathe using my large 8" 4-jaw chuck, with the jaws on the inner rim.  Turning the lathe on a low speed allow verification that the inside face of the rim is close as possible to running true.  Then I centered the wheel using the inner rim as a guide.  Note that all of the machining done on the chuck side will be modified later.  Once centered, I used my 1/2" boring bar to turn the inner rim, and then faced the side of the rim and the hub.  The length of the hub was faced to close to the final size.

(https://pbase.com/kvom/image/169197699/large.jpg)

Next I turned the hub using a cutoff tool, then drilled the center 1/2" and bored to 0.855".

(https://pbase.com/kvom/image/169197700/large.jpg)

Final op for the day was to ream the center hole with the .875" reamer, which I had as this was the size of the axles on the Kozo loco.

(https://pbase.com/kvom/image/169197701/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 15, 2019, 12:13:07 AM
The face of the rim is now the reference surface for further ops, as is the center bore.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on May 15, 2019, 12:14:50 AM
Off to a great start, thats quite a big wheel.


 :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on May 15, 2019, 03:58:28 AM
Kirk , You didn't waste any time getting this project started , good job .
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 15, 2019, 10:54:24 PM
Not as long in the shop today, but some progress.  I moved the wheel from the lathe and mounted on the CNC mill table with the reference rim face down.  Centered on the bore, and then milled half of the outer rim.  Second op was to face the side of the rim to make it parallel to the reference  face.

(https://pbase.com/kvom/image/169200890/large.jpg)

Next session I will carefully move the clamps one at a time so as not to disturb zero position, then then mill the hub.  Once that is done, flip and mill the other half of the outer rim.  Surface finish looks decent, but I'll try to polish it once back on the lathe.

Turning the rim on the lathe using an upside down boring bar would have been easier, but my lathe has always refused to run in reverse.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on May 15, 2019, 10:58:45 PM
Very nice!

One suggestion I would make is before removing a clamp, add another one out on the rim on the same side as the one you are moving - I have had things shift slightly when moving them one at a time like you mention.

 :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: b.lindsey on May 16, 2019, 06:57:30 PM
Off to a great start Kirk. It's a big un but at least the other castings should be easier to hold.  Will be following along.

Bill
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 16, 2019, 07:06:37 PM
Finished the milling.

(https://pbase.com/kvom/image/169206505/large.jpg)

Slight mismatch on the rim that should be fixable later on.  Once I can get a 7/8" axle secure in the hole I could use the mill as a lathe to true it up.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 16, 2019, 11:05:28 PM
Next up are the castings for the main journals.  As the bottom surface seems the most level, I sawed off the excess of the pour and face milled.

(https://pbase.com/kvom/image/169207050/large.jpg)

Then the top surface was milled to be parallel to the bottom.

(https://pbase.com/kvom/image/169207051/large.jpg)

Then  one face was milled to provide a flat for a parallel.

(https://pbase.com/kvom/image/169207052/large.jpg)

Then the entire side could be milled flat.

(https://pbase.com/kvom/image/169207053/large.jpg)

Then it was reversed to mill the opposite side.  Dodging hot chips is not fun.

Next time in the shop I'll do the other one the same way.  My intention is to eventually machine the holes for the bearings on both pieces together.  I'll see if that's possible in the end.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dave Otto on May 16, 2019, 11:24:18 PM
It seems that the sides of the bearing castings would look better if they had been left as cast; Is there a reason that they need to be milled flat?

Dave
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 17, 2019, 12:18:11 AM
I'm too dumb to do anything but follow the drawings and 3D model.  The other three builds of which I'm aware also made the sides flat and parallel.  There was a lot of extra metal in the casting vs. the drawings, with more to come off on all 4 machined surfaces.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dave Otto on May 17, 2019, 12:43:34 AM
Makes since, I was just wondering.

Thanks,
Dave
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 18, 2019, 03:48:20 PM
Machining the tops of the bosses for the mounting screws.  Took about .160" off using precision Mark I eyeball.

(https://pbase.com/kvom/image/169213455/large.jpg)

Piece measures 3.818" tall vs. 3.54" in model.  I will remove metal from the tops of both at the same time.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 19, 2019, 03:26:08 AM
After machining the 2nd journal to the same state as the first, I clamped them together to perform the next ops on each simultaneously.

(https://pbase.com/kvom/image/169214600/large.jpg)

These ops were as follows:

1) Machine top surface to bring part height to 3.55".

2) Machine the sides to give a strip .15" high.  This removes the case surface and provides references for determining the center line of the parts.

3) Mill the center slot .75" deep to widen it to 1.374".  The bearing cap will subsequently sit on the resulting ledges, which in turn will be on the horizontal centerline of the bearing.

For the next shop session I need to further machine the side strips so that the two top surfaces are .463" across.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: sco on May 19, 2019, 11:51:42 AM
Kirk,

The starting point with the flywheel a few posts back where you started to machine the flywheel on the mill before it went on the lathe - was that using a rotary table to turn the flywheel or CNC?

The Lane and Bodley has a very similar sized flywheel (might even be the same casting) which I have hanging over me - it's way to big to fit on my lathe so was wondering about at least rough machining the rim on the mill.

Simon.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 19, 2019, 02:34:07 PM
CNC mill initially to machine the inner rim.  This allowed mounting with the 4-jaw.  A rotary table would work as well or better as long as there is a means to clamp it centered. 

Before any of that I manually milled off most of the outside area where the iron was poured so that it would clear the ways.

I am considering a fixture to mount the wheel on the mill spindle in order to get a good finish on the outer rim.  That will need to wait until the center keyway is broached.  The fixture will start with a 1" round rod turned to 7/8" leaving a collar on one end;  diameter reduced to .75" on the other.  Keyway milled on the 7/8 diameter portion.  Then the wheel is put on with keystock and resting on the collar, while the 3/4 portion is clamped into a R8 collet on the mill spindle.  Then with a lathe tool clamped in the mill vise, very fine cuts taken until the rim is smooth.  I doubt more than 10 thou needs to be removed.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on May 19, 2019, 04:06:26 PM
Do the drawings show such a thick rim? Seems this engine along with many similar US engines tended to have a much thinner section to the rim which would be nice to reproduce, you could even add dummy bolt flanges and a joint line to get the look of a two part flywheel.

(https://newsm.org/wp-content/uploads/2016/01/greene.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 19, 2019, 10:26:56 PM
The drawing shows a very thin rim, and the 3D model shows it as .16".  However, all three model builds I've seen pics for leave the cast rim quite thick.  While accuracy is nice, I suspect that having more weight on the rim helps in allowing the model to run slowly.  I don't intend to take off more than is needed for a good finish.

I'd guess that the original builders opted for thinner rims to make casting them easier (and probably less expensive).
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on May 19, 2019, 10:32:05 PM
Kirk,
I didn't even see that you got this casting at the show. I must have been to busy or... I did finally meet Jeff & his wife while I was packing up on Sunday. He gave me a few of his business cards & I will post them at shows. You are making good progress and coming up with good workarounds for machines to small for the job.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on May 19, 2019, 10:46:58 PM
The L&B and the Green automatic share the same flywheel ,and can be machined to a thin rim but I agree with Kirk I would leave it a little thicker .
I have in the works a pattern for a two piece flywheel for both of these engines , most people who bought or inquired about the castings asked why the flywheel wasn't a two piece one , trying to make every builder happy here .
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 20, 2019, 12:53:07 AM
Milled the outside edge to bring the top surface width to spec.  Then roughed the bearing cap castings to square the sides and bottom.  Also took a slight edge off the rounded ends in order to be able to obtain a center line with an edge finder.

(https://pbase.com/kvom/image/169219153/large.jpg)

Further machining of the caps will require accuracy as they fit closely to the journals as shown here:

(https://pbase.com/kvom/image/169218949/medium.jpg)

Here the bottom of the cap is to meet the internal ledge while the slots in the cap meets the top of the journal.   
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 20, 2019, 06:43:00 PM
Worked on the first bearing cap for a couple of hours this morning to get a fit to the journal:

(https://pbase.com/kvom/image/169222643/large.jpg)

Comparison with start point:

(https://pbase.com/kvom/image/169222644/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: sco on May 20, 2019, 09:50:21 PM
The L&B and the Green automatic share the same flywheel ,and can be machined to a thin rime but I agree with Kirk I would leave it a little thicker .
I have in the works a pattern for a two piece flywheel for both of these engines , most people who bought or inquired about the castings asked why the flywheel wasn't a two piece one , trying to make every builder happy here .

Thanks for confirming that Jeff.  Personally I was going to go for a thin rim as per the engine in the museum;

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on May 20, 2019, 09:56:41 PM
That bearing cap is a great fit, watching along!
 :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 20, 2019, 11:24:06 PM
I worked on the second one this afternoon, and the fit at the end is not as good.  A bit more fettling needed. 

My MSC order came in the the bushing and broach needed for the flywheel and crank disk.  Also a bunch of drill rod for future use.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 22, 2019, 11:11:28 PM
I gave the 7/8x3/16" broach a trial run on a piece of 3/8" thick CI through which I bored a 7/8" hole.  My #3 arbor press was able to handle that, but not the 1.25" thick hub of the flywheel.  One issue is that handle hits the wheel on the down stroke, and as it doesn't ratchet, I can only apply maximum pressure on a relatively short range of motion.

So I'll have to use the hydraulic shop press, which is currently employed as a rack for round stock and is blocked with a bunch of other stuff.  That will wait for next week, as I have an out of state trip for offroading to get ready for tomorrow.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 29, 2019, 11:55:13 PM
Finally got back in the shop after the long weekend.  I needed to use a press to broach the flywheel hub for a key.  3/16" B broach.

(https://pbase.com/kvom/image/169270578/large.jpg)

(https://pbase.com/kvom/image/169270579/medium.jpg)

Then milled the semi-circle in the journals for the main bearings.

(https://pbase.com/kvom/image/169270580/large.jpg)

Afterwards, since the journal was in the vise, I decided to swap the inserts in my face mill and take .01" off the sides.  Much better finish.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 30, 2019, 11:24:39 PM
A bit more progress on the journal assembly. 

Machined the bearing space into the caps.

(https://pbase.com/kvom/image/169277912/large.jpg)

(https://pbase.com/kvom/image/169277913/large.jpg)

Next job is to drill the mounting holes for #6 screws into the journals.  Normal chucks are obstructed by the sides,  but luckily I had this tiny one.  However its maximum size is 1/8".  So I first drilled through using a drill bit of that size.  The hole locations were found using the Mark I precision eyeball to center in the boss.

(https://pbase.com/kvom/image/169277914/large.jpg)

Then I reversed the piece to enlarge the holes from the bottom.

(https://pbase.com/kvom/image/169277915/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 31, 2019, 08:32:11 PM
Continuing along, I face milled both the journals and caps to within .02" of the specified 1.3" width.  I'm not sure if I want to mill them together when attached.  At present this looks good enough as the width is not a critical dimension.   Then drilled and tapped the tops of the journals for 8-32 screws.  For the caps, I drilled from the bottom after using surface plate and 123 blocks to set the caps vertical.

(https://pbase.com/kvom/image/169285296/large.jpg)

Then reversed to spot face the holes in the tops.

(https://pbase.com/kvom/image/169285297/large.jpg)

Since a #8 washer diameter is 3/8", I used a 7/16" endmill for this operation.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Tennessee Whiskey on May 31, 2019, 09:42:07 PM
Iím silently following along  8)

Cletus
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 02, 2019, 01:29:11 AM
Thanks Eric.

Today's job was to make a start on the main bearings.  The plans call for split bearings but I can't see a need for this in a model that won't run much.  So the bearings will be one piece aside from a collar than will be added to one end of each.  I start with a 5" length of 1.875" hex brass and chuck so that 3.5" are exposed.

(https://pbase.com/kvom/image/169293081/large.jpg)

Center drill and turn down to 1.245" using the journals to test for fit.

(https://pbase.com/kvom/image/169293082/large.jpg)

Drill .5x3.5".

(https://pbase.com/kvom/image/169293083/large.jpg)

Part off two pieces 1.5" long each, then drill 3/4" and bore to .846".  Then ream .875".

(https://pbase.com/kvom/image/169293085/large.jpg)

I found that my 7/8" drill rod was a tight fit, so bored to .877".  For the second bearing I skipped reaming.

(https://pbase.com/kvom/image/169293086/large.jpg)

Then for the acid test.  Assembled journals, bearings, caps and shaft on surface place, and was very happy to find that the shaft turn smoothly and that the bearing are snug even without the caps being screwed down.

(https://pbase.com/kvom/image/169293087/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 02, 2019, 01:32:59 AM
Excellent - watching along from the peanut gallery (and popcorn gallery, ... )
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 02, 2019, 06:34:17 PM
No peanuts!  Some onlookers may be allergic.   :ShakeHead:

Next casting up is the crank disk, which attaches the conrod to the driveshaft.  There's a lot of extra iron vs. the final dimensions (e.g., diameter 5" vs. 4.5, .88" thick vs. .54.). 

(https://pbase.com/kvom/image/169295619/large.jpg)

I clamped to the BP table first to machine away the extra "tabs" on the edge, and then to make an attempt to find the center.  Then drilled and reamed 1/2" hole.

(https://pbase.com/kvom/image/169295620/large.jpg)

The final center hole will obviously be 7/8".  My goal here is to have the edge of the recessed area on the conrod side "wobble" as little as possible when running, assuming that it is left "natural".  It's pretty hard to get the center exact for this, even assuming that the edge of the area can be made round.  So my plan is to rough turn the rim using a 1/2" rod as a mandrel, then use the 4 jaw on the rim and adjust until the recess runs as true as possible.  Then I'll drill and ream the center hole while still in the chuck.  We shall see.

In any case, the 1/2" mandrel has been attached with Loctite 620 and is curing.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 02, 2019, 06:47:39 PM
 :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: bouch on June 03, 2019, 02:49:42 AM
Hi there,

I just found this topic, and I'm following along.  Looks like a great project.

You, and others, might be interested in seeing what the Greene at New England Wireless and Steam looks like while running.  Here's a video from the last time I was there, the "Yankee Steam Up" from 2017.

05T-rOdp3gst=657s

The Greene starts at about the 5:20 mark...
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 03, 2019, 03:01:39 AM
Great video! Thanks for sharing!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 03, 2019, 12:02:31 PM
I'm leaving for Boston early tomorrow and will be at the Steam museum Thursday morning.  I did a consulting gig in Boston in 1998-99 and haven't been back since.  Planning to visit MFA (Fine Arts museum) tomorrow and Isabella Gardner museum on Wednesday.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on June 03, 2019, 06:21:19 PM
Hi Kirk,
I just got around to checking on the Green Engine build thread you told me you started.  I am impressed with the work you have done so far and did not expect nearly as much progress.  It is looking great.  Thank you for posting your work it will be great to follow along.

A few notes as I read through all the postings so far:

1. The photo you first posted is an engine built by John Ugo.  John and I worked together to develop the model after visiting the NEWS museum like you are doing this week.  John's engine was the prototype for the kit.  There is a video on You-Tube of another finished model running.  This one lives in Ill.  The Green Engine kit was completed shortly before Jeff took over Historic Models so there are only a few out there. 

I chose to build the Green Engine after seeing it run at NEWS and because the engine played a significant role in the history of steam power and patent law here in the United States.  Nathan Green was the main Challenger to John Corliss' domination the stationary steam engine market.  John Corliss was an excellent engineer but some people believe Green may have been the better engineer of the two.  Green originally worked for Corliss before moving on to start his own business and the two spent many years fighting court battles over patent writes and infringement.  The court battles boiled down to a question of what can be patented and had a large impact on our patent laws of today.  A very interesting story if you are into that sort of thing.

2. Simon asked about machining the flywheel with a rotary table on his mill.  Yes, that is a good way to get around a lathe that is not big enough.  I used that approach on the large Gothic Beam engine with it's 18 inch dia. flywheel.  You have to take light cuts and your arm gets tired cranking the rotary table but it will work.  As Jeff mentioned, the flywheel on the Green Engine is the same casting as the flywheel on the L&B Corliss.
 
    The rim is quite thick with enough metal to turn the inside and outside surfaces round.  I was probably overly concerned about distortion when I made that pattern,  but that was my lack of experience showing through.  On the original engine in the Grand Rapids Museum, the flywheel is hollowed out and there is metal in the model casting to do that.  The hollowed out rims were typical on large engines with these very large flywheels. 

3.  Jeff, the two piece flywheel is great news.  It will add another level of accuracy to the model.  I will look forward to seeing it.

4. Kurt, the assemblies with contrasting colors are really nice.  An excellent idea and thank you for sharing them.  The exhaust mechanism from crankshaft to sliding exhaust valve is quite complicated and your color assemblies make the working much easier to understand. 

5. Comparing the Green Engine Kit to the L&B Corliss Kit, the machining is about the same with the Green Engine having a few more complicated sub assemblies like the exhaust valve and it's driving mechanisms.  That exhaust eccentric with its wobbling yoke tends to confuse people.  Once the Green Engine is assembled, it will run quite well however it is more challenging to get everything adjusted correctly.  The sub assemblies like the exhaust mechanism and the trip levers for the inlet valves require some careful work and a lot of patience. 

Thanks again for posting your work Kurt, now that I see how far along you are, I will try to stay more current.  Hope you have a good time in New England.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 03, 2019, 10:27:15 PM
The result of the first ops on the crank disk with a 1/2" aluminum arbor glued in.  The finish on the rim and face is not as good as I expected, but I suspect there was some flexing of the arbor under the pressure of the tool.

(https://pbase.com/kvom/image/169302942/large.jpg)

After cutting off the arbor, I mounted the crank in my 8" 4-jaw chuck and faced the conrod side.  Here the finish is very good somewhat confirming my suspicion about the arbor.  In any case, the disk is still oversize in thickness (.75 vs. .54 inches) and diameter (4.9 vs 4.5).  I adjusted the jaws until the inner rim ran as true as I could get, but there's still a minor wobble.  Since I need to remove around .21" of thickness, the pocket may disappear, in which case I can machine it on the CNC mill.

(https://pbase.com/kvom/image/169302943/large.jpg)

It's ready to drill the center hole, but I decided to leave the setup as is until I get back from the trip.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on June 04, 2019, 07:03:07 AM
What was the reason for mounting it on the aluminium arbor? with nearly 3/8" of excess thickness surely it would have been easy to hold in the 4-jaw from the start and machine enough of the outer rim, face and bore all to finished size in one setting. Then simply reverse and machine to finished thickness.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 07, 2019, 12:24:15 PM
Jason,  I wasn't confident about the 4-jaw holding it securely given the draft angle on the raw rim and a good bit of flashing on the edges.

My visit to the museum in Warwick was great.  The work team there was in the process of finishing a redo of all of the steam piping to their engines, and fired up the small boiler to check their work.  After a period of warm up, they ran 4 of them including the Fitchburg and the Corliss, as well as two smaller ones.  I was told that the Greene is more difficult to run as they suspect the timing of one of the exhaust valves is off.

I was interested in whether the Greene had been painted originally.  The current frame and flywheel are a light bluish grey, but I was show that in a spot where the paint is flaking that there appears to be a dark brown color, and scraping that reveals cast iron.

One thing that impressed me on these original engines is the large number of oil cups and lubricators, seemingly every possible moving part got oil.

The museum has its annual steam-up the first Saturday in October, and it attracts hundreds of visitors.  I was told that there are tables for running model engines on both air and steam.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on June 07, 2019, 05:46:52 PM
Kirk,
Great progress on the Green & it sounds like you had a good trip to Boston. Still following along.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 11, 2019, 03:06:01 AM
I had left the crank disk in the lathe before my trip. So I was able to face down both sides to target dimensions:  1/2" thick with a .040" boss on the non-conrod side.  This eliminated the recess on that side and close to the rest on the conrod side.

The next step was just to drill/bore/ream the center 7/8".  Then I used my arbor press to broach it for a 3/16" key.  This was at the limit of hand power for me; any thicker I'd have needed to to use the hydraulic press.  Finally, drill and tapped 3 holes for 4-40 set screws at an angle from the back.  These will lock the disk on the crankshaft;  however, I didn't have any 4-40 set screws.

(https://pbase.com/kvom/image/169338979/large.jpg)

Now I needed to turn the rim down to 4.5" diameter, so I made a mandred from a piece of 7/8 drill rod.  I machined a slot 3/16" wide and .095" deep, then glued in some 3/16" square brass as a key.  The end was drilled and tapped 1/2-13.

(https://pbase.com/kvom/image/169338978/medium.jpg)

Now I could mount the crank disk on the lath with a 5C collet and turn the rim.

(https://pbase.com/kvom/image/169338977/large.jpg)

Next I used the mandrel to mount the flywheel.  This allows facing the rim, and subsequently truing the inside rim plus removing marks made by the 4-jaw chuck.  After a good deal of adjustment on with the lathe and the tool, I found a setup that will allow turning the rim across half its width.  Hopefully when I reverse the wheel I can turn the other side at the same DRO position and not have too obvious a center line.

(https://pbase.com/kvom/image/169339001/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 11, 2019, 03:20:00 AM
 :popcorn: :popcorn: :popcorn:

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 14, 2019, 01:29:45 AM
I pulled a back muscle Tuesday and it wasn't until this afternoon that I felt like having a go at the other half of the rim.  This didn't go well as it revealed some faults in the iron, as shown in the following 3 pictures.

(https://pbase.com/kvom/image/169356604/large.jpg)

(https://pbase.com/kvom/image/169356605/large.jpg)

(https://pbase.com/kvom/image/169356606/large.jpg)

I could continue turning down the rim, as it ought to be a lot thinner, but I'm wondering what alternatives there are for patching holes like these.

So I've abandoned the flywheel again and set about finishing the crank disk.  First op was to install aluminum jaws on the CNC mill vise and cut  them to hold the disk securely.  Then I drilled the hole for the crank pin with a 15/32 bit for a 3" throw, and reamed .499 for a press fit of the crank pin.  Finally formed the central pocket with a 1/4" endmill.

(https://pbase.com/kvom/image/169356607/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jo on June 14, 2019, 07:22:18 AM
I could continue turning down the rim, as it ought to be a lot thinner, but I'm wondering what alternatives there are for patching holes like these.

I would contact the original casting supplier and tell them about the holes - they should send you a replacement flywheel casting.

If it was a legacy casting set which is no longer available the options would be to fit a new rim to the existing centre which would allow for a shiny rim (but there will be a difference in the colour of the Iron between old and new :facepalm2: )  or fill it with something and have a painted rim.

Jo
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Ye-Ole Steam Dude on June 14, 2019, 11:01:47 AM
Hello Kirk,

JB-Weld will do a good job of filling in the bad spots and will machine down OK. Like Jo stated it will be a difference in color but if you plan to paint the flywheel it will not be visible.

Have a great day,
Thomas
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on June 14, 2019, 12:27:18 PM
Kirk , Let me know how you would like to proceed with the flywheel, I can send you a replacement if you find that you want one . Sorry about the flaws that you found these things are out of my control .Jeff
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 14, 2019, 12:41:28 PM
Jeff, what's the status of the 2-piece wheel?  Since this is a very long term project I could just wait for it.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on June 14, 2019, 12:52:04 PM
Hi Kirk , The two piece flywheel project would be a 6 month wait . Jeff
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on June 14, 2019, 03:00:53 PM
Hi Kirk, 
Sorry for the porosity in the flywheel rim.  The porosity looks like inclusions, did you see any sand or slag when you hit the holes?  What ever the cause, it is something I will be glad to take care of.  If you don't want to wait for Jeff's new two piece flywheel, I can send you the flywheel from the Green engine kit I saved for myself when we sold the business to Jeff.  Save the flywheel you have and bring it back to me next NAMES show. 

I have been able to save some castings using a tig welder with flashing from other castings as filler, then heat treating at a higher temperature than you would normally use for annealing.  On ground surfaces, these patches were not visible but they probably would be on a polished surface.  There is definatly enough metal left on the rim to remachine after heat treating and the center bore should shrink enough in heat treating to let us ream it to the correct size.  We have never tried this on a flywheel so it would be an interesting experiment.

Dennis


Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 14, 2019, 07:17:37 PM
At the rate I'm going, 6 months for a new casting, be it one or two piece, is not an issue.  Since it's essentially done other than the grub screws and final sizing, the wheel as is can be used for any testing that might be needed. 

There was some porosity  on the bottom of one of the journals, but that's insignificant and invisible.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 14, 2019, 11:48:09 PM
The next castings to be started are the two feet that support the cylinder.   Here's the 3D SW rendering:

(https://pbase.com/kvom/image/169359662/medium.jpg)

There's a lot of extra iron on all sides of the raw castings, so lots of chips to me made.   The important dimensions to be observed are:

- Height, since I was precise on the journal and bearing height, I want the cylinder bore to line up with the crank centerline.

- length of the top surface so that it matches the cylinder width.

Start with this:

(https://pbase.com/kvom/image/169359687/large.jpg)

Then on the bridgeport remove the pour hole remnant.  4 flute carbide at 1800 rpm and .100" DOC worked well and quickly.

(https://pbase.com/kvom/image/169359688/large.jpg)

(https://pbase.com/kvom/image/169359689/large.jpg)

Then use face mill on CNC mill to flatten the bottom.

(https://pbase.com/kvom/image/169359690/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on June 15, 2019, 02:20:10 AM
Kirk,
To bad about the flywheel, but it sounds like you can work around that. I hope your back is feeling better. I pulled a deltoid muscle and felt it in the center of my back. It was fine during the day but when I tried to sleep the dull ache drove me to visit the doctor. He gave me some pain med's and I laid off the machines at the YMCA gym.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 17, 2019, 03:57:20 AM
Some more machining on the feet.

Second op with bottom against fixed jaw, it's a matter of lining up the part by eye  to machine the first side.

(https://pbase.com/kvom/image/169369746/large.jpg)

Now I can use parallels to position for the opposite side.

(https://pbase.com/kvom/image/169369747/large.jpg)

Next, machine the top until the length of the surface is as close to 2.3" as I can determine with a steel rule and .01 divisions.

(https://pbase.com/kvom/image/169369748/large.jpg)

Afterwards, reverse and machine the bottom in order to obtain a height of .875".

Finally, machine the sides equally to obtain a thickness of 1".  While not critical, I was happy to hit it.

(https://pbase.com/kvom/image/169369749/large.jpg)

On the second I overshot by .002", so maybe the first was just luck.

Then over to the Bridgeport to mill down the bosses for the mounting screws.

(https://pbase.com/kvom/image/169369750/large.jpg)

That was all I had time for as I intended to watch the US Open golf tourney.  Those annoying burrs probably need to be ground off with the Dremel as using a file will be awkward.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 18, 2019, 12:28:52 AM
Machining finished on the feet:

(https://pbase.com/kvom/image/169372442/large.jpg)

Can't put it off forever, so made a start on the cylinder.  The bottom surface of the casting is the flattest, so used that as reference to machine the top.

(https://pbase.com/kvom/image/169372443/large.jpg)

Then turned over to face mill the base.  Turns out I over cut by 15 thou, but hopefully that won't matter.  Next time in shop we'll try to square the other 4 faces.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 18, 2019, 12:47:09 AM
         :popcornsmall:
  :popcorn: :popcorn: :popcorn:

 
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 18, 2019, 10:03:56 PM
Today I continued on the roughing of the cylinder.  First I used a long endmill on the Bridgeport to trim as close as possible the detritus sticking out from the body of the casting. 

(https://pbase.com/kvom/image/169375286/large.jpg)

Then the rest of the available time was in face milling the ends.  Since the back edge of the top face is quite straight, I used that as a reference to mount the cylinder vertically.

(https://pbase.com/kvom/image/169375287/large.jpg)

Then machined both ends removing .01" at a time until all the cast surface was gone.  Tedious but all I had to do was click a couple of buttons for each pass.  Next time in the shop I'll do the sides.  The result of milling the ends is that the cylinder's length is 4.904 vs. the 4.875 called for, 29 thou to work with.  :whoohoo:

My main concern with the cylinder is the bore.  It's a half inch longer than the Joy engine where I had taper in the bore until I bought an adjustable chucking reamer.  Other than that, there's 5 pockets to machine to size and a ton of holes.

(https://pbase.com/kvom/image/169375349/medium.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on June 19, 2019, 02:54:11 PM
Good work Kirk, and thank you for the extra work to share your build with everyone watching along. 

The cylinder block and all the parts that bolt to it make up about 2/3 of the work in building the Green engine. 

Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 19, 2019, 10:46:14 PM
Another hiccup on the way to Greeneville.  Looks like an air bubble in the cast, revealed when squaring the back side. 

(https://pbase.com/kvom/image/169379539/large.jpg)

This  looks to be possible to work around.  The core to the admission valves looks ok.  This gap is somewhat wider than the holes on both top and back.  Since nothing is attached to the back other than the exhaust valve plate at the bottom, I could cover this with a third plate so seal it.  The hole in the top is also larger than it appears, and is partially in the area where the steam inlet pipe would be.  Once again it should be possible to seal it, probably by a bridge between the two top valve chest covers.

I'm going to suspend work on this pending advice from Dennis and Jeff.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 20, 2019, 01:18:20 AM
In the meantime I played with the SW model of the cylinder to see if I could use the honed hydraulic cylinder tube I used for the Muncaster.

It seems that if I turn down the OD to 1.625 (1/16" wall), I could use this as a cylinder liner.  Any larger I'd need to change the bolt circle for the rear cylinder cover.  If that can work, then the issue of bore taper goes away.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on June 20, 2019, 01:50:15 AM
Hi Kirk , I have no problem with replacing the cylinder casting .Jeff
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Ye-Ole Steam Dude on June 20, 2019, 02:02:52 AM
Hello Kirk,

Sure hate to see the bad luck you are having with some of the castings. I see how much work you have put into these pieces. None the less your project is coming along nicely  :ThumbsUp:

Have a great day,
Thomas
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 20, 2019, 01:11:36 PM
Thanks Jeff.  New casting seems to be the better option.  I will use this one to experiment on using the hydraulic tube as a cylinder lining.


Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 20, 2019, 11:26:13 PM
Trying to make lemonade from a lemon, I mounted the cylinder block in the 4-jaw and adjusted by eye until the center of the cast bore was as close as I could get it.  The good news is that even  with the hole a bit off-center in one direction, the lathe doesn't shake at 500 rpm.   :D  The block measures straight on both sides to .004 over 4 inches.  I don't know if there is a way to adjust that, but the deviation shouldn't be significant .

(https://pbase.com/kvom/image/169384019/large.jpg)

As cast, the bore looks to be about 1-3/16" in diameter.  My current plan is to mill it larger on the CNC mill from both directions;  this will remove the flashing from the inside and provide a round surface for precise centering when back on the lathe.  Then I'll bore to 1.5" and test for taper.  If .002" or less over the length then no need for the hydraulic tube as a liner.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on June 21, 2019, 07:15:33 AM
is there any reason you are not just boring it as you have it now? Usual practice is to bung up the hole so you have something to mark out the ctr on and then set that point to run true. A bit of hardwood driven into the hole and filed flush will do or you can just hot glue or cyno a piece of 1/8" scrap plate to the end.

I would set it up so that the base clocks true and then bore, also take a skim off the end of the cylinder at the same setting ( crank shaft end) as those are the two critical faces, any differences between those and the bore won't be in line with the cross head guide.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 21, 2019, 02:27:44 PM
The hole itself isn't very round, and there is a lot of flashing inside.  It's also not precisely centered.

A skim facing cut would be part of my plan.  I just noticed that as currently mounted the wrong end is outside of the chuck.  The block is symmetric in that the valve mechanism can be attached on either side (as was the case with the original). The crosshead guide casting works only one way however.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on June 21, 2019, 03:01:56 PM
The hole itself isn't very round, and there is a lot of flashing inside.  It's also not precisely centered.

That is why you plug or cover the cored hole so you get a decent surface that you can accurately mark ctr on, then punch and finally clock the punch mark true.

Something like this where the core was rough, I hot glued a bit a aluminium over the end and marked out on that using the height gauge. This setup with faceplate and angle plate will also set your casting bottom true to the lathe axis and therefore your bore will be parallel to that.

(https://img.photobucket.com/albums/v156/jasonballamy/Hit%20n%20Miss/Robinson%20X-Type/DSC02293_zpsqstmrb8n.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 22, 2019, 08:29:02 PM
Despite the good advice from Jason, I decided to pursue my original plan and machine the rough bore before finishing by boring on the lathe.

The block is just under 5" long, and I don't have any carbide endmills with 2.5" flute length, but I did find this HSS one lurking in a drawer (from a bulk lot I bought at a sale years ago and never used).  .75" diameter and 4" flute length.

(https://pbase.com/kvom/image/169391881/large.jpg)

Unfortunately, I found that the center of the core is in the wrong location, approximately 1/4" higher than the design location.  You can see the ledge created after the first pass at a diameter of 1.55" needed to encompass the entire core wall.

(https://pbase.com/kvom/image/169391882/large.jpg)

Then in milling the other end it was even more out, indicating that the core is at an angle to base of the casting that I used as the initial reference surface when squaring the block.  For the replacement block, perhaps a thin rod through the code could serve as a "level", or at least to check against the bottom face.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on June 24, 2019, 01:49:02 PM
Good morning Kirk,

You are finding a lot of problems with the Green engine castings.  I have been bragging for years about the quality of castings from the foundry that made these castings but I am sure embarrassed by the flywheel and cylinder block you have.  I can understand that we should see an occasional inclusion or void but I can't figure out how the core could be put in at an angle.  I have always tried to leave a lot of extra metal in cylinder bores to allow for things like this thinking a few extra passes with the boring bar are better than loosing all the work already in the part.

Whatever the cause, I will replace the cylinder casting or send one to Jeff if he has already sent a casting to you, and appologize again for the problems you are encountering on this model.

Dennis



Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 25, 2019, 01:07:07 AM
Thanks Dennis. 

The location of the bore was partially my bad as I used the dimension from the top surface rather than the bottom to locate the center.  The latter is what should be used to make the piston rod at the correct height.  That said, I think using the hydraulic tube as a liner will work out well, and boring to 1.625 will cover the core position.

Since I had the current casting to experiment with, I drilled one of the exhaust cross holes using a 5/8 endmill.  The exhaust core "appeared" as expected, so that is OK.  The edges are at a bit of an angle to the base surface, once again indicating that the core isn't perfectly parallel to the base.  That should not be an issue.

I'll wait for you and Dennis to decide on the replacement, either your original one or one of his new ones.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 25, 2019, 01:12:30 AM
For the next part to attack, I've been looking at the brackets for the exhaust valves (images attached).  There are two castings for these, and the brackets themselves are mirrors of each other.

In reality, I expect these are easier to make from bar stock than the castings, and I'm tempted to order to a piece of 1.75" round grey iron to avoid the hassles of squaring the castings.  The overall size of each is approx 1.5x1x2 inches.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 25, 2019, 10:43:43 PM
I decided to make the brackets from grey iron rod, which I ordered from MSC.  So today's project is a small part of the assembly, the crosshead for the valve bracket.  Here's a 3D view:

(https://pbase.com/kvom/image/169406248/medium.jpg)

The radius on the top and bottom is .250, so the parts are made from 1/2" diameter rod.  I chose brass as the wll ride on iron guides.  The length of the part is .65".  First step is to drill on the lathe 0.7" deep with a #47 drill for 3-48 tapping.  Both ends of the rod are used, one part on each end.  Then move to the manual mill with a collet block to drill the cross hole 0.110".

(https://pbase.com/kvom/image/169406243/large.jpg)

Next position vertically to mill a 3/16" slot and then the sides to reduce the width to 0.3".

(https://pbase.com/kvom/image/169406245/large.jpg)

Back to the lathe to part off, face, and tap.

(https://pbase.com/kvom/image/169406246/large.jpg)

Finished.

(https://pbase.com/kvom/image/169406247/large.jpg)

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 29, 2019, 03:39:37 PM
Latest attempt at parts is the sliding exhaust valve grid.  That's the green part of the exhaust valve assembly:

(https://pbase.com/kvom/image/169419683/medium.jpg)

The design of this part has some non-obvious features.  One is the two cross slots;  these are needed so that both are exposed to the cylinder's exhaust port regardless of the grid's position, as the port is only .8" wide.  The other is the width of the grid openings, which is .07".  This is constrained by the distance that the exhaust eccentric motion can move.  On the real engine there are many more thin slits.

An issue with making the part as drawn is that it requires the slits to be 1/4" deep, and in two cases be contingent with the wall of the cross slots.  All of my 3/16" end mills have a flute length of 3/16" and a 1/8" diameter shaft.  So I modified the part to have a pocket within the cross slots, moved the slits outward and within the pocket, and machine the slits from the bottom to a depth of .15" max.

I cut off a 5" piece of 5/8" drill rod and secured in the square collet block with 2.5" exposed (making two parts from one piece of stock).  The part itself is 2.05" long.  Use of the vise stop means I have to establish the part zeroes only once.

(https://pbase.com/kvom/image/169419615/large.jpg)

The cross slots and pockets are machined with the same 1/4" carbide endmill.

(https://pbase.com/kvom/image/169419616/large.jpg)

Then the collect block is turned 90 degrees and the bottom half of the stock is machined away using the side flutes of the same endmill.  Then after a further 90 degree turn the slits are machined.

(https://pbase.com/kvom/image/169419617/large.jpg)

Then the stock is reversed in the collet and the second part made the same way.  Then both are cut away on the lathe with a parting tool.

It appears there is a slight bowing in the part, and when laid on a ground surface light can be seen through the center.  Stresses relieved during the machining are a likely cause.  I will see if stoning or surface grinding can flatten the bottom, since that's crucial to a  good seal with the fixed grid.  Otherwise I might remake from some 1144 stressproof steel.

The fixed and sliding valves need to live in a 5/8" hole in the cylinder block.  I had to order a 15.5mm drill and 5/8" reamer to machine these holes.  The fixed grid is attached firmly to the bottom of the hole with screws, and the sliding grid needs to move freely, so I am hoping that the reamed hole allows this without too much trouble.  As long as the seal between the two grids is good, there is no issue with some clearance between the sliding grid and the hole.

I have the intention to make the valve brackets from bar stock rather than the castings and hence ordered some 1.75" grey iron rod from MSC.  The box arrived yesterday, but no iron inside (box looked to have been damaged in transit and resealed).  Did a chat session with MSC last night to get rod re-ordered.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on June 29, 2019, 10:44:14 PM
Kirk,
You are making good progress despite unfortunate casting setbacks. At least you had the one to practice on. At work we've had boxes come in very busted up & missing contents, which were later found and returned.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 29, 2019, 11:11:39 PM
Thats quite a complex valve setup, very interesting.  The 1144 would be a good choice, gets rid of the warping.


 :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 30, 2019, 12:16:25 AM
I was intending to start work on the lower fixed grid, which I'll make from brass.  Not having any 5/8" round, I'll start with 3/4" hex and turn down to about .65". then heat in a 500 degree oven for a hour or so before turning to .625" and machining.  We'll see if we get warpage then.

I had to help with some family house moving that took up most of the day.

Since with the valves installed one can't see them working, I have in mind a test fixture.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 30, 2019, 12:25:26 AM
Doing the stress relieving bake for brass works out quite well, sometimes there is still a very slight bend, but no where near as bad as untreated pieces. Still, it can be worth leaving the final surface several thou tall then taking it down in a final truing pass when all cuts are made. On the 1144, I have not been able to detect any movement in the pieces I have cut.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 30, 2019, 02:36:23 AM
I have plenty of brass rod to make the trial, so nothing lost in trying.   :shrug:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Captain Jerry on June 30, 2019, 07:38:14 PM
Hi Kirk,


I have been watching this closely without having anything to say since I have absolutely no experience with castings.  My main interest is the valve mechanism.  I have doped out much of the Green design for cutoff but had never given much thought to the exhaust, assuming wrongly that it was like the Corliss design. Then when I saw that it was some kind of reciprocating mechanism, I was thinking spool valve but it had not occurred to me that it could be a slide valve.


Your work on the slides is nice. The slots are perfect. What sort of spotting bit do you use to locate them.  I am guessing that the fixed part of the valve will be much like the movable part and that you will use a relieving slot to reduce the depth as you have done on the moving part. It seems like a bit of clearance for the slide would be much preferred to a tight fit and that you could lapp the two faces together to assure a good seal.


All in all, this is a very interesting project and your documentation is much appreciated.


Jerry
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 01, 2019, 01:06:59 AM
Jerry,

The entire piece is done on my CNC mill.  I discovered that when only milling the slots, the endmill only pushed up a thin layer into the pocket.  So I altered the program to use the endmill to chain drill the  slots and extra .020" deep before profiling them.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 01, 2019, 01:19:23 AM
While my brass rod for the fixed valves was in the 500 degree oven, I used this setup to attempt to flatten the sliding valves.

(https://pbase.com/kvom/image/169431276/large.jpg)

My height gauge was used to level the work on the v-block, and I took passes .002" at a time.  Seems a lot better but still can see a bit of light when laid on a ground surface.

I also made a start on the four little rod ends (tan color in the sw image) that are made from 1/4" square brass rod.  One of each pair needs to be tapped 3-48 left handed so that the connecting rod acts as a turnbuckle.  I ordered a LH tap on Amazon, and it should be here in a couple of days.

Once the brass rod had cooled, I turned it down slowly until it fit my "ring gauge" that I made from some aluminum rod using the drill and reamer I got last week.

(https://pbase.com/kvom/image/169431277/large.jpg)

I'll make the parts next time out and see if I get any warpage.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 01, 2019, 11:50:30 PM
Started on the fixed exhaust grid, which is secured to the bottom of the through hole by three 3-48 screws.  The relief slots on the bottom are oriented to the side of the cylinder block that open into the exhaust core.

(https://pbase.com/kvom/image/169434834/large.jpg)

The slits on the sliding edge:

(https://pbase.com/kvom/image/169434835/large.jpg)

I left about .02" to be removed on the flat after determining that the piece did have some bowing.  After parting off the valve, I put it back in a 550 degree oven for another hour+.  Next time out I'll shave the remaining as I did with the sliding grid and see how flat I can get it.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 02, 2019, 11:32:04 PM
The connecting rod between the exhaust crosshead and the swing arm that drives it is designed to allow fine adjustment of the sliding drid position.  As seen in the model picture, it is a length of .099 diameter rod threaded 3-48 on one end and 3-48LH on the other.  A fixed nut between the two thread allows expansion of the length of the rod when turned by a small wrench.  To make this I first had to order a LH 3-48 tap from Amazon; this arrived today.  I previously made the 4 rod ends, so first I tapped two of them RH and the other two LH.

Not having a LH die, I spent most of the afternoon generating g-code for thread milling 3-48 threads.  My CAM program generates the code easily, but I have to tweak the parameter to get the proper minor diameter, and I do this by sneaking up on it until the generated thread will screw into a tapped hole.  Nuts are looser.  Once I had the depth correct, I could easily generate code for LH threads as well.

Here is the result.

(https://pbase.com/kvom/image/169438187/large.jpg)

The plans specify soldering the nut, but I think Loctite will work just a well.  I needed to drill out the threads of the nut with a .097 drill, which produces a sliding fit.  To hold these small nuts for drilling, I laid them on a flat surface and placed a a small drill chuck over it, then tightened.  The jaws of the chuck naturally aligned the nut.  The chuck has a 1/2" straight arbor that's easily mounted on the lathe/
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 06, 2019, 12:04:13 AM
My cast iron chunk arrived yesterday, so today I had a chance to work on it a bit.  The parts involved are the rear caps for the exhaust valves, and are colored in turquoise on the SW diagram.  After cutting the 12" long piece of 1/75" round grey iron into twp 6" pieces. I mounted one piece in the Monarch.  Faced the ends, and then turned a .625" boss .25" long on each end.

(https://pbase.com/kvom/image/169454080/large.jpg)

Then back to the bandsaw to slice off each end.

(https://pbase.com/kvom/image/169454081/large.jpg)

Then using a 5C collet and square collet block, the rest of the machining was straightforward.

(https://pbase.com/kvom/image/169454082/large.jpg)

The 5" piece left from cutting I cut into two 2.5" pieces; these will be used for the exhaust brackets.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on July 06, 2019, 04:33:05 PM
Hi Kirk,

Still following along, the valves are looking very good.  I like the revisions you made on the exhaust valves.  Also good planning on the machining process.

Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 08, 2019, 12:06:18 AM
Started on the first exhaust bracket, starting with a 2.5" piece of 1.75" grey cast iron rod.  On the lathe, I turned down 2" in order to remove the mill scale, then drilled and reamed the center hole .501" diameter and 1.75" deep.  After reversing in the lathe, the remaining 1/2" was turned to 1.125" diameter.  The workpiece was then mounted in a square collet block using a 1.125" 5C collet.

On the CHC mill, work zeros for all 3 axes were set at the end of the work on the centerline.  This allowed a consistent setup with a vise stop in that I needed to mill 4 sides 2 ops each with varying depths of cut.  I just set target depth as the dimension from center needed on each op.  Each side was machined at full depth with a 3/8" 4-flute carbide endmill at .050" stepover.  After doing each of the ops, I had this result:

(https://pbase.com/kvom/image/169465658/large.jpg)

Then I used the Bridgeport to cut back the edge of the hole by 1" on each side as per the plans.

(https://pbase.com/kvom/image/169465659/large.jpg)

There are several more ops to go before the part is released from the collet to work on the other end.

The second bracket is identical except that the last two CNC ops are done on opposite sides yielding a mirror image part.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 08, 2019, 05:48:13 PM
My euphoria was short lived.  Some measurements are showing that the inner portion of the bracket is narrower than drawn by a significant amount:  .608" vs. .625".  Normally these aren't critical dimensions, but here there is a bearing at the narrow end, and the tapped holes for the bearing cap won't work as drawn.  I can make them closer together and may do so, but before starting on the second bracket I wanted to investigate where the error arose.

After turning and drilling the second blank, I made some shallow flats on opposite sides on the CNC mill, and was not able to get the proper  distance between top and bottom.  It appears that the issue arises because the work is not perfectly parallel to all 4 sides of the collet block when held on one end by the collet with 2" sticking out.  So rather than cutting with the work horizontal in the vise, I believe I'll need to do so with it vertical and not using the block. 

The Red Cross wants my blood this afternoon, so any further work will have to wait.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 11, 2019, 01:48:26 AM
Today I had only a couple of hours in the shop, so since I'd already done the CAM work for this small part it was a good time to start in it.  This swing arm fastens to the end of the rod that is oscillated by an eccentric on the crankshaft.  It also attaches to the rod end of the exhaust valve crosshead and provides the impetus to move the sliding grate back and forth.  The angle at which it is attached to the oscillating rod determines the throw of the grate, and hence is a major means of tuning the valve motion. 

(https://pbase.com/kvom/image/169480207/medium.jpg)

The part is small enough to be enclosed in a 1" circle, so I machined its profile in the end of a piece of steel that I believe is an 1144 offcut from when it was used for the Joy engine valve rods.  In any case it machines very nicely.

(https://pbase.com/kvom/image/169480203/large.jpg)

Then at the Bridgeport, cut the 3/8" slot 1/2" deep.

(https://pbase.com/kvom/image/169480204/large.jpg)

Then mount on the lathe with the 4-jaw chuck using the spot drill mark to center a wiggler held in the tailstock.  Once centered, a parting tool rounds the inner end of the slot.

(https://pbase.com/kvom/image/169480205/large.jpg)

Then reverse the work in the collet and being the other end up to the same stage.

(https://pbase.com/kvom/image/169480206/large.jpg)

Next time in the shop I'll part these off, then mill soft jaws to hold the parts for finishing the other sides.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 12, 2019, 12:00:27 AM
So I was mistaken about the name of this part.  I read it as "device" mainly because the font used in Solidworks made the cl combo read as d.  In reality it was clevice which is actually clevis misspelled.  I didn't want to call it a device so just called it a swing arm.  Now that that's out of the way, let's finish it up.

I machined a soft jaw pocket matching the outer profile .3" deep, and after parting each clevis off the parent stock I was able to machine the opposite side.

(https://pbase.com/kvom/image/169483916/large.jpg)

After drilling the hole for the control rod, we're finished for now.  These will need a set screw or two to attach to the rod.  The cad model shows a through hole implying two on opposite sides, but it seems to me that with the clevis in place on the engine the inner screw could be hard to access.  So I'm leaving these undrilled for now.

Here's the clevis shown in relation to the other completed parts.

(https://pbase.com/kvom/image/169483917/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 12, 2019, 10:48:15 PM
Now that I have an endmill with 2" flute length, it's back to try again;  this time milling the two main profiles top down.  Starting with 2.5" length of 1.75" round grey iron with reamed .501" hole 1.7" deep in the center.  I turned the bottom  down to 1.125" and milled a soft jaw pocket to match.

The first profile just defines the bottom mounting face of the bracket. Milled 1.9" deep.

(https://pbase.com/kvom/image/169486141/large.jpg)

Not the greatest surface finish, so on the second profile I did two passes with a .005" roughing clearance on the first pass.  Then the second profile, also with a roughing and finishing pass.

(https://pbase.com/kvom/image/169486142/large.jpg)

The other bracket is the same but with the second profile mirrored around the Y axis.

(https://pbase.com/kvom/image/169486143/large.jpg)

Next ops will be to finish the bottom;  hopefully I'll finish both parts entirely next time in the shop.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 13, 2019, 11:17:01 PM
More progress on the brackets.  I used the CNC mill to finish the inside (relative to the cylinder block).  The following photo shows how the bracket for the cylinder cover side would be mounted.

(https://pbase.com/kvom/image/169491612/large.jpg)

The onto the Bridgeport to drill and tap holes for the bearing cap, to be made next.

(https://pbase.com/kvom/image/169491613/large.jpg)

Then mill the edges of the hole and drill and oil hole.

(https://pbase.com/kvom/image/169491614/large.jpg)

I was very happy to get to this point without screwing up.

(https://pbase.com/kvom/image/169491615/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 19, 2019, 12:48:09 AM
Having discovered the misspelling of clevis in SW, I saw that there are 4 more needed.  The overall dimensions are identical other than the fact that they are connected to rod ends of different diameter, hence the hole on the small end is larger.

I had ordered some 1144 stressproof rods from McMaster, and the steel I made the exhaust clevises from is not that.  The finish on these is a lot better.  I cleaned up CAM for the first ops, but otherwise pretty similar to the prior parts.

(https://pbase.com/kvom/image/169518421/large.jpg)

With 4 of them to do, this time I'm letting the computer cut the slots.

(https://pbase.com/kvom/image/169518422/large.jpg)

So here they are waiting for the next ops.  I'm looking to make a fixture for turning the barrel versus messing with the 4 jaw to center it.

(https://pbase.com/kvom/image/169518423/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on July 19, 2019, 01:01:40 AM
Great work, following along...
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 20, 2019, 10:06:42 PM
Thanks for looking in Chris.

Today's goal was to finish the 4 clevises, which when we left them were still attached to the ends of the 1" rods.  The first order of business was to drill and tap for 3-48 grub screws

(https://pbase.com/kvom/image/169525462/large.jpg)

(https://pbase.com/kvom/image/169525461/large.jpg)

Since I've not machined over or removed the soft jaws on the CNC mill's vise, I can re-use the profile pocket as long as I can recover the XY zeros.  My mill doesn't have working limit switches;  if it did I could have recorded the machine coords.  In this case I had the finished exhaust clevises, so I placed one in the pocket and used this pointed wiggler.

(https://pbase.com/kvom/image/169525463/large.jpg)

By jogging until the head was smooth to the barrell all around, I can expect accuracy of better than .002 in either direction.  Then I parted off the 4 clevis ends leaving ~5/8" of extra rod.  Then placed the clevis into the soft jaws, I could mill a 1/2" boss centered on the large end of the clevis.

(https://pbase.com/kvom/image/169525464/large.jpg)

Then I could mount the part on the lathe using a 1/2" collet.  This allowed me to this form the inside diameter:

(https://pbase.com/kvom/image/169525465/large.jpg)

And then to drill and ream for a 3/16" rod.

(https://pbase.com/kvom/image/169525466/large.jpg)

Then it was back the mill to use the soft jaws and mill away the remaining material and finish the "back" of each clevis.  The four are now done other then some buffing/deburring.  Todays' sessions was nearly 5 hours, longer than my usual.  If I had to make a few hundred of these I'd need to find more efficient methods.

(https://pbase.com/kvom/image/169525467/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 29, 2019, 04:06:58 AM
After a mini-vacation in Las Vegas, I was back in the shop today to start on the bearing brackets that support the two parallel rods on which the 4 clevises made previously are attached.  One pair of clevises activates the input valves and the other two attach the dash pots.

Starting with 6" length of 1" diameter stressproof rod, I milled 4 sides of the rod to obtain a rectangular bar .75" wide and .5" thick.  The CNC mill then machined the profiles of the 4 parts .22" deep.

(https://pbase.com/kvom/image/169565092/large.jpg)

Then on the Bridgeport  I milled away the bottom stock to free the parts.

(https://pbase.com/kvom/image/169565093/large.jpg)

Still a few manual ops tomorrow to complete these.  So far about 95% of the original bar is chips.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 30, 2019, 12:18:15 AM
In order to drill the center mounting hole vertically through a bracket and its cap, the two must be aligned precisely.  Here's the method I came up with.

First, align as closely as possible by eye and clamp together in the small machinist vise.  Then face mill to ensure that the two sides of both parts are parallel.

(https://pbase.com/kvom/image/169568195/large.jpg)

Then ream the two bearing holes 5/16.

(https://pbase.com/kvom/image/169568196/large.jpg)

After this, I used my new sonic cleaner to remove any oil or dirt.  I then cut 4 pieces of 5/16" drill rod to serve as alignment fixtures while the two parts are fastened together with Gorilla Glue (cyanoacrylate).

(https://pbase.com/kvom/image/169568197/large.jpg)

Next time out I'll drill the center holes for 3-48 body screws and 1/16 oil holes for the bearings.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 30, 2019, 11:55:27 PM
These brackets are proving trickier all the time.  After the glue cured overnight, I went about drilling the holes.  The smaller bracket went OK, but here the drill wandered.   :(

(https://pbase.com/kvom/image/169572185/large.jpg)

It's possible I didn't make the spotting drill hole large enough.  The camera color came out a bit weird, but the sonic cleaner leaves the steel with a greyish patina that comes off with a light rub of 1000 paper.  The steel seems to want to rust when cleaned though.

I don't want to cut another piece of stressproof right now and will wait until I have some other parts that can use the same size.

As consolation I spent the rest of the afternoon making the rod ends for the rods that suspend the dash pots.  Each pair has one 3-48 RH and one LH, so that turning the rod can adjust the height of the pots.

(https://pbase.com/kvom/image/169572186/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on July 31, 2019, 09:47:33 PM
Hi Kirk,  just getting caught up on this build.  Was sorry to see the problems you were having with the cylinder casting, sort of reminicent of the head problems I had with the Frisco build.  Hope you get a replacement casting you can work with.  The Clevises look terrific.  Great work here.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: steam guy willy on July 31, 2019, 11:58:17 PM
Hi Craig, Following along, and that is an interesting rule you have,,divided into 50ths..! i have seen  8ths 16ths  and 10ths and 100ths but never 50ths..?? is there a special reason for this ? 

willy
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 01, 2019, 03:12:17 AM
The rule is one of many I have picked up over many shows.  I could never find a rule when I was looking, so now with 20 or so scattered over the shop I can usually lay my hands on one.  No idea why the maker of this one chose 32nds.

Today I made the dash pot connecting rods.  Cut the two rods to length on the lathe using DRO to measure and my $90 Hardinge collet to hold it while I parted them.  Then thread milled the two ends of each.  After drilling out the threads of two 3-48 nuts, I glued them onto the rods.

(https://pbase.com/kvom/image/169575860/large.jpg)

The rod ends needed to be bought to 3/16 thickness.  With a clevis one one end, here's the assemblies:

(https://pbase.com/kvom/image/169575861/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 02, 2019, 12:40:30 AM
Continuing on with the inlet, this shows the parts involved:

(https://pbase.com/kvom/image/169580931/medium.jpg)

The clevis mounts on a rod that oscillates as directed by the eccentric and cutoff mechanisms.  The small end is connected to a sort of die block that sides vertically in a slot in the blue part, which serves as a crosshead.  This in turn connects to the valve via the valve stem.  The stem is 1/8" in diameter and has .8" of 5-40 thread .  For timing, the angle of the clevis on the rod determines the total stroke of the valve.  Once set, the 3 nuts on the stem adjust the proper position the of the valve.

To keep everything aligned, the valve slides in a groove and also is constrained by the steam chest cover.

My shop job for the day was to make the simple valve stems, with .8" of thread on one end and .2" on the other.  Decided to thread mill these as my mill was already set up.  Probably silly as I spent over an hour developing the code to cut the long thread.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 02, 2019, 11:42:43 PM
For the slider block, mill the profiles in some 1144 steel.

(https://pbase.com/kvom/image/169584129/large.jpg)

To remove the bottom waste, this is one of my favorite methods.  Better finish the  from the tip of an endmill.

(https://pbase.com/kvom/image/169584130/large.jpg)

Drill and tap the hole for the valve stem.

(https://pbase.com/kvom/image/169584131/large.jpg)

With valve stem attached.

(https://pbase.com/kvom/image/169584132/large.jpg)

Machine profiles of the die block on the end of some 75" bronze rod.

(https://pbase.com/kvom/image/169584133/large.jpg)

After separating from the stock and fettling for fit, assembly of clevis, slider, and die block.

(https://pbase.com/kvom/image/169584134/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 03, 2019, 06:28:12 PM
Today's work will be to start on the dashpot canister.  Here's a transparent view.

(https://pbase.com/kvom/image/169586993/medium.jpg)

The dashpot cylinder slides within the cavity, and is attached by a rod to the inlet mechanism. At cutoff, the cylinder pulls the valve shut.  On a full size engine, there's a close fit, and when the cylinder is raised a vacuum forms in the canister.  This plus the weight of the cylinder provides the force needed to close the valve.  In this model, a spring is used, so the fit of the cylinder is not as critical.

There are two castings provided for the canisters, but for me it's much easier to make them from round 1144 rod.  The two flanges fit within a 1.5" circle, and I have some 1.5" stock.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 04, 2019, 02:31:57 AM
Start with some 1.5" rod in the lathe, face, and skim turn to get the initial diameter which is used to set the DRO.

(https://pbase.com/kvom/image/169589114/large.jpg)

Then turn down to .850" diameter for a length of .675.

(https://pbase.com/kvom/image/169589115/large.jpg)

Drill a centerline hole .144" (#27) through (1" depth) here.  Then use .5" endmill in the tailstock to rough out the cylinder bore, and finish with boring bar; final diameter .575".

(https://pbase.com/kvom/image/169589116/large.jpg)

Using a parting tool, machine inner diameter to .75".

(https://pbase.com/kvom/image/169589117/large.jpg)

Then part off.  The canister is not difficult to chuck for the remaining ops, so I turned a 5/8" aluminum bar to a close fit to the canister bore and glued it in.  Subsequent ops will use a 5/8" collet and collet block to hold the piece.  At the end a blast from a torch will free the plug.

(https://pbase.com/kvom/image/169589118/large.jpg)

Next shop session I'll finish these and start on the pots.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on August 04, 2019, 03:09:51 AM
Great work, following along.   :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 06, 2019, 10:55:56 PM
I had a couple of days of frustration trying to finish the first canister.  The aluminum plus glued into the bore didn't hold properly, and the piece rotated ruining it while machining the base.  I tried Loctite instead of glue and that also failed.  I probably would have succeeded with a miniscule DOC.  So one of them was ruined, and I tried to come up with a way to hold it securely to mill out the bottom profile.  Eventually did this:

(https://pbase.com/kvom/image/169600324/large.jpg)

Three pieces of 3/16" square brass glued to the tips of chuck jaws fit into the recessed diameter and allowed a very firm hold.

For the pistons, I turned some 3/4" brass rod down to 5/8".  Then drilled and tapped one end 5-40, and parted off a 1" length.  The opposite end was drilled for a cross pin (to attach the rod end), two 3-48 set screws, and a pocket.

(https://pbase.com/kvom/image/169600322/large.jpg)

The bottom end was then turned to fit the canister with a nice sliding fit.  The top end was similarly turned down, and a grooving tool used form the bands.

(https://pbase.com/kvom/image/169600326/large.jpg)

(https://pbase.com/kvom/image/169600327/large.jpg)

The partial assembly to the rod:

(https://pbase.com/kvom/image/169600323/large.jpg)

Now I need to make another canister.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 10, 2019, 09:42:23 PM
I came up with a better sequence of ops for the canister.  After the manual turning and boring, the flange is machined on the CNC mill.

(https://pbase.com/kvom/image/169617339/large.jpg)

Then back to the lathe to groove the cylinder relief, and finally part off.  To clean up the bottom the lathe chuck gave a good enough hold so that facing with small DOC gave no problems.

Now I could finish the piston the same way as the first, turning to get a good sliding fit.

(https://pbase.com/kvom/image/169617340/large.jpg)

With these done, my next part to attack is the slide shelf.

(https://pbase.com/kvom/image/169617342/medium.jpg)

The overall dimensions are 2.5"x1"x.8".  To make a start, I cut down a 2.5" length of stressproof into a block slightly larger in the other two dimensions.

(https://pbase.com/kvom/image/169617341/large.jpg)

Most of the ops on this part will be manual on the Bridgeport.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 12, 2019, 01:50:50 AM
Today I reduced the block to the required dimensions on all three axes, then cut the three reliefs.

(https://pbase.com/kvom/image/169620892/large.jpg)

Then on to the CNC  mill where the large front pocket was milled .6" deep.  I used a 3/8" roughing mill followed by a 1/4" finishing pass.  Then spot drilled and drilled the 5 holes needed on this face.

(https://pbase.com/kvom/image/169620893/large.jpg)

Next time I'll finish with drilling in the top and the smaller pocket from the rear.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 13, 2019, 08:45:15 PM
I finished up the shelf yesterday, mostly drilling and tapping.

(https://pbase.com/kvom/image/169626654/large.jpg)

I was intending to continue with the slide.  But rather than continue to carve flat sheet from round bar, I decided to order some 1/8 and 1/4 inch sheet A1 tool steel from MSC for these flat parts.  In the interim, I attacked the small part shown in red here:

(https://pbase.com/kvom/image/169626644/large.jpg)

The view here is the bottom of the cutoff assembly.  The shelf is a light brown and the slide is grey.  The input from the governor is a rod that activates a cammed vertical motion of the rod that is attached to our red piece.  As the rod moves vertically, so does the part that engages its slot.  This part in turn is attached to the tappets via holes in the slide.  As the slide moves back and forth the tappets remain at a constant height as long as the slot has a good sliding fit that inhibits any vertical movement.

The dimensions of this "slide bracket"  fit within a 1/2" bounding circle, so I could mill the sides on the end of a piece of 1/2" drill rod.

(https://pbase.com/kvom/image/169626641/large.jpg)

Then reorient the collet block to mill the slot.  I used a 3/32" endmill, slightly smaller than the called for .10" slot width;  but a good fit with its partner is more critical than the dimension.

(https://pbase.com/kvom/image/169626642/large.jpg)

Then part of on the lathe and bring the cut off side to dimension.

(https://pbase.com/kvom/image/169626643/large.jpg)

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 16, 2019, 02:21:47 AM
Made the simple slide today.  It took a bit of work, but finally got a good sliding fit with the previous part.

(https://pbase.com/kvom/image/169637417/large.jpg)

I found a piece of 2" diameter steel rod in the shop, and am pretty sure it is left over 1144 from when I made the Joy engine conrods.  In any case I cut off a few inches, faced both ends, and machined the profiles for the input valve bracket replacement for the one ruined by a wandering drill bit.

(https://pbase.com/kvom/image/169637418/large.jpg)

To free it from the stock, I needed to part it off.  Doing this in a single deep groove is tough, and I was getting a lot of chatter and complaining from the lathe.  Solution is to cut a groove 1.5 time the width  of the parting tool, and go alternately a short depth from each side.  Tomorrow I'll machine off the backing material and hope to have better luck finishing it.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 19, 2019, 12:38:42 AM
I got the bracket and clamp separated from the root stock and glued up, but am waiting for a new #37 drill bit before proceeding. 

(https://pbase.com/kvom/image/169649255/large.jpg)

In the meantime I attacked the "trips";  these are the two parts that stand proud of the slide and activate the valves as the slide goes from side to side.  Their height above the slide is controlled by the governor.  Above a certain height the mating catch cannot slide over its trip, and no cutoff occurs.   To begin I chucked a piece of 3/8" drill rod, faced the end, and drilled/tapped for 3-48.  Then turned down to .187" for a length of .675" according to plans.

(https://pbase.com/kvom/image/169649256/large.jpg)

Checked the fit with the reamed holes in the slide.  The left the lathe setup to cut the same diameter on the other end of the stock.

(https://pbase.com/kvom/image/169649257/large.jpg)

Next part off and over to the CNC mill to machine the ends to a 1/4" square.

(https://pbase.com/kvom/image/169649258/large.jpg)

Test to check fit with the slots on the slide.

(https://pbase.com/kvom/image/169649259/large.jpg)

After facing to final length, the 20 degree angle is machined onto the top surface.  On the prototype engine, this face is slightly concave.

(https://pbase.com/kvom/image/169649260/large.jpg)

On the drawing, a threaded boss at the end is shown.  I prefer to use a screw or some threaded rod and a nut for simplicity.

(https://pbase.com/kvom/image/169649261/large.jpg)

I also used 3/16" as the diameter of the slide holes, thus allowing the work to be held with a 3/16" collet.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 20, 2019, 01:26:05 AM
Today's project is the "gauge plate", that attached to the front of the slide shelf.  It is slightly proud of the shelf, and hence provides a limit for the slide itself.  The markings on the plate aid in centering the back and forth motion of the slide.

(https://pbase.com/kvom/image/169654782/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Captain Jerry on August 20, 2019, 01:53:09 AM
This is the part that I have been waiting for anxiously.  Not for the complexity, but for the simplicity.  Designs that have stood the test of time usually have a common flavor of simplicity and this one is a great example of that.  Your parts are nicely made and your presentation is clear.  I believe that before final assembly, you try reversing the trips in the slide.


Jerry
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 20, 2019, 04:13:36 AM
I noticed they were backwards when I took the photo.   :facepalm:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on August 20, 2019, 03:29:09 PM
Nice job on the small parts Kurt.  And a good job of explaining how the parts function in use. 
To me, Green's cut off is more rugged and positive than Corliss' cut off.  I like the simpler design of Green's cut off better than the Corliss design.

Many people are aware of the court battles between Corliss and Green's backers over the patents on cut off design.  The court decisions had a major impact on the US copywrite and patent laws and the interpretation of the laws.  I think it is also interesting to know that Green actually worked for George Corliss in the early part of his career.

Thanks again for posting your work and explaining the operation of the engine.

Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 21, 2019, 01:30:45 AM
Only an hour of shop time today, so started this simple part, the "trip slide post".  It is this rod that raises the trips when it in turn is raised by action of the governor.

Plans call for .200" diameter rod.  I might have elected to use 7/32" had I planned ahead, but since the hole in the slide shelf was already drilled I ordered some drill rod of this size.  Not having a suitable 5C collet, I dug out my rubberflex collet chuck, which hasn't seen any use for quite a few years.  In reality it's a useful tool as each of the collets covers a range of diameters.  In this case, I used the 1/8-1/4 collet.

After parting off 1/25" of rod and facing the ends, I drilled one end .099" diameter x .25" deep.  A length of .099" drill rod will be loctited into the hole such that 1/2" protrudes with 1/8" of 3-48 threads.

(https://pbase.com/kvom/image/169660304/large.jpg)

The finishing op is a 1/16" through slot 3/8" long.  My 1/16" endmills have flute lengths that might not penetrate all the way through, so I elected to use a 5/64" endmill.  Here's the workholding setup on the CNC mill:

(https://pbase.com/kvom/image/169660305/large.jpg)

4-flute endmill at .02" DOC and 4 IPM feed.

Shown in position on the slide shelf:

(https://pbase.com/kvom/image/169660306/large.jpg)

A type of bell crank fits into the slot to move the rod up and down.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 27, 2019, 03:09:59 AM
After a long weekend away, I was back in the shop to attack the bell crank.  It will be fabricated in two parts, with the rotational shaft being a 1/8" rod loctited in and with a 5-40 thread on the other end.  Starting with a piece of A2 plate 1x2.75x.25", I drilled the through holes and then isolated the rotary boss using an adaptive clearance operation.  Tool was a .375" roughing endmill.

(https://pbase.com/kvom/image/169689810/large.jpg)

Next ops were the outer profile of the crank using a 1/8" endmill; here, three tabs were used retain the part within the stock.  The boss than has a finishing pass.

(https://pbase.com/kvom/image/169689811/large.jpg)

After freeing from the stock and deburring, the bottom was skimmed until the proper thickness was obtained.

(https://pbase.com/kvom/image/169689812/large.jpg)

Now the ends of the slot will need to be squared via filing until a smooth fit by the crank is obtained.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 28, 2019, 11:55:52 AM
Good deal of filing resulted in initial fit of the crank.  I also finished drilling the oil and mounting holes for the inlet bracket, so I mounted it on the shelf to check the fits.  Everything looks OK.  So next I'll finish the shaft for the crank and see how well it moves with the post.

(https://pbase.com/kvom/image/169695398/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/169717835/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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:

(https://pbase.com/kvom/image/169721171/large.jpg)

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.

(https://pbase.com/kvom/image/169721062/large.jpg)

Here is the actuator and housing assembly:

(https://pbase.com/kvom/image/169721255/large.jpg)

The upper part of the actuator shaft is threaded, and a pair of jam nuts prevents the actuator from descending too far.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K 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
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/169724748/large.jpg)

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.

(https://pbase.com/kvom/image/169724749/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on September 05, 2019, 01:53:22 AM
Kurt,
I'm sure they wouldn't be overly difficult just some peculiar shapes.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dave Otto 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
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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".

(https://pbase.com/kvom/image/169728504/large.jpg)

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

(https://pbase.com/kvom/image/169728505/large.jpg)

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

(https://pbase.com/kvom/image/169728506/large.jpg)

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.

(https://pbase.com/kvom/image/169728507/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/169853645/large.jpg)

Parted off and machined bottom flat.

(https://pbase.com/kvom/image/169853646/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong 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:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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:

(https://pbase.com/kvom/image/169876684/large.jpg)

Then I started a partial assembly of the cutoff mechanism.

(https://pbase.com/kvom/image/169876685/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on October 16, 2019, 08:57:45 PM
Been a bit behind on posting even though I've been in the shop.

I've about decided to have at least one part (governor gearbox) 3D printed in steel by Shapeways.  To test how accurately the dimensions come out, I generated a 1" cube with a number of through holes that I ordered today.  Looks like it will take a month to get here.  This will tell me which parts of the gearbox model will need to have roughing clearance material added, and thus how much finish machining will needed.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on October 27, 2019, 08:53:05 PM
Catching up on work from the past 2 weeks.  Here are the three pair of road ends I made to replace the prior brass ones.  Of the two groups, one is threaded 3-48RH and the other 3-48LH.

(https://pbase.com/kvom/image/169956943/large.jpg)

I drilled the bad cylinder block to mount the valve assembly to see how it all looks together.  I am waiting to remake the catch holder when I have some appropriate stock.

(https://pbase.com/kvom/image/169956946/large.jpg)

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on October 27, 2019, 09:01:24 PM
Impressive mechanism, watching along.   :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Johnmcc69 on October 27, 2019, 09:04:25 PM
Wow!
 There's a lot going on there.... "Fiddly" bits...

 Nice work!  :ThumbsUp:

 John
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on October 27, 2019, 09:10:47 PM
The eccentric lever is supplied as a casting.  I was tempted to just make this on CNC, but decided to see how practical the smaller castings are to machine accurately.  The first op is to machine the longest lug round so that the rest of the ops can done by holding said lug in a collet.  One side is reasonably flat, so used that surface to clamp to a 2-4-6 block.  Centering the lug was done with the mark I eyeball tool.

(https://pbase.com/kvom/image/169956947/large.jpg)

(https://pbase.com/kvom/image/169956948/large.jpg)

The other lugs were machined thusly:

(https://pbase.com/kvom/image/169956949/large.jpg)

This lever pivots on a rod from the pedestal of the governor.  This pedestal is provided as a casting, but the matching of the two halves was such that I decided to machine it from 1144 steel.  The form was roughed on the lathe.

(https://pbase.com/kvom/image/169956951/large.jpg)

After parting, the top flange was turned to the proper thickness.

(https://pbase.com/kvom/image/169956952/large.jpg)

Then on the Bridgeport the top was machined and mounting holes for 3-48 screws.

(https://pbase.com/kvom/image/169956953/large.jpg)

A flat was machined for mounting a bracket for the exhaust actuator rod, and two mounting holes were drilled and tapped 3-48.  The location of the lug for the eccentric lever was spotted with an endmill and a spotting drill in the center.

(https://pbase.com/kvom/image/169956954/large.jpg)

The lug is a piece of 1/2" drill rod that will be loctited during initial assembly.  It will extend out the proper distance so that the eccentric  lever aligns with the eccentric on the crankshaft.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on October 27, 2019, 09:15:39 PM
The bracket that mounts to the pedestal is next.  Its basic profile was machined into the end of some 1.5" 1144 rod.

(https://pbase.com/kvom/image/169956956/large.jpg)

I didn't take many pictures of the rest of the machining, or of the similar matching bracket that mounts on the standard supporting the crankshaft.  The bearings of the two brackets will need to be aligned to support the 1/4" rod that activates the exhaust.

(https://pbase.com/kvom/image/169956958/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on October 27, 2019, 09:41:21 PM
Last week I designed a test piece to see how accurate Shapeways steel printed parts might be.  I received it yesterday:

(https://pbase.com/kvom/image/169957474/large.jpg)

A nominal 1" cube with 3/4" round and square through holes and an array of 1/8" holes at the top.  My findings:

In general smaller than designed in all dimensions.  So basically I'd consider this as a casting where any critical dimensions need to be machined.  So the STL model needs extra materials overall, but the holes can be left as dimensioned since being smaller they can be machined. 

The top and bottom surfaces were both bowed out in the center slightly, while the sides were quite flat and square to each other.  Side to side measured .960".  The 3/4" round hole measured ~ .738".  Top to bottom was .996" in the center, but .991" at the corners.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on October 27, 2019, 09:55:40 PM
Very interesting experiment. Have you machined any parts they printed in steel?
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on October 27, 2019, 10:08:26 PM
That is the only part thus far.  I'm going to see how well the cube can be machined next time in the shop.  According to Shapeways the metal is stainless steel infused with bronze, approx. 60-40.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on October 28, 2019, 06:46:25 AM
Will be interested to see how you get on, I have heard a lot of this type can be difficult to machine particularly when it comes to things like tapping where you can't resort to carbide.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on October 28, 2019, 07:36:36 PM
I don't believe this material will work for my needs.  It's quite hard.  I drilled through one of the small bottom holes to enlarge for an 8-32 tap.  While I was able to both drill and tap this through hole, I found that doing so heated up the entire piece.  So lots of heat being generated.

Taking truing cuts with the side flutes of the carbide endmill went OK, but again lots of heat generated in the part.

Final and disqualifying test was attempting to drill and tap a 3-48 hole. Spotting drill penetrated, but the small #47 drill made no headway.

I checked i.materialise, but they can't print my part in steel.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on October 28, 2019, 07:58:15 PM
Bummer that it does not machine well - maybe one of the future versions (they are changing that technology very fast) will work out for us better. Thanks for sharing the experiment!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on October 30, 2019, 11:58:30 PM
Leaving the governor for the time being, I spent some time examining the casting for the steam inlet eccentric frame.  As castings go this one looks first rate, but knowledge that I can make this part from bar stock takes some of the pressure off.  The flashing around the edges was fairly easy to remove.  Where it was wide, I could clamp it in the bench vise and snap it off by twisting the casting.  Once the majority was removed I used the band sander to bring close to the outline.  I then milled away the sprue on the rod end.

In order to get the first reference surface, I clamped the end away from the rod end in the BP vise and took 25 thou off both sides of the central boss.  Since I didn't move it in the vise these two surfaces and parallel and flat.

(https://pbase.com/kvom/image/169971287/large.jpg)

Then I clamped the vise on these surfaces and used side flutes of an endmill to remove equal material from both sides.  Again, flat and parallel.

(https://pbase.com/kvom/image/169971288/large.jpg)

The next requirement will be to establish a center line for turning the rodd end, and a horizontal cut line at right angles to it.

The finished front half is to look like this:

(https://pbase.com/kvom/image/169971311/medium.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 03, 2019, 09:53:33 PM
With lateral reference surfaces established, I used the position of the rod end to establish a centerline and reference surface on its end.  The CNC mill machined the boss to 7/16" diameter.  Plans call for a 12-28 thread, and of course I didn't have a tap.  But McMaster come through with .219" drill rod and the tap.  I think the NC 12-24 is more common, but in this case it's irrelevant.  I'm sure both 10-32 and 1/4-20 would serve as well, but perhaps this is close to the prototype.

(https://pbase.com/kvom/image/169994198/large.jpg)

Once I could mount the casting in a collet block, I could do additional machining.  I didn't take pics of all the various ops, but they were a bit tedious just trying to carve the eccentric strap out of the casting.

(https://pbase.com/kvom/image/169994200large.jpg)

I cut off the small end by milling with a 1/8" endmill.  I cut almost all the way, then sawed them apart.  The machined portion of the faces allows or cleaning up without losing flatness.

This eccentric strap using a central interior groove to retain the eccentric disk.  Plans call for a 1/16" wide groove .05" deep.  I will use a 3/32" Woodruff cutter as that's what I have on-hand. I bought the cutter at an moving sale last year and had never used it, so it was time for a trial before working on the casting.  I mounted a 2" disk of cast iron that I had previously used to test my broaches, milled out the center to 1.36" diameter, and then tested the cutter.  Luckily G-Wizard can recommend f&s for these, so I cut the groove in .01" deep passes at 2.5 ipm and 450 rpm.

(https://pbase.com/kvom/image/169994199/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 05, 2019, 09:45:19 PM
Time to suck it up and machine the center of the strap.  First I set the vise stop as shown, then lightly clamped the collet block and strap without the inner piece.  The center of the hole to be machined is the surface of the flange (and also the movable jaw of the vise) for Y and the center of the collet block for X.  Then I removed the collet block to attach the inner half, and then clamped the ensemble using the vise stop to ensure the repeatability for X0.  Then the hole was machined using an outward spiral from the center and light cuts (17 thou) to 1.35".  Then a finish pass at 1.37".

(https://pbase.com/kvom/image/170006583/large.jpg)

The inner groove was then done in the same manner as for the test piece using the 3/32" Woodruff cutter.

(https://pbase.com/kvom/image/170006584/large.jpg)

Next time in the shop I'll work on the eccentric itself.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on November 05, 2019, 10:38:10 PM
Nice work Kirk, I've never made an eccentric with the center grove.  Looks like the woodruff cutter did a fine job. 
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 07, 2019, 12:05:06 AM
The plans saw to make the eccentric itself from cast iron.  But I can also make it from brass or possibly bronze.  Any thoughts on the best material?

I put that question aside and so decided to start on the exhaust eccentric strap, and altogether easier part and casting.  The casting has a "cut line" indicating where to separate the two halves.  I used this line as a means to clamp the casting straight, them cut off the sprue with endmill side flutes.

(https://pbase.com/kvom/image/170010260/large.jpg)

Then I could reverse the casting in the vise and set it level using a square.  This allowed me to machine a surface flat and parallel on the opposite side.  Once this was done I could measure across these flats to see how much to remove to get to the design width of 1.8".

(https://pbase.com/kvom/image/170010261/large.jpg)

Then I could use equal passes on each side to bring the casting to final thickness  on the upper half.

(https://pbase.com/kvom/image/170010262/large.jpg)

Next time I'll invert in the vise and thing the other half, then drill 2 mounting holes on each end before cutting the parts in two.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on November 07, 2019, 06:59:43 AM
Steel would be ideal for the eccentric, that is what I have used in the past with CI straps. Just about all the larger scale model traction engines use that combination and they are not display models.

It will also look correct on a scale model rather than blinging it up.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 07, 2019, 11:59:24 AM
Thanks Jason.  Steel it is!   :ThumbsUp:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 08, 2019, 02:12:56 AM
A bit more on the eccentric strap.  Use a 3/16" endmill to counterbore for the 4 x 2-56 clearance holes that will hold the two halves together.  Then reverse and bring the other half to thickness,  then counterbore that side as well.

(https://pbase.com/kvom/image/170015017/large.jpg)

Now ready to separate into the two halves next time out.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: steam guy willy on November 08, 2019, 02:42:53 AM
Good work there,.. and WOW that looks just like the cast-iron clutch release bearing in my Morris Minor  :lolb: :lolb:

Willy

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Kim on November 08, 2019, 05:40:03 AM
A bit more on the eccentric strap.  Use a 3/36" endmill to counterbore for the 4 x 2-56 clearance holes that will hold the two halves together.  Then reverse and bring the other half to thickness,  then counterbore that side as well.

So, is a 3/36" end mill the same as a 1/12" end mill? :)
Would that have been a 3/16" by any chance?  Or is there really a 1/12"?  I've not heard of that, but it also seems too small to use as a counter bore for a 2-56 screw.  Just curious!  :D

Nice work on your engine here. I'm enjoying the build!
Kim
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 08, 2019, 10:35:00 AM
3/16 of course.  Plenty big enough for a socket head 2-56; didn't try a model engineer hex head yet.  I suspect the head will fit but the 1/8" driver might not.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on November 08, 2019, 03:02:18 PM
Hi Kirk, thanks for all the photos and postings.  You have done a lot of work the last few weeks while I have been on the sidelines, nice to be catching up.  I like the way you use the collet block and mill vice, a new approach for me and I am going to use it on the Dickson prototype. 

I noticed the cube you had printed is all non metallic material.  Is that to help control deflection when the metal is deposited?  Too bad it came out hard, I was hoping that process could be used on more of our complicated parts.

Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 08, 2019, 05:12:29 PM
Thanks for looking in.

It's printed as stainless steel powder between layers of glue.  Then in the furnace bronze replaces the glue layers.

For small parts I really like collet blocks and a small machinist vise for holding parts, and both can be moved from one machine to another or to/from the surface plate for alignment.

To separate the halves I cut most of the way through using a 1/8" endmill at .025" per pass.

(https://pbase.com/kvom/image/170016965/large.jpg)

Then cut fully apart with a hacksaw and machined the matching surfaces flat.  To ensure I put the two halves together properly I punched a small dimple in the same end of each.

(https://pbase.com/kvom/image/170016966/large.jpg)

To move ahead on finishing this part I need to screw them together, but discovered I was down to only 1 2-56 nut.  Ordered some from AME, but in the meantime I'll have to move to something else.

(https://pbase.com/kvom/image/170016967/large.jpg)

The 3/16 counterbore does allow allows my Wiha nut driver access.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 08, 2019, 11:58:02 PM
First eccentric disk started.  I cutoff a 1.5" piece from some 1.5" diameter 1144 round bar.  Then turned a 3/4" boss on one end so that I could then mount it on my lathe's collet chuck.  I then turned a 1" boss 1/4" long in the far end, and turned from there for .343" until that section could fit inside the strap, which is nominally 1.36" in diameter.  After that I used a parting tool to mark off the approximate width of the rib that will fit the strap's internal groove.

(https://pbase.com/kvom/image/170018305/large.jpg)

Next I reversed the piece in the chuck and turned the outside of the rib to again fit the strap's opening.

(https://pbase.com/kvom/image/170018306/large.jpg)

From there is was a matter of fettling the width and height of the rib to get a good fit to the strap.  As part of the fitting, I ran a deburring blade along the outer edges of the groove on the strap, and using a parting too to square the bottom of the rib.

(https://pbase.com/kvom/image/170018307/large.jpg)

After a good little while, success.

(https://pbase.com/kvom/image/170018308/large.jpg)

I then turned off the temporary collet bosses.  The next op will be machining the collar of the offset hole, which will in turn provide a grip for the lathe chuck to drill and then bore the offset hole to fit the crankshaft.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 11, 2019, 12:45:03 AM
Continuing on with the eccentric strap, I mounted it on the CNC mill and machined a 1/4" offset boss that will be the mounting collar on the crankshaft.

(https://pbase.com/kvom/image/170027196/large.jpg)

Then I drilled a through hole with a 1/2" drill and followed with a 3/4"  Silver-Deming bit.  Offset is .140".

(https://pbase.com/kvom/image/170027197/large.jpg)

Then bored the hole to a tight sliding fit on the .875" crankshaft.

(https://pbase.com/kvom/image/170027198/large.jpg)

Plans call for 4 set screws in the collar to retain the eccentric to the crankshaft.  Once I drill and tap those this apart will be finished, and I'll need to make an essentially identical one for the second eccentric strap.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on November 11, 2019, 12:50:41 AM
Great progress.   :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on November 11, 2019, 02:22:26 AM
Kirk,
You are making good progress, the way you made the eccentric makes it look easy. Wanted to let you know I was still following along.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 13, 2019, 12:43:33 AM
Thanks for those who look in.  Love to see comments.

My 2-56 nuts arrived in the mail today, so I could continue working on the exhaust eccentric strap.  Since this can't be held easily other than in the vise, it's important to be able to find the center even with the two halved screwed together.  To mount securely in the vise with the split line along the x-axis, I milled small flats that will contact the jaws.

(https://pbase.com/kvom/image/170041000/large.jpg)

Then for the one that will be touching the fixed jaw, I measured the distance to the split line.  Then when I use an edge finder on that jaw, I can subtract this height to get the Y0 position.  X0 will just be half the distance between the ends of the line.

(https://pbase.com/kvom/image/170041002/large.jpg)

The strap mounted on the vise before machining the center:

(https://pbase.com/kvom/image/170041005/large.jpg)

And after:

(https://pbase.com/kvom/image/170041007/large.jpg)

Since I used the same g-code to mill the center, I half-expected the eccentric disc to fit this strap as well, but the strap appears a few thousand too small to fit snugly.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on November 15, 2019, 01:25:39 PM
Steady progress Kirk, and everything looks Super!.  Following along with  :popcorn: :popcorn: of course!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 18, 2019, 11:35:58 PM
Work took a bit of a holiday as I drove to Kimball TN on Friday morning for some Jeep offroading.  I had some stomach pains that night that didn't respond to antacid, so I went to a local emergency room.  They took a CT scan and diagnosed infected gallbladder.  Rather than having it treated there, I decided I was well enough to pickup up Jeep and trailer and drive back home.  Went straight to the local hospital at 3pm, admitted at 5pm, surgery at 8pm, discharged today at 5pm.  Feeling OK as long as I don't bend at the waist or cough.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on November 18, 2019, 11:38:01 PM
Ouch! Glad it all worked out okay, take it easy till its healed up.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on November 18, 2019, 11:47:00 PM
Ouch! Glad it all worked out okay, take it easy till its healed up.

Agreed, feel better soon !
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on November 19, 2019, 03:13:24 AM
So sorry to hear Kirk wish you a speedy recovery.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Admiral_dk on November 19, 2019, 11:29:16 AM
At least you got a quick diagnose and treatment  :ThumbsUp:

Wish you a speedy recovery too ...!

Per
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 23, 2019, 10:29:56 PM
After a week of healing, I ventured into the shop for a tricky final op on the exhaust eccentric strap.   This eccentric assembly has a swinging fork part that swings on two 1/8" pins that extend outward from the centers of the split line.  We went these pins to be clamped between the two halves of the strap.  In summary it's necessary to drill a hole that splits the split line on both ends.

I started by clamping one of the halves in the machinist vise with mounting screws inserted.  Between the surface plate and square, I ensured that both mounting faces were paralllel.

(https://pbase.com/kvom/image/170098495/large.jpg)

I then mounted the small vise on the Bridgeport's larger vise with its bottom against the fixed jaw.  Then an edge finder located the Y axis zero. 

(https://pbase.com/kvom/image/170098496/large.jpg)

I could then remove the smaller vise from the larger, I could then attach the other strap securely with nuts and return the vise to the Bridgeport.  The Y0 value won't have changed.  Then with edge finder I could find the center of the split line.

(https://pbase.com/kvom/image/170098497/large.jpg)

Then it remained only to spot and drill the hole.  The drill used was 7/64 as the hole will be reamed .124".  I decided against a through drill to the bottom as the drill is larger then the inner slot width.  So I turned the machinist vise over, keeping the Y0 intact, and center found the X0 point.  I repeated the drilling and was happy to see that the drill went cleanly through the first hole.  Then  reamed the holes in a single operation.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 25, 2019, 01:46:26 AM
Spent a couple of shop hours turning the eccentric disk to fit the strap.  Same process as for the inlet eccentric.  This one took a lot of filing, sanding, shaving to get a halfway decent fit the strap that would turn.

(https://pbase.com/kvom/image/170103466/large.jpg)

After fitting the two halves of the strap together with the screws tightened, the disc became too tight to turn.  OTOH, the needed clamping of the pivot pins seems reasonable.  Whether they might turn loose once the engine is running for a long period we'll have to see.  Next time I'll need to fettle the strap a bit more to get the disk to turn smoothly.

(https://pbase.com/kvom/image/170103467/large.jpg)

It appears that the interior hole in the strap is out of round; possibly clamping in the vise when milling it caused some distortion.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 29, 2019, 03:02:50 PM
To finish the eccentrics, I needed to drill and tap 4 3-48 grub screw holes around the collars.  Rather than do so individually, I cut off a short piece of 7/8" drill rod (diameter of crankshaft) and loctited both eccentrics to it.  Then holding the free end of the rod in a 7/8" collet and square block, I could quickly spot drill and drill each at 90 degrees separation around the collar.  By drilling into the shaft I avoiding internal burrs and allowed through tapping  while on the  rod.

(https://pbase.com/kvom/image/170119001/large.jpg)

(https://pbase.com/kvom/image/170119002/large.jpg)

Continuing on, I made a start on the swing yoke casting.  The surfaces of the "outer" portion are relatively flat and parallel, so clamping there in the Bridgeport vise allowed me to mill reference surfaces where the swing joint will be.  Both sides were milled without moving the work.

(https://pbase.com/kvom/image/170118997/large.jpg)

Then clamping these surfaces I milled off the sprue.

(https://pbase.com/kvom/image/170118998/large.jpg)

And at the same time the front and back of the "arm" were milled so as to be parallel to the reference surfaces.

(https://pbase.com/kvom/image/170118999/large.jpg)

The next two ops required the use of the Mark I precision eyeball.  First, I need to position the piece in the vise so that the arm was as nearly vertical as I could make it.  I used a small drill in the spindle as an alignment aid.  Once I was satisfied there, I used the same drill to determine the center of the arm and hence the centerline of the entire piece.  Given that, I could mill equal amounts from the sides of the arm to get smooth reference surfaces.

The next op also needed the same precision eyeball.  I clamped the arm in the machinist vise using a 123 block on the surface plate to ensure the work was flat.

(https://pbase.com/kvom/image/170119000/large.jpg)

Now I needed to determine the center of the round pocket that would be milled.  Moving the assembly to the bridgeport, I located the centerline of the arm with an edge finder, and then a drill bit to visually estimate the center of the circle. The DRO told me the distance from the side of the small vise.  Now I could move the CNC mill vise and duplicate the edge finding to locate the center.

(https://pbase.com/kvom/image/170119046/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 29, 2019, 03:09:53 PM
Yesterday I loaded the program to mill the circular hole.  When running, the 1/2" 4-flute carbide endmill couldn't penetrate the thin material in the center, merely pushing the work downward in the vise.   I decided to drill the center on the Bridgeport, only to find that my cobalt drill bits wouldn't cut it.  Seems the thin area cooled too quickly and became very hard.  I put a 5/16 2-flute cabide endmill in and with a good deal of force on the spindle managed to punch through.  The material is only about 1/16" thick but quite a fighter.

Using a spare 1/4" carbide endmill with a chipped end flute, I tried using the side flutes to remove the center material not caring muchly about the endmill itself.  Before quitting for Thanksgiving dinner, I milled away about half of it at very slow speed and lots of red sparks being thrown about.  Hopefully next shop session I can get rid of the rest and that the thicker sections will mill more normally.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on November 29, 2019, 03:49:44 PM
Can castings like that be annealed by heating then cooling slowly?
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 29, 2019, 04:03:04 PM
I believe for cast iron the required temperatures/times would be a lot higher than I could safely generate without a heat treat oven.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on November 29, 2019, 04:10:17 PM
You need about 880 degrees C, if you don't have an oven then an open fire or wood burner will do the trick, just leave to cool slowly in the ashes overnight. very small parts can be given a good long blast with a propane torch.

Looking at the amount of flash around the casting I wonder if the middle was meant to have any metal in there, looks like the mould halves were not weighed down enough and some liquid metal flowed into the gap.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on November 29, 2019, 09:36:47 PM
The eccentric castings didn't have a lot of material in the centers, so I suspect Jason is correct.  But the material there was quite consistent in its thickness.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on December 01, 2019, 03:22:09 PM
My friend in Apex is just starting on the yokes to his Greene engine.  It will be interesting to compare how you attack the problem as opposed to how he does it.

Great work you're doing.  I''m following along even though I don't comment as much.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 01, 2019, 04:03:03 PM
Is he posting any of his work?
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 01, 2019, 10:41:34 PM
More ops on the yoke.  I finished cleaning out the center with the 1/4" drill on the BP;  it seemed to be less hard the closer to the edge.  Then mounted on the CNC mill to relocate the center once again.

(https://pbase.com/kvom/image/170131485/large.jpg)

Then milled the center to a diameter of 1.85" using very light DOC.

(https://pbase.com/kvom/image/170131486/large.jpg)

Now it was time to thing out the casting.  I used the point of the spotting drill to estimate the center of the casting rib...

(https://pbase.com/kvom/image/170131487/large.jpg)

...and then took equal amounts off each side.

(https://pbase.com/kvom/image/170131488/large.jpg)

Next, I used a 1/8" 4-flute carbide bit to split the yoke.  .025" DOC each pass.

(https://pbase.com/kvom/image/170131489/large.jpg)

Spot and drill the mounting hole.

(https://pbase.com/kvom/image/170131490/large.jpg)

And then mill the other side of the holes flat.

(https://pbase.com/kvom/image/170131491/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on December 02, 2019, 03:43:22 PM
Craig,
Tell you friend in APEX that Dennis said Hi and I haven't forgotten about the part I promised.  still working on problems at the foundry.

Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on December 02, 2019, 03:49:46 PM
Hello everyone,
the metal in the center of the eccentric rings is flashing from a mold that didn't close all the way.  It is unfortunately common.  Kirk is correct thinking the thin metal cools very quickly and is hard as if quenched.  The thin flashing is so brittle that I remove it with a hammer and punch, it breaks out like glass and is much softer at the edges where it contacts the thicker ring.  The thicker ring slows the cooling of the flash at the edge.

Thanks for posting all of these photos and machining details Kirk.  Hope your healing process is still going well. 

Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 03, 2019, 12:49:50 AM
The piece that was cut away from the yoke supplies the clamping pieces.  First, I located and drilled the mounting holes for 2-56 screws.

(https://pbase.com/kvom/image/170137935/large.jpg)

Then parted from the main body.

(https://pbase.com/kvom/image/170137936/large.jpg)

Repeat on the other end, and we're ready for the next stage.

(https://pbase.com/kvom/image/170137937/large.jpg)

After this I cleaned up the sides of the arc to reduce their thickness, but I didn't take any pics here.

Next op will be to mill a rectangular through pocket in the central arm where a type of ball-joint will be placed.  The eccentric strap is a bit too wide and long to fit inside the yoke, so some fettling will be needed before they can live happily together.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on December 03, 2019, 01:37:19 AM
Is he posting any of his work?

No.  Unfortunately he shys away from computers which is a shame because his work is exemplary 
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 03, 2019, 12:29:26 PM
Just as well, as I'd suffer from the comparison.   :-[
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 04, 2019, 02:50:24 AM
The inside of the yoke needs to be flat for enough depth that the inner eccentric can rotate.

(https://pbase.com/kvom/image/170143140/large.jpg)

Continuing on with fitting the smaller half of the eccentric strap to the yoke.  The width was fine, but I had to take a good bit off the outer edge with the belt sander to arrive at this.

(https://pbase.com/kvom/image/170143141/large.jpg)

Then it was time to drill the pivot holes using the same technique as for the eccentric strap.  Drilling had to be done separately from each side, but my .126" reamer was just long enough to do both holes together.

(https://pbase.com/kvom/image/170143142/large.jpg)

Moment of truth when we see how well it goes together using some 1/8" drill rod as pivots.

(https://pbase.com/kvom/image/170143144/large.jpg)

Looking at the video of another build, it down't appear the the pivot ange is very great, much less that these parts can do.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: scc on December 04, 2019, 10:33:32 PM
Excellent work and detailed posting,    I'm watching and learning.        :popcorn:     Terry
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 06, 2019, 09:23:42 PM
The next op is to mill a through rectangular hole in the arm of the yoke.  To minimize filing needed to square the corners, I was hoping a 1/8" endmill would work.  When mounted on the mill, two problems became apparent.

(https://pbase.com/kvom/image/170152472)

The first was that for the end of the hole, there was still too much of the cast arc in the way.  The second problem was that the spindle would hit the arc before the bottom of the hole was reached.  Solution to the first problem was to mill away the part that was blocking the hole.

(https://pbase.com/kvom/image/170152473/large.jpg)

Then I found a 3/16" endmill in my supply that is 3" long.  A 1.6" stickout ensured that the spindle would be above the arc when the bottom of the hole was reached.

(https://pbase.com/kvom/image/170152474/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on December 06, 2019, 09:57:38 PM
Great progress, watching along...   :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: sco on December 07, 2019, 09:51:01 AM
That strap is full of challenges isn't it - you keep overcoming them though!

Keep it up,

Simon.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 07, 2019, 11:58:12 AM
The end is in sight on this one anyway. 
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 11, 2019, 01:46:56 AM
Some more progress over the last few days.

The arm of the yoke was left long to aid in securing in the vise, and now I reduced it to the specified length.  Then drilled and tapped 8-32 for a screw to secure the ball joint that will live in the "cage".

(https://pbase.com/kvom/image/170167846/large.jpg)

Then went back to work to finish the other eccentric strap and rod.  The inlet eccentric rod is 8" long and requires 3 12-28 nuts to attach it to the eccentric and a lever.  While the Solidworks model has a model of the nut as a model-scale "heavy" nut, the plans do not show the dimensions.  From the model, I fashioned the 3 nuts from 3/8" drill rod for a 5/16" wrench.  Normal fabrication using a hex collet block.  These are the only 12-28 nuts used on the engine.  Certainly the coarse 12-24 version would have worked as well,  but I had neither tap at the beginning of the build.

(https://pbase.com/kvom/image/170167847/large.jpg)

If a builder were to use standard regular nuts that use a 7/16" wrench, he will need to take this into account when finishing the eccentric strap.

Rather than pay for a 12-28 die, I created the code to thread mill the rod.  The dimensions in the plans are all given in decimal inches.  For the rod, the drawing specified #12 drill rod, which is .220" diameter.  I ordered this from McMaster, but had I thought about it more closely I've have realized that 7/32" drill rod is .219, and the thread's major diameter is .216.  I would also not habve thought I needed to use the rubberflex collet chuck to hold the rod in the mill.

(https://pbase.com/kvom/image/170167848/large.jpg)

While this worked OK, there's something about the design of the chuck that prevents it from being opened when positioned flat.  So to do the opposite end, I had to remove it from the mill, install on the lathe, and then  I could extract the rod.  It was at this point I realized the the rod would work with a 7/32 5C collet.   :facepalm:  In any case, here's the rod with its three nuts.

(https://pbase.com/kvom/image/170167849/large.jpg)

To attach it to the eccentric strap, I needed to machine a rectangular through hole into which one of the nuts could be inserted.  Since my nuts use a 5/16" wrench, I made the height of the hole 11/32".  I were to use the standard nuts from the hardware store, the hole would need to be 15/32.

(https://pbase.com/kvom/image/170167850/large.jpg)

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 14, 2019, 03:25:23 AM
Small progress:  rod end for inlet eccentric rod.

Half inch square bar on CNC mill to profile and drill the cross hole.

(https://pbase.com/kvom/image/170175985/large.jpg)

Over to Bridgeport to reduce thickness to 3/8".

(https://pbase.com/kvom/image/170175986/large.jpg)

Then lathe for the boss, and mill to drill and tap.

(https://pbase.com/kvom/image/170175987/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on December 14, 2019, 10:13:07 PM
This is some rather tedious work, but you seem to be solidly working your way through it all.  I wish my friend who is building one of these were posting because youíve both seemed to Have settled on the same approach.  Heís working a little slower than you so your progress is out ahead now.  It all looks great !!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 14, 2019, 11:42:27 PM
Craig,

As of this moment, I'm planning to drive to Cabin Fever and then spend 2 days in Washington DC.  If your Apex friend would be interested in hosting a shop visit, it's not far out of my route home.  Probably Wednesday Jan. 22.

My part-o-the-day for Saturday is a bracket that attaches to the inner bearing standard and supports the rod that activates the exhaust.  I couldn't actually find a drawing for this part, and have emailed Dennis.  However, since I do have the Solidworks part file, I didn't need a drawing. 

The profile of the part fit neatly into the bounds of a 1.5" circle, so I cut off a 2" piece of 1144 rod, faced it and mounted in the CNC mill vise between two v-blocks.  The profile was cut with a 1/2" endmill for the roughing pass, and this removed all extra material from the stock.  Then a facing pass op was done with the same endmill to form the 1/32" deep boss.

(https://pbase.com/kvom/image/170181769/large.jpg)

The finishing pass with a 1/8" endmill followed, and then the bearing hole was drilled.  The thickness of the part is 1/2".

(https://pbase.com/kvom/image/170181770)

I drilled the mounting holes on the Bridgeport before parting off from the stock.  3-48 body drill, .104".

(https://pbase.com/kvom/image/170181771/large.jpg)

Then milled out a slot to allow a nut driver to tighten the bottom mounting screw.  Two more ops needed:  an oil hole on the top, and machining the boss on the other side.  A brass or bronze bearing will be machined to fit the hole.

(https://pbase.com/kvom/image/170181772/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 18, 2019, 02:13:41 AM
I finished the bracket by machining the boss on the opposite side, and then drilling a 1/16" oil hole.

(https://pbase.com/kvom/image/170197862/large.jpg)

The next parts targeted today are the two pulley that will connect the crankshaft to the governor.  Both are 1144 Stressproof from rod.  The smaller governor pulley is 1.125" in diameter with a 1/4" wide slot for the belt.  It's secured to a shaft by two 3-48 set screws.  Simple turning job with the shaft reamed .188".

(https://pbase.com/kvom/image/170197863/large.jpg)

The larger crankshaft pulley will be turned from 2" rod, and will the project for the next session.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 19, 2019, 11:41:59 PM
The crankshaft pulley was today's task, a relatively simple turning job.  Stock is 1" cutoff of 2" round bar 1144 Stressproof.  Op 1 is to face the stock, then drill and bore center to sliding fit on .875" crankshaft.

(https://pbase.com/kvom/image/170204214/large.jpg)

Next op to to turn OD to 1.875".

(https://pbase.com/kvom/image/170204215/large.jpg)

Turn the collar to 1.125" OD, .345" width.

(https://pbase.com/kvom/image/170204216/large.jpg)

Now the collar can be gripped with a 5C collet and collet chuck, so facing to get the correct thickness of the pulley.

(https://pbase.com/kvom/image/170204217/large.jpg)

I marked off the width of the belt slot using a very thin grooving bit.

(https://pbase.com/kvom/image/170204217/large.jpg)

Then a regular parting tool cuts the belt groove.

(https://pbase.com/kvom/image/170204219/large.jpg)

All that remained was to move the the Bridgeport and drill/tap two 3-48 holes in the collar for set screws.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 21, 2019, 01:51:31 AM
I've decided to tackle at least the bottom part of the governor housing.  It's the part that houses the gears, and in addition it attaches to the side of the crosshead guide (or frame), and it this necessary to allow attachment of the part that connects a lever needed to operate the inlet valves.  I've also looked at the rest of the housing and I think it will be most easily done broken into 4 pieces.  I'll relay my efforts on that front later.

The profile of the part just barely fits inside a 1.5" circle, so again I'm milling it from 1.5" 1144 stressproof bar.  The inside cavity is spec'ed as .8", but I enlarged it to .8125 to enable me to use a 13/16 collet in making the cover later. 

(https://pbase.com/kvom/image/170209169/large.jpg)

Holes were drilled for the cover mounting screws as well as for mounting to the frame and for the pulley shaft.  I didn't photograph those ops.  But once done I moved to the Bridgeport to drill and tap the 3-48 hole for mounting the lower pedestal.

(https://pbase.com/kvom/image/170209170/large.jpg)

Then I used the side flutes of an endmill to remove the unused stock and bring the thickness of the part to .83".

(https://pbase.com/kvom/image/170209171/large.jpg)

The holes for the cover were tapped 3-48 on the tapping stand using a small chuck that I turn by hand and is quite sensitive.  Holes smaller than 5-40 can be tapped without a handle, even in steel.

(https://pbase.com/kvom/image/170209172)

All done for now.  It will require a vertical hole to be drilled to attach the other parts as well as convey the shaft for the pinion gear.

(https://pbase.com/kvom/image/170209173/large.jpg)

Beauty shot with the pedestal:

(https://pbase.com/kvom/image/170209174/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 23, 2019, 08:06:53 PM
I divided the governor gearbox into 4 fairly simple pieces that can be fabricated separately and then assembled.  There would normally be a single casting for the gearbox, but that hasn't been delivered.  And in any case I suspect machining that casting would take as much or more time and effort as this composite approach.  Here are SW images of the 4 parts and their assembly:

(https://pbase.com/kvom/image/170219350/medium.jpg)

(https://pbase.com/kvom/image/170219351/medium.jpg)

(https://pbase.com/kvom/image/170219352/medium.jpg)

(https://pbase.com/kvom/image/170219353/medium.jpg)

(https://pbase.com/kvom/image/170219349/medium.jpg)

I reduced the diameter of the center section from .800" to .75" in order to mate with the bottom.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Johnmcc69 on December 24, 2019, 02:18:14 AM
 :ThumbsUp:
 Nice work Kvom!
 What will you use for the governor gears?

 John
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 24, 2019, 12:08:40 PM
The plans specify a pair from Boston Gear.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 26, 2019, 10:59:56 PM
I made some time for the shop today, with job 1 being the single easiest part requiring machining of the entire engine.  It's the governor pulley shaft.  A piece of 3/16" drill rod with .100" on one end turned to .125".  The reduced end rides in the 1/8" hole in back of the gear chamber, and the pulley is secured with two set screws.  The shaft is retained by the bevel gear when installed.

(https://pbase.com/kvom/image/170235508/large.jpg)

(https://pbase.com/kvom/image/170235509/large.jpg)

After that beast, I did the top part of the center section of the governor.  Its profile fits within a 1.5" circle, so again I can use a length of 1144 Stressproof bar.  There are 8 CNC ops to get this far:

(https://pbase.com/kvom/image/170235510/large.jpg)

I decided to add the top fillet as it is the most visible.  It was machined with a 1/8" ball  mill, the first time i've used such a mill in this way.  Also a test as to how will my feeds and speeds calculator handles these mills.  Worked fine as you can see.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 28, 2019, 11:19:39 PM
I finished the middle piece of the governor but I didn't take any photos.  You will be able to see it in the following pics of making the top section today.  I took a length of 1144 Stressproof round bar, 7/8" diameter and cut off a 2" piece.  On the lathe drilled a #15 an inch and a half deep, then reversed to finish the through hole.  Reamed through .1885, and then faced one end to a final length of 1/94".

(https://pbase.com/kvom/image/170244331/large.jpg)

One end was turned to .625" diameter for .5"; this will be the top section of the piece.  The other end was turned to .5" diameter for .25"; this boss will connect to the middle sections hole.

(https://pbase.com/kvom/image/170244332/large.jpg)

Now using the top piece in a collet, I turned the remaining section to .75" diameter.

(https://pbase.com/kvom/image/170244333/large.jpg)

The half-angle for this section is 6 degrees, so I set the compound to turn it.  Test fit to the bottom showed I need to square the rounded corner of the boss with a parting blade and a file.

(https://pbase.com/kvom/image/170244334/large.jpg)

A 1/8" wide slot .3" deep was milled across the center of the top.  The counterbore at the top is shows as .356" diameter on the drawing.  For the time being I used a 5/16 endmill, and we'll see what is needed later.

(https://pbase.com/kvom/image/170244335/large.jpg)

The flat for the flange was machined. 

(https://pbase.com/kvom/image/170244336/large.jpg)

Beauty shot with the middle section.

(https://pbase.com/kvom/image/170244337/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on December 28, 2019, 11:47:38 PM
Watching along quietly, great progress!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on December 30, 2019, 11:51:05 PM
Before making the flange, I thought it prudent to check for clearances with the two parts that are situated between the two arms.

(https://pbase.com/kvom/image/170253069/large.jpg)

Close, but clearance is clarence as they say.  I also thought it prudent to investigate the governor top, which presents some issues in fabrication.

(https://pbase.com/kvom/image/170253070/medium.jpg)

The top is nearly 2" long and requires a through hole .25" in diameter.  The bottom section (dark blue) is .375" in diameter meaning a wall thickness of .062" to which the two asymmetric arms must be attached.  I have considered approaches using 2 or 3 individual parts, but at this point my approach is two parts, the body and the arms.  After the body is slit to allow the arms to be inserted, they will be soldered in place.  Then the 25" hole must be extended to eliminate the part of the arms that cross it.

The shape of the top is a bit arbitrary as long as the vertical dimensions of the part are observed.  The section between the two rounded "ribs" will be encircled by a two piece bracket than can rotate freely.  It will be connected to the flyballs as they spin, and as they expand outward, the top rises.  Its connection to the link in the flange is how the motion is conveyed to the cutoff mechanism.

To form the top, I imported its outline into my cam program, and used a function to create a list of points evenly spaced along the curved portion.  The spacing chosen was .050".  I was then able to print a list of the XY values of the points, where X would be the distance along the length of the part and Y the radius of the part at that point.  With some 3/4" brass rod mounted on the lathe, I drilled the .25" hole about 1.5" deep, and using the free end as X0 cut the bar to the specified radius at each point using a 1/8" parting bit.

(https://pbase.com/kvom/image/170253065/large.jpg)

To avoid overcutting I needed to use the left edge of the tool on the right side and the right edge on the left.  Then with a file and some 80-grit sandpaper I got the main portion of the steps removed.

(https://pbase.com/kvom/image/170253067/large.jpg)

The rest was cut using the same parting tool.

(https://pbase.com/kvom/image/170253068/large.jpg)

I then parted off leaving half an inch of 3/4" bar still attached.  This allowed reversing the part in the collect and drilling the through hole the rest of the way from the bottom.  The two ribs need to be rounded off so I'll make a small form tool.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: fumopuc on December 31, 2019, 07:20:46 AM
Hi Kirk, always a pleasure to follow your set ups and machining operations.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on January 01, 2020, 02:24:35 AM
Last machining of 2019; start of the flange.  As before, 1.5' Stressproof bar.

(https://pbase.com/kvom/image/170257188/large.jpg)

After parting, the width was adjusted at the Bridgeport and then the .25" slot milled.

(https://pbase.com/kvom/image/170257189/large.jpg)

As it turns out, I need to widen the slot slightly so my smallest .25" countersink bit will fit after the mounting holes are drilled.

(https://pbase.com/kvom/image/170257190/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on January 01, 2020, 03:11:42 PM
Kirk,
That all looks good, though it is a bit  convoluted to make and assemble. You make it look simple.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on January 01, 2020, 10:30:21 PM
Short session today to finish off the flange.  I widened the slot by .01" on each side.  Since the mounting holes are not in the plans, I modified the SW model to position them so that the full width countersink would be completely inside the bottom of the slot.  The holes are .15" from the center of the slot.  I'm using the same 3/16" 3-48 undercut screws from McMaster that I did for the cover.

(https://pbase.com/kvom/image/170259306/large.jpg)

There is about 1/8" of material between the mounting face and the interior hole of the upper segment.  I set the drill bit visually so that it would just avoid penetrating.  I needed a bottoming tap to get enough threads so that the screw heads are flat with the slot bottom.

(https://pbase.com/kvom/image/170259307/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on January 02, 2020, 01:26:55 AM
Nice work!  I like your straight forward methodical approach to the problem.  Still following along  :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on January 03, 2020, 11:11:17 PM
Chris, Achim, Art, Craig:  thanks for looking in.

Continuing with governor fiddly bits, we have the cutoff lever:

(https://pbase.com/kvom/image/170269365/medium.jpg)

And its shaft.  With some 3/16" drill rod chuck, I reduced the diameter to .150" over a length of .45".  End is drilled for 3-48 tap.  I used the edge of a parting blade in order to get a flat surface at the inside edge.  Then parted, reverse in the collet, and drilled the opposite end.

(https://pbase.com/kvom/image/170269366/medium.jpg)

(https://pbase.com/kvom/image/170269367/medium.jpg)

Test assembly looks good.

(https://pbase.com/kvom/image/170269368/medium.jpg)

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on January 05, 2020, 05:47:23 PM
Good Morning Kirk,
You have made good progress over the holidays.  I like your approach to building the governor.  The results look better than the castings I have.  I have three castings that I had miss-match welded up and annealed but haven't been able to machine them to look acceptable.  I think Jeff is still having trouble getting a good looking casting from the foundry. 

As you are finding out, there are a lot of small detailed parts on this model that are challenging to make.  When the model was designed, I wanted to make this part and several others on the Green engine lost wax castings.  I think they are ideal candidates for the process.  However when I started looking for a supplier, the prices were quite high and some would not accept waxes that I made and sent to them.  They wanted to charge $3000 to make tooling for each part.

There must be low volume lost wax foundries willing to work with model engineers but I was not able to find one.  All of the models I designed have several parts that would be ideal for lost wax castings so if anyone knows a good source it would be a great thing for the model engineering hobby.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on January 06, 2020, 06:13:32 PM
Continuing on with governor parts, I machined the profile of the "short link" that connects the governor top section with the cutoff lever.  7/8" 1144 rod .26" deep.

(https://pbase.com/kvom/image/170282307/large.jpg)

Next, 7/64" slots are machined on the Bridgeport.

(https://pbase.com/kvom/image/170282308/large.jpg)

After parting for the rod and machining the freed side:

(https://pbase.com/kvom/image/170282309/large.jpg)

There an issue with retaining the link and lever as there is no space for a screw between the flanges.  Most likely just some .150" diameter rod, as the bottom of the link never escapes the flanges.

I made a form tool from some tool steel previous used for another build.  After reducing the thickness at the end and milling a 10-degree relief angle on the face, I cut a 1/8" semi-circle using a 1/8" endmill.  Since it is cutting brass, I didn't bother to harden and anneal.

(https://pbase.com/kvom/image/170282310/large.jpg)

The cross arms for the top are from some .1" thick brass.

(https://pbase.com/kvom/image/170282311/large.jpg)

I am not certain the best way to attach this once I mill a slot in the brass turning.    Since it fits across a 1/4" hole in a 3/8" diameter tube, the walls are only 1/16" thick.  (The center of the part will be drilled out after fixing).  If I solder, the solder will reach only one side.  I am considering Loctite on both sides, then the powder coat will provide some adhesion as well.  Only problem is needing to heat to 400F for powder coat, and that may weaken the loctite bond.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on January 07, 2020, 09:10:14 PM
The mounting slot was cut in the top using a long 1/8" endmill.  The resulting fit is close enough that the arms can hold position from light friction.

(https://pbase.com/kvom/image/170285286/large.jpg)

I then secured the arms with loctite and left to cure 24 hours.  Then I parted off extra material at the top, and put the piece into my sonic cleaner for 20 minutes. 

(https://pbase.com/kvom/image/170285287/large.jpg)

Then powder coated with a cast iron colored powder.  The arms seem quite firmly attached, but redrilling through the center tio open up the bore will be the proof.  I may decide to do a second coat tomorrow.  TBD.  I would want to do that before parting off the base.

(https://pbase.com/kvom/image/170285288/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on January 07, 2020, 09:37:22 PM
Since it appears that getting a new cylinder casting might take some time, I've been considering how I might reproduce it from bar stock.  Since I have the Solidworks model of the part, I've come up with the following idea.  The block would be made from three separate pieces of grey cast iron.  The specifications of these parts was obtained by defining two planes through the part that represent the boundaries.  The three parts themselves were then generated from separate copies where one or two "extrude cut" features removed everything but the desired material.  Here are the top, middle, and bottom:

(https://pbase.com/kvom/image/170285291/large.jpg)

(https://pbase.com/kvom/image/170285290/large.jpg)

(https://pbase.com/kvom/image/170285289/large.jpg)

The top and bottom could be machined using a single piece of iron 1x2.5x12", $56.74 from McMaster.

The center would use a piece 2.625x2.5x12", $74.81 from McMaster (enough for 2 pieces as 1' is the shortest length).

So $150 with shipping. 

The casting took a good deal of work to square, and there's always the issue of ensuring that the cores are correct relative to the final dimensions.  Using bars, the pieces would be aligned with dowel pins, and as long as the mating surfaces are very flat there should be no issue with air leakage from one end to the other.  There's also a few places where the machining would be simplified.  For example,  the bottom exhaust ports through the cylinder bore would require a very long endmill, while with the bars they would be machined from the bottom.

Another advantage is that a booboo isn't as bad.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on January 10, 2020, 11:30:17 PM
The next governor part is called the "rotating clamp".  Rotating because it attaches to the fly balls and rotates with them, and clamp because it goes loosely around the governor top and raises/lowers it according to the fly ball positions.  Like many other small parts, I first cut the top and bottom profile in the end of some 1.5" 1144 steel rod, to a depth of .25".

(https://pbase.com/kvom/image/170294552/large.jpg)

After parting them off at the lathe and cleaning up, they were clamped in the small vise using some 1/8" brass rod for alignment.

(https://pbase.com/kvom/image/170294553/large.jpg)

A hole was then machined in the center. I settled on .382" diameter after measuring the governor top.

It was then necessary to remove the powder coat where the clamp would mount, and make small adjustments until a good fit was attained.

(https://pbase.com/kvom/image/170294554/large.jpg)

The plans call for special pins to join the two halves, but I see no reason not to use 5-40 screws.  These long screws have non threaded sections that fill the slots, so only some shortening is needed.

(https://pbase.com/kvom/image/170294555/large.jpg)

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 03, 2020, 09:31:00 PM
After drilling out the center of the top and turning off the remaining brass from the bottom, I mounted the upper section of the governor in the lathe and bored the top to give a good sliding fit to the top.  Unfortunately my fears came true in the that 620 loctite didn't survive the power coat oven with sufficient strength, and both arms came loose.  I ordered some Loctite 633, which is supposed to fill in a loose slip fit better, but has even less heat tolerance (180C).  I'll recoat the top and then re-glue the arms when cool.

In the meantime came Cabin Fever and a pretty bad cold, so nothing done for a couple of weeks.  The next part is the governor cutoff lever, which transfers the vertical motion of the top to the rod that raises and lowers the cutoff catches.  For this part I used some 1/8" thick stainless 303 bar that Chris sent me.  I drilled and machined the profile while overhanging the vise.  The part is .1" thick so some material left for support at the end.

(https://pbase.com/kvom/image/170378982/large.jpg)

Then over to the Bridgeport to mill away the bottom that remained.

(https://pbase.com/kvom/image/170378983/large.jpg)

The next part is the damper pot.  The damper system smooths any rapid motion of the governor.  As the fly balls moves it, the top moves with it a disk that is a type of piston within this pot, which is filled with oil.  The oil's viscosity acts to resist the motion until enough oil has flowed through a hole in the damper disc.

I made this from some 5/8" brass rod, mainly to reuse the form tool on the rim.  I doubt that the form tool would be effective against steel.  Since I expect the pot to be powder coated, using brass wasn't an issue.  It's all lathe work.  The post is attached to the governor middle section with a flat head 3-48 screw.  The hole is countersunk to provide a flat bottom.

(https://pbase.com/kvom/image/170378984/large.jpg)

(https://pbase.com/kvom/image/170378985/large.jpg)

The damper disc is made from 3/8" drill rod.  The smaller damper hold is 1/16", while the larger hole is tapped 3-48 for its connecting rod.

(https://pbase.com/kvom/image/170378987/large.jpg)

The connecting rod is 1.5" of .099 drill rod threaded at both ends.  The rod end connects to the longer of the two arms of the governor top.

(https://pbase.com/kvom/image/170378988/large.jpg)

(https://pbase.com/kvom/image/170378989/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 03, 2020, 09:34:32 PM
The engine requires a number of different size steel balls, including the fly balls and the ball joint for the exhaust eccentric.  Rather than buy large bags of each size at McMaster or MSC, I found this vendor on eBay that sells assortments.   I should find what I need in this lot for $8.

(https://pbase.com/kvom/image/170378986/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on February 03, 2020, 10:57:02 PM
Great progress   :ThumbsUp: and I think your idea of building up a cylinder casting is sound.

You might Want to test the balls you purchased because if they are hardened you canít drill them.  I looked hard and found a vendor that sell brass ones Iíll use on my model.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on February 04, 2020, 07:12:30 AM
The stainless steel balls are usually drillable and look like steel ones if those prove to be too hard. Heating will often soften the hard ones enough to work them though you may want to Loctite them on rather than risk a tap.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 04, 2020, 07:08:44 PM
The test steel ball (used a 17/32" diameter) was hardened, and my attempt at spot drilling it came out bad for the drill.   :'(

I ground off a bit to see if it was perhaps only hard for a thin coating, but that was not to be.

Finally heated it red-hot with a torch and allowed to cool.  This led to being drillable, albeit slowly, with a .104" drill.

(https://pbase.com/kvom/image/170384408/large.jpg)

Fly balls are .625" diameter so very thorough heating is likely needed.  The challenge of drilling a separate hole perpendicular to the first has yet to be addressed.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: cnr6400 on February 04, 2020, 07:27:38 PM
Hi Kvom, if you have a mill vise with a V groove across one jaw horizontally, the perpendicular hole is easy to do. Just place a rod a close fit in the drilled existing hole, then place the rod in the vise V groove with ball face touching the vise. Zero up on the outer side of the ball in line with the rod, and move as far as you need to across the ball to drill the perp hole. Remove the ball, loctite the rod in the existing hole in ball, wait for loctite to cure, then drill the perp hole. Re-Heat to release the loctite and remove the rod. Hope this helps.  :cheers:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on February 04, 2020, 08:31:41 PM
Hold in a collet block with say 40% of the ball sticking out of the collet.

Mount block at 45degrees in the mill vice and drill first hole then hold at 45deg the other way to drill the second which will put the two holes at 90deg to each other.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 05, 2020, 01:05:25 AM
Jason's idea is clever.  I'll have to see if the collet will actually hold a ball.  One of the holes is a through hole for the pivot arms, and the other is partial penetration for the rod connecting to the collar.  I definitely don't want to drill into the interior of the collet when doing the through hole.

My own idea, after last post, was to clamp the ball in the machinist vise near to the edge of the jaws.  Drill the through hole, then  turn the vise 90 degrees for the partial hole.

In the meantime I competed the governor cutoff counter weight, which plays a large role in setting the engine's speed.

(https://pbase.com/kvom/image/170385123/large.jpg)

The weight at the Warwick RI museum appeared to be several discs on a rod, so the grooves give the idea of that.  As can be seen in the photo, the weight wants to turn the lever counter clockwise and thus apply a downward force on the governor top. 

As the balls spin and rise, the centripetal force applied to the collar will cause the top to rise as long as it's greater than the weight of the top and the force applied by the weight.  Once the two forces balance, the speed is determined.  There is some addition resistance from friction in the cutoff mechanism connected to the bottom of the lever, but that's assumed to be minor.

So it can be seen that adjusting the counterweight will affect the total force applied against the fly ball force.  Increase the weight and the engine slows, decrease and it speeds up.  Small adjustments can be made by sliding the shaft of the weight in and out.

Slowing the engine means the top lowers pushing the cutoff rod on the lever toward the cylinder.  This in turn raises the trips causing the valves to remain open longer.  The additional steam power then acts to speed the engine up.

The system provides a safety against a runaway engine in that if the speed is too high the trips will be lowered such that the catches miss the trip entirely.  The dash pots then pull the inlet valves closed.

I suppose that each factory powered by one of these engines had an optimal speed to drive the equipment, and that the engine was set for that speed.  Then the optimal cutoff setting could be set by adjusting the length of the cutoff rod so that the trips are at the desired height at speed.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on February 05, 2020, 07:04:14 AM
I've held balls in the lathe 5C collet to drill and turn them so should be OK. If you need a bit of clearance for the through hole the two angles could be altered so long as they add up to 90deg.

Your last photo prompted another thought and that would be to place the ball onto the corner hole of a 123 block and clamp in position. then you can use the edges of the block to give your 90degree positions. May be a little harder finding ctr of the ball.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 05, 2020, 12:49:01 PM
I went to the website of the ball supplier, and it seems that there's a mixture of hard chrome and softer carbon steel balls in the assortment.  Might get lucky with the 4 I need.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on February 05, 2020, 10:48:27 PM
McMaster Carr sells low carbon machinable balls.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 06, 2020, 02:05:15 AM
The problem with McMaster is having to buy a large quantity to get the 1 or 2 that I need.   :thinking:

I found that the ball assortment bag had a lot of odd sizes.  I did find a 5/16 for the exhaust ball joint.  It's hard so I'll try the annealing approach.

On the good side, I realized I had a small bag of brass 5/8" balls that I used for another governor.  While I did find that I could hold them in the 5C collet, it was a lot easier with the 6-jaw chuck.  I drilled the center through hole .101", and then found this method of lining up for the cross hole:

(https://pbase.com/kvom/image/170390035/large.jpg)

With the chuck on the bench, a length of drill rod through the hole keeps the ball from falling through.  Then I used two parallels under the drill rod to level the ball before tightening the jaws.  Then back to the lathe to drill .078" halfway through and thread 3-48.

(https://pbase.com/kvom/image/170390036/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 07, 2020, 01:29:44 AM
Spent a bit of time in the shop making the simple lower flyball supports.  Essentially a .3" diameter disc with a center .126" hole and a threaded 3-48 hole into the perimeter.  A length of threaded rod connects a flyball, and the disc is attached to the collar.

(https://pbase.com/kvom/image/170392754/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: jeff l on February 07, 2020, 02:46:16 PM
looks like i'll supply the machinable balls to help the builder .
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on February 07, 2020, 03:23:37 PM
Good progress Kirk,  its the little stuff that makes a model look exceptional.  Also, thanks for the notes to improve the drawings.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 09, 2020, 12:23:18 AM
I annealed a 5/16" ball allowing me to through drill and tap 3-48.  Now I need to make the cage for the ball joint, which entails drilling two 5/16 hemispherical holes that together will hold the ball captive.  I do have a 5/16" ball mill, so I did some experiments in a piece of 6061 AL.

I touched the mill to the material and used a spindle stop to mark.  Then raised the table 5/32.   I found that the mill likes slower RPMs.  To get smooth finish I used a spotting drill to 5/32 depth to remove pressure on the center of the endmill.  In any case, I did get a smooth hole, but it wasn't deep enough to descend the ball halfway.  Tomorrow I'll experiment with setting the depth control deeper.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on February 09, 2020, 06:59:06 AM
Can you not 3D mill it with say a 1/4" cutter, I've done male hemispheres so female would be a similar job.

(https://www.model-engineer.co.uk/sites/7/images/member_albums/44290/829660.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 09, 2020, 12:58:29 PM
That's certainly an option if the straight drilling doesn't work.

On another front, I was looking online for the necessary bevel gear and pinion needed for the gearbox.  Plans specify Boston Gear G478Y.  Google search didn't show any sellers on Amazon or eBay, and via a distributor they are pricey.  But I did find a close substitute that's quite reasonable.  SDP/SI has the pinion at $13.89 and the gear at $16.58.  I was able to download step files for both these and the BG version, and they are practically identical in size, and fit the governor model.  Both gear sets are 2:1, but the SDP/SI are 36/18 teeth while BG is 40/20.

Gear: http://shop.sdp-si.com/catalog/product/?id=A_1B_3-Y48036
Pinion: http://shop.sdp-si.com/catalog/product/?id=A_1B_3-Y48018
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 10, 2020, 09:13:08 PM
After some dimension discussion with Dennis about some clearance,  I decided to make a start on the center shaft of the governor as designed, which is shown here:

(https://pbase.com/kvom/image/170409084/medium.jpg)

The top 5/16" diameter ball attaches to the upper fly ball links via an axis pin through the cross hole.  The axis goes through the upper section, and the top .25" diameter section rests on the top section where the hole narrows to 3/16".  The bottom of the shaft is where the gear pinion is attached.  While there are nominal lengths for each section I will wait to obtain the gear before finishing.

I had several ideas for attaching a ball to the shaft, but came up with the following.  With some 1/4" drill rod in the lathe, I used a 5/16" ball endmill in the tailstock to slowly drill a pocket in the end of the rod.  I then drilled and reamed a 1/8" hole in the center of the pocket about 1/8" deep.  After annealing the ball with a Mapp torch, I mounted it on the lathe and drilled/reamed a 1/8" hole 3/16" deep.  I then cut a piece of 1/8" drill rod and trimmed to measure to attach the ball to the end of the rod as a type of tenon.  I then liberally applied 638 loctite to assemble the three pieces.  My theory is that this way there is good surface area for the loctite, and the .104" cross hole won't cut the pin completely.

(https://pbase.com/kvom/image/170409082/large.jpg)

(https://pbase.com/kvom/image/170409083/large.jpg)

After it cures overnight, I'll drill the cross hole.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 14, 2020, 07:32:23 PM
Continuing with the center shaft, I cross drilled the ball, and then turned in the lathe using 200-grit sandpaper to remove most of the black surface of the ball.  Then it was time to trim the shaft to the proper length.  The lengths of individual sections of the shaft have nominal lengths, but since the top part may vary from the drawing, I decided to use the SW model to determine the distance from the top of the top to the cross holes' centerline.  This is .541".

(https://pbase.com/kvom/image/170425254/large.jpg)

Given this, the bottom of the 1/4" section should be even with the bottom of the top section.  I marked this point and parted off, then drilled and reamed a .186" hole 5/16" deep.  The 5/16" section is to be loctited into the end.  The length of this section is then determined by the bottom edge of the bottom section.  Again this length is marked and parted off, and the end is drilled and reamed .126" 1/4" deep.

(https://pbase.com/kvom/image/170425255/large.jpg)

The 1/8" section to be glued to the end will have the pinion gear mounted.  While the SW model shows a fixed length section plus a final threaded section for a nut, the gear will be held in place by a 3-48 grub screw.  The section will be long enough to allow the position of the gear to be varied vertically to mate with the large gear.

I received the gear set.  Both had to be reamed to slide smoothly onto their axes.

(https://pbase.com/kvom/image/170425256/large.jpg)

(https://pbase.com/kvom/image/170425257/large.jpg)

(http://)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 15, 2020, 02:12:41 AM
To connect the two lower parts of the governor body, a circular pocket is machined into the gearbox.

(https://pbase.com/kvom/image/170426570/large.jpg)

Good fit.   :)

(https://pbase.com/kvom/image/170426571/large.jpg)

The 4 pieces all together in position for the first time.

(https://pbase.com/kvom/image/170426572/large.jpg)

In order to proceed further, I need the last two pieces, the upper ball arms.  These are tricky parts, and after considering many ways of making them I think I finally have a good sequence of ops.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 16, 2020, 09:43:32 PM
Having drilled the bosses of the gears for set screws, I installed the large gear into the gearbox to have the reality of the situation made clear:

(https://pbase.com/kvom/image/170432643/large.jpg)

The top of the bevel is closer to the flat milled for the bottom of the center section, and the length of the gear's boss means the bevel is too close to the center.  This means that the boss length needs to be shortened to move the gear teeth away from center enough to mesh the with the pinion.  I can also see that I need to drill a hole in the flat somewith larger than the pinion to allow  it to engage the large gear.

Then too, the bottom of the center section needs a hole at least larger than the boss of the pinion, and the pinion will extent up into the section's body.  This the center shaft will need to be shortened to match.

(https://pbase.com/kvom/image/170432644/large.jpg)

This then implies that the setscrews for attaching the pinion may not be accessible via the gear box opening.  I need to model this anew to determine how to proceed.  But that will have to wait as I am off on a 3 week trip on Wednesday and won't be back at it until mid-March.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: sco on February 16, 2020, 09:54:10 PM
Make a new boss and Loctite it to the other side of the gear?

Simon.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on February 17, 2020, 07:10:35 AM
If you put the large gear on the other way round you will then be able to access the small gears grub screw to fix it to th eshaft and then slide the larger gear already fitted to its shaft into place and screw on the side cover.

Or put a hole in the bottom for access and slide the vertical shaft complete with small gear in from below if you want to keep the larger gear that way round

What did the original drawings show?
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 17, 2020, 12:40:06 PM
If you put the large gear on the other way round you will then be able to access the small gears grub screw to fix it to th eshaft and then slide the larger gear already fitted to its shaft into place and screw on the side cover.

Or put a hole in the bottom for access and slide the vertical shaft complete with small gear in from below if you want to keep the larger gear that way round

What did the original drawings show?

The large gear would normally go the other way;  I just tried it this way to see if there is more spaced to play with.

The boss on the gear is .20" long.  I could remove half of it and leave room for grub screws.  If that's not enough I can mill a pocket on the inside of the cover to get a bit more.  Simon's idea would work well too if the other options don't.

Even with the cover and gear removed it's not clear if I'd have access to the grub screws for the pinion if they need to be high inside the center section.  The drawings show the pinion secured by a threaded section at the bottom of the shaft, but that means it's not adjustable vertically.  The SW model doesn't show the gears at all.  A solution I'm pondering would have the upper section removable so that the pinion could be accessed.  I'll have to see once I modify the center section.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on February 17, 2020, 08:02:01 PM
I had some more time to play with this.  First I drilled the top with a .47" hole to allow the pinion to enter the case.  Then bored a 1/2" hole .150" deep into the inner side of the cover, which is .21" thick.  Now I could adjust the position of the large gear in and out.  Using the pinion on a piece of drill rod centering with the  Mark IA precision eyeball, I got the large gear pretty close to where it needs to be.

It seems that all I needed with the cover was a hole half as deep.  So now to retain the gear shaft I'll need a bushing on the shaft between the gear and the cover.  Or else remake the cover.  It seems I could have removed .075" of the boss with the same result.

With the gears meshed, the teeth of the pinion are all inside the lower box, but the boss will be inside the center section.  The grub screws won't be visible from the bottom case.  Therefore I'll drill the center section 1/2" to allow the main shaft to be inserted and removed with the pinion attached.  The position of the pinion will be able to be determined before the center and lower sections are attached permanently.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on March 21, 2020, 09:46:02 PM
Back to work after some weeks away from home.  Today's target is the upper flyball arms that connects the flyballs to the top of the shaft.  It's basically two Us that surround the balls with a shaft between them.  The "tricky" part is that the upper and lower Us are offset from each other so that at the top they interlink but keep the shafts and lower U centered.  I imagined multiple ways to make these, so this is one possibility that if it fails I have other ideas.

I decided this was a good time to dust off my surface grinder that has been asleep for a couple of years.  After slicing off a a chunk of 2" diameter steel (I "think" it's stressproof), I faced both ends and then ground them as well.

(https://pbase.com/kvom/image/170538796/large.jpg)

I then turned on end down to 1.125" diameter for a length of .25" allowing the work to be held in a collet block.  Here's the setup on the CNC mill.

(https://pbase.com/kvom/image/170538797/large.jpg)

The Us were machined .25" deep (finished part is .19" thick).  The bars to the side will be used to accurately clamp the part in a mill vise later on.  Doing it this way means that the Us are the correct distance apart and offset correctly.

(https://pbase.com/kvom/image/170538798/large.jpg)

On the Bridgeport, .099" holes are drilled for the shaft.

(https://pbase.com/kvom/image/170538799/large.jpg)

A length of .097" drill rod is loctited for the shaft, and the Us are connected to the side bars with some CrystalBond, an adhesive with a melting point lower than boiling water.  Left overnight for curing.  Next a slice will be cut off on the lathe leaving a thin portion of the bottom, and this will be milled off until the part is free.  I'll then boil off the bond and bring to final thickness with the grinder.

(https://pbase.com/kvom/image/170538800/large.jpg)

The puck will be faced and ground again for the second one.  I'll need to drill cross holes on both Us for the mounting pins.  Because the space  between the interlocked top Us will be tight, I expect some fettling will be in order.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Johnmcc69 on March 21, 2020, 11:11:26 PM
Pretty slick way of doing that!

 John
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on March 23, 2020, 07:50:46 AM
This attempt ran into a few glitches, mainly in separating the parts from the workpiece.   :-[ The Crystal Bond isn't stout enough to hold and I messed things up a bit.  Then the drive wire on my grinder came loose and I spent all afternoon figuring how to fix that.  :hammerbash: While I can probably recover this try, I now have better ideas on doing the next and may just make two more instead.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 01, 2020, 10:35:17 PM
Since the last post, I had some equipment issues to distract from progress.  First the X axis drive cable on my surface grinder came loose, and given that it had some decades of wear and some kinks, getting it back in place was frustrating.  Finally I took a look on youtube, and decided to order a replacement cable from McMaster.  Just got it today.  Bigger issue was my lathe quit working, and it took several days and assistance from the Monarch guys on Practical Machinist to get it going again.

Back on the engine, I started the third time to make the upper flyball arms.  For this trial, the bar holding the two ends would be 3-48 threaded rod, since loctite apparently isn't strong enough for tiny parts with little surface area.  Here, all 4 "Us" could be milled on the end of the 2" rod.  Note that the ends are all aligned and at the same distance from the center.

(https://pbase.com/kvom/image/170574122/large.jpg)

By doing this, I could use all 4 sides of the collet block for drilling, and with a vise stop in place the X value needn't change between moves of the block.

(https://pbase.com/kvom/image/170574122/large.jpg)

(https://pbase.com/kvom/image/170574124/large.jpg)

(https://pbase.com/kvom/image/170574125/large.jpg)

After parting off and freeing from the remaining material, each was brought to final thickness individually.

(https://pbase.com/kvom/image/170574126/large.jpg)

Initial test showing how the offset to the small end allows the connecting shafts to line up.

(https://pbase.com/kvom/image/170574127/large.jpg)

The small ends need some filing to make room for the ball on the center shaft.  To cover the threaded rods, I took 1/8" drill rod and drilled it with a .099" drill making a tube.  The two ends are then screwed down to touch the tube.  The same was done on the two lower ball arms.

(https://pbase.com/kvom/image/170574128/large.jpg)

Finally a test fit to the governor "family".

(https://pbase.com/kvom/image/170574129/large.jpg)

Now I need to make some pins to hold it together properly.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 05, 2020, 05:00:58 PM
While waiting for some deliveries, I spent a couple of days working on the cylinder head assembly.  This consists of three close-fitting parts: the cylinder head, packing insert, and packing nut.

(https://pbase.com/kvom/image/170586685/large.jpg)

The cylinder head was turned from a piece of 2.5" round grey cast iron rod left over from another project.  While the turning and boring were straightforward, parting off was not.  With my 1/4" parting tool needing to stick out 1.25", it chattered so badly I wasn't able to find an rpm that was tolerable.  Because the work was only 4" long, I couldn't fix in my bandsaw vise firmly enough to saw through, and I certainly had no intention of hacksawing that thickness.  I ended up being able to clamp it securely in the Bridgeport's vise and milling halfway through with a 5/16" endmill, 50 thou per pass.  Then turned over to repeat.   :headscratch:

After doing this, it occurred to me that an easier way would be to mount my CNC 4th axis and mill downward as it turned, in essence milling a spiral slot.  Of course I'd need to vary the Z axis feedrate to maintain a constant SFM.  I may write a Java program to generate the g-code as an exercise.

The other two parts are bronze.  The insert was just the right size for a piece I had laying in a drawer, and the nut was from a length of 1" rod.

After drilling and tapping, here are three assembled.

(https://pbase.com/kvom/image/170586686/large.jpg)

Note that the "nut" isn't a classical threaded packing nut, but id instead tightened by the two screws.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 06, 2020, 01:21:15 AM
I have been nibbling away at the crosshead guide (called frame in the plans) casting.  You can see the raw casting in this photo I posted on page 1.

(https://pbase.com/kvom/image/169134021/large.jpg)

This piece presents quite a few challenges, both from its size and also from the many surfaces that will need to be aligned just so.  To start, I felt that the edges of the side opening were the flattest and straightest. so I was able to mill parallel faces in two dimensions.  Here I've milled off the large sprue from the cylinder end.  1.5" removed 50 thou at a time with the side flutes of a 1/2" 4 flute endmill.

(https://pbase.com/kvom/image/170587716/large.jpg)

After today's efforts I have this:

(https://pbase.com/kvom/image/170587717/large.jpg)

The initial reference surfaces, red arrows are flat and parallel to each other and the two surfaces indicated by the  yellow arrows.  The sprues on each end, green arrows, are parallel.  Now I need to find the centerpoint on each end that will be the centerline of the piston rod.  The blue arrow shows the center of the cast angle where the slippers on the crosshead will ride.  So I'd like to set the vertical coordinate of the center point as close as possible to that line.  The other coordinate could be guessed via eyeballing the part lines, but since there's another cast angle on the opposite side, I intend to split the difference between them.

Before quitting for the night I slid my milling vise over and aligned the work on the mill table.  Using a pair of ground rods designed to fit Bridgeport slots closely, I used the 2-3-5 block against them and the cylinder end surface I had just machined to align the casting.

(https://pbase.com/kvom/image/170587718/large.jpg)

Once I can determine the center dimensions, I'll need to drill both ends with a center drill so I can mount between centers on the lathe and eventually an indexing head.  Here's where one of those right angle drilling attachments would come in handy, but alas, I lack one.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on April 06, 2020, 02:26:20 PM
Looking really good Kirk. 

Tony has his completed, but I wonít get over to his place for a while to see if he has it running.  When I last talked he was thinking the valve adjustments could be tedious.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 06, 2020, 09:26:54 PM
Since you can't see the exhaust valves, they could be hard to adjust.

If you go to see it run, please take some pics/video.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 07, 2020, 04:31:15 PM
To determine the 3rd plane as the centerline of the crosshead, I made this "tool" quickly from some aluminum.

(https://pbase.com/kvom/image/170593793/large.jpg)

Then I touched it lightly to the inside crease on both sides, and used the DRO to divide the difference.

(https://pbase.com/kvom/image/170593794/large.jpg)

Then I used a height gauge to measure the distance above the table.

(https://pbase.com/kvom/image/170593795/large.jpg)

This is the distance to the center measured from the two "feet" supporting the casting.  After milling faces on the sprue equidistant from the center, I did the same on the cylinder head side both for clamping and for center finding.

(https://pbase.com/kvom/image/170593796/large.jpg)

Clamping the casting vertically on the sprue, I was able to verify that the cylinder side is flat.  Don't try this on a mini-mill.

(https://pbase.com/kvom/image/170593797/large.jpg)

Center drilling.  The other side was done similarly.

(https://pbase.com/kvom/image/170593798/large.jpg)

Test mount on the lathe between centers.  I didn't as yet remachine the chuck's center, and I also need to fabricate something to clamp onto the sprue to act as a lathe dog.  The only turning will be on the round boss at the tailstock end.  This boss will then serve for chucking on my 4th axis rotary table chuck for machining the guide V's.

(https://pbase.com/kvom/image/170593799/large.jpg)

I still foresee some issues.  While the clamping was sufficient for center drilling, there was a bit of vibration.  When it comes time to open up the cylinder end I'll need something more rigid.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 07, 2020, 09:33:37 PM
I decided that a rod inserted into the sprue would be effective as a lathe dog given how it lined up with the vise jaws.  I tried this setup in order to drill a 1/4" hole 3/4" deep.  It was quite rigid.

(https://pbase.com/kvom/image/170594631/large.jpg)

Cut some drill rod just the right length.

(https://pbase.com/kvom/image/170594632/large.jpg)

I ran the lathe at 450 rpm and took very thin cuts of 20 thou.

(https://pbase.com/kvom/image/170594633/large.jpg)

The setup to make further progress on this will take me a while, so I'm going to put further work on it aside for now.  There are some small parts I need to make that I "skipped over", and I want to finish the governor.  I can also start preliminary work on the crosshead casting.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 09, 2020, 10:26:31 PM
Moving on to the crosshead, I decided that the casting provided would take more work than machining it from bar stock.  I had a piece of 2.5" diameter round rod .9" thick that was a good match for the crosshead size (which is .75" thick).  Here's a picture of the crosshead from Solidworks.

(https://pbase.com/kvom/image/170605083/medium.jpg)

This design is different from all my previous engines where the piston rod screws into the crosshead and is fixed with a jam nut.  Here the piston rod is clamped by the action of two screws and the horizontal slit.  There will be a separate round boss added at assembly;  were it left on the stock  there was insufficient room for an endmill to profile it.

To start, I machined a pair of soft jaws to hold the iron disc securely. 

(https://pbase.com/kvom/image/170605066/large.jpg)

The profile was roughed out with a 1/2" endmill and finished with a 1/4".  I took some deeper cuts that I have in the past (.25" DOC x .2") and as a result I had the endmill pushed into the collet by 40 thou at the end.  That's a problem witn carbide cutters and R8 collets.

(https://pbase.com/kvom/image/170605067/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on April 09, 2020, 10:57:17 PM
Interesting crosshead design, never seen that before. I wonder if the mating surfaces should be left a little rough for a good grip.


 :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 09, 2020, 11:02:43 PM
Finishing passes with 1/4 and 1/8 endmills.

(https://pbase.com/kvom/image/170605068/large.jpg)

To remove the remainder of the rod I milled a half inch from each side followed by using the side flutes for the rest.

(https://pbase.com/kvom/image/170605069/large.jpg)

(https://pbase.com/kvom/image/170605070/large.jpg)

The reverse side is milled similarly but has a small integral boss, as this side will be tapped for the cross pin.

(https://pbase.com/kvom/image/170605071/large.jpg)

The conrod end is hollowed out: 1x3/8 by 1.1 inches deep.  I made it a couple of thou wider to give the conrod end some room.

(https://pbase.com/kvom/image/170605072/large.jpg)

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 09, 2020, 11:03:48 PM
Interesting crosshead design, never seen that before. I wonder if the mating surfaces should be left a little rough for a good grip.

The"hole"  to be drilled is shown as two .166" radii separated by a 1/16" slit.  So it appears that clamping may spread the sides of the two half holes to increase the mating surface.  But the instructions say to machine to a close fit to the 3/8" rod.  The .166 radius doesn't make a lot of sense

I bought a collection of new-looking slitting saws at Cabin Fever, and have a 1" arbor on order from ebay in order to mill the 3 slits.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 10, 2020, 10:48:36 PM
I drilled the holes for the conrod crosspin.  The outside side is 5/16 and the inside is drilled and tapped 1/4-28.  I then drilled the hole for the piston rod.  I decided that as drawn it didn't make sense, so I reamed .374.  When the cross slit is done, I'm assuming the .375 rod can be inserted without too much drama.  Since it needs to be fairly  precisely positioned to account for the movement of the conroad and the piston.

The cross pin itself is a piece of 5/16 drill rod, drilled and tapped 1/4-28 on one end and 3-48 on the other.  While the plans show the 1/4 threads as one piece with the rod, I cut off a screw to provide the short threaded rod.  The pin is inserted on the front side and screwed into the tapped hole on the other.  To prevent it from  coming undone, a retaining cap is show in the plans; this sits over the outside end and is attached with a screw or stud.

(https://pbase.com/kvom/image/170607825/large.jpg)

(https://pbase.com/kvom/image/170607826/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 11, 2020, 10:06:18 PM
More work on the crosshead today.  After drilling the holes for the clamping screws, I milled the top and bottom slots on the Bridgeport using a 1/8" endmill and .025" DOC each pass.  Quite tedious. 

The center slit I had intended to do with a slitting saw, since my eBay arbor came in the mail today.  Alas, it seems that the saw I was going to use (2.75" diameter, .06" thick, 80 teeth) wants to rotate at no more than 100 rpm, according to G-Wizard.  The Bridgeport  VFD doesn't like to spin that slow for long, and the back gear is inoperative.  I measured the depth to cut on each side as .2", so went about it on the CNC mill with a 1/6" endmill which had flutes just long enough. 

I was able to insert some 3/8" drill rod into the opening with some difficulty.  Spinning the end in the lathe with some 500 grit sandpaper made it possible to go in a bit further by hand, and difficult to remove the same way.  The SW model shows only a small length of the piston rod in the crosshead.

(https://pbase.com/kvom/image/170610648/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on April 11, 2020, 10:14:04 PM
Pretty work.  :ThumbsUp:

Following along.  :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 14, 2020, 08:06:50 PM
Thanks for checking in, Craig.

Last two shop sessions were for commencing the conrod.  The dimensions allowed for making from 3/4" round stock, so I cut a 9" length of drill rod.  A center drill was used in both ends for later turning the shaft.  Holding in a collet block and using a vise stop allowed for rough machining each of the 4 sides of the ends in turn.  This is the crank end.

(https://pbase.com/kvom/image/170620067/large.jpg)

And the crosshead end:

(https://pbase.com/kvom/image/170620068/large.jpg)

Turning the center shaft proved troublesome.  With one end in a collet chuck and the other on a live center, I got a lot of chatter and vibration.  I think a lot of it can be attributed to the large through pocket.  If I were to do this again, I'd hold off on machining it as long as possible.  What eventually worked best was to clamp a bit less than half the shaft in my 6-jaw chuck (the ends were further inside the chuck than the jaws) and turn the other half towards the tailstock.  My only left-handed turning tool used HSS inserts and dis a reasonable job, but this material has a tendency to tear and not provide a fine finish.

(https://pbase.com/kvom/image/170620069/large.jpg)

Next I took each of 8 sides of the ends to spec one at a time using the side flutes of an endmill.  This  leaves the center holes intact if I need to do more turning.

(https://pbase.com/kvom/image/170620070/large.jpg)

The conrod as it stands now.  I needed to reduce the width of the crosshead end by .002" to get a nice fit.  At some point the remainder of the ends needs to be milled away, but I want to try polishing the center shaft on the lathe a bit more.  Plans call for a 1.2 degree taper from the center to the ends, but I may not attempt this as getting a decent finish with the hand-fed compound is rare.

(https://pbase.com/kvom/image/170620071/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: scc on April 14, 2020, 10:53:35 PM
Nice work...... :popcorn: :popcorn:      Terry
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 16, 2020, 12:56:51 AM
Thanks for visiting Terry.

Today I made the end strap for the crank end of the conrod.  This c-shaped piece fits over the end of the conrod, and the crank pin bearings live in the space provided.  Through slots in the strap and conrod allow for tapered wedges to press the split bearing together.

I started with some 2" steel rod from which I cut off a 1" length.  After facing both sides, I turned one side down to a 1" diameter for a length of 1/2".  This allowed holding the work in a 5C collet block that was mounted on the CNC mill.  The roughing was done as 3 trochoidal pockets with a .01" roughing allowance.  Normally I haven't done many pockets deeper than the tool diameter at full depth, but this time G-Wizard said I could safely machine 3/8" deep with a 1/4" carbide 3-flute endmill.  Stepover was .025" at 4000 rpm and 5 ipm.  I could actually have done 7 ipm, but I remained a bit conservative.

First finish pass with the same endmill and 5 thou allowance was followed by final finish with a 1/8" endmill just to reduce the inside corner diameter.

(https://pbase.com/kvom/image/170623386/large.jpg)

After machining away the unneeded remainder of mater on the Bridgeport, I was happy to see a decent fit over the conrod end.

(https://pbase.com/kvom/image/170623387/large.jpg)

Then back to the CNC mill to machine the 0.1x0.6" slots in each arm, using a 5/64 endmill.

(https://pbase.com/kvom/image/170623388/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on April 16, 2020, 01:28:23 AM
This is A very demanding model, and youíre doing a remarkable job with it.  Iím following along.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 16, 2020, 02:21:02 AM
if you include studs/screws/nuts Solidworks says 491 parts.   :o
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 19, 2020, 08:48:34 PM
For the crank end, I need to make two wedges that fit through the slots cut in both the end strap and the conrod.  Pressure from the wedges will draw the end strap onto the conrod;  however, once the two slots are aligned , no more motion can occur.  According to the SW model, there should be 12 thou of allowed motion to press the bearing tightly between strap and the end of the conrod; unfortunately it appears I was off a bit and will need a shim.   :'(

In the meantime, I also made the two pieces for the crosshead bearing.  Here, the bearings are flush with the edge of the rod, and pressure to retain it is provided my two wedges that are expanded by a screw.  A "press block" sits between the inner wedge and the bearing.  Both wedges are the same.  Here I machine the profile in some 7/16" brass rod.

(https://pbase.com/kvom/image/170635598/large.jpg)

Over at the Bridgeport, the .149" through hole is drilled, and then the piece is parted on the lathe.

(https://pbase.com/kvom/image/170635599/large.jpg)

Then back to the Bridgeport to remove the nub left from parting and bring to the correct length.

(https://pbase.com/kvom/image/170635600/large.jpg)

With the wedges in place connected by a 3-48 screw, the size of the press block can be determined.  The plans specify .350", but I used to gauge blocks to get .355.

(https://pbase.com/kvom/image/170635601/large.jpg)

I still need to shorten the end of the conrod to fit the crosshead and to make the press block.  Then I can drill the bearing 5/16".

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: scc on April 19, 2020, 08:57:19 PM
Nice work :ThumbsUp: :ThumbsUp:   It looks vaguely similar to the rod end on my Charlsworth engine. (reply 19)    Regards   Terry
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 20, 2020, 01:59:02 AM
I looked at yours. which seems closer to those on my Joy engine, where a vertical screw tightens the wedge.  In the Greene case, the bearings will be completely inside the cavity of the crosshead, but the wedges won't.    Many ways to do the same thing.  I'll need to trim the bearing halves as they are slightly proud of the conroed end.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on April 20, 2020, 02:09:32 PM
Good progress Kirk.  I was looking forward to talking about the Green engine with you at NAMES next weekend, but maybe we can watch your engine run at NAMES next year. 

The Green Engine is a challenging engine to build and we tried to stay close to the original design in spite of the challenges that caused to model engineers.  John and I worked together on 5 engines and each was closer to the original design than the one before.  A challenge we both enjoyed working through.  As John and I worked through the design and building of the first Green model, a lot of changes were made to help with clamping and holding parts.  John was good at figuring out how to build the difficult parts and what could be done to make the work easier.  John died last week from the corona virus but his contribution to the Green engine, and several other models we developed will last for a long time to come.

Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 20, 2020, 08:15:33 PM
That's very sad news, Dennis.  I never met John but did see the Greene running at NAMES one year;  I think you said it wasn't quite finished at that time.  I do have the video of it running, of course.   

Whether I finish mine by next year will depend on how much shop time I spend;  the social distancing at the moment has meant more time working on it.  I'm still waiting to get the replacement cylinder block casting, but Jeff said I should be able to get it soon.

As for today's session, I machined the spacer block for the conrod, shortened the crosshead end of the rod, shaved the bearing blocks to stay within the rod's width, and put it all together.  Then a trial fit into the crosshead revealed that the split line for the bearing wasn't visible through the cross hole.  Some measurement showed that the bearing blocks were too wide by 23 thou.  Shaving these down to the .256 width indicated by the SW model allowed the line to be seen in the center of the hole, but now the press block was too narrow by 46 thou or so.  I need to remake this next time in the shop.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 23, 2020, 07:34:23 PM
It was time to revisit the crank disk, which I started in reply #48.  I did not go beyond cleaning up the reverse side and left the disk oversized.  Now that the conrod is close to being finished I wanted to complete the disk so as to be able to fit the conrod to it.  I mounted it to the lathe with a mandrel and faced the rear (bearing) side to bring the rim width to .500". 

I also turned the crank pin from some 3/4" drill rod.  This has a 5/16" section where the bearing ride, a 1/2" section that's pressed into the hole, and a 3/4" flange.  To get the 5/16 section to line up with the front, I needed to mill a counterbore to the hole on the read side to accommodate the flange.  Normally to hold a large disk on the mill I'd mill some soft jaws, but it occurred to me that the 4-jaw chuck with jaws reversed could hold it securely.  Note that all much D1-3 chucks will mount in the vise jaws when held with my D1-3 spindle nose I've used frequently before.   Heavy to lift into position but quicker than soft jaws.

(https://pbase.com/kvom/image/170647016/large.jpg)

The plans call for a press fit of the pin into the disk.  Measurement is fine, but you never know until pressure is applied.  Coated oth pieces with oil to help.  It turns out the arbor press did  fine until the last few thou, and a bench vise applied pressure to finish.

(https://pbase.com/kvom/image/170647017/large.jpg)

The end of the pin is tapped 3-48 for a retainer that prevents the conrod from sliding.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 25, 2020, 11:00:05 PM
The past two day's shop time was spent working on the slide valves and valve plates.  The valves are made of steel and still have one operation to go, but I did finish the plates on which the valves slide.  Here is a plate machined into the end of some 1.75" cast iron rod.

(https://pbase.com/kvom/image/170652922/large.jpg) 

The slots are 1/16" wide.  There is a plate and valve for each end of the cylinder and are located in a steam chest.  The valve slides in the 3/4" wide slot machined in the plate, and operates so that the slots are both open or both closed.  The reason for two slots is to increase the steam volume introduced at full load.  The 4 corner holes are for screws that attach the plate above a cavity that is open to the cylinder port.

After parting off at the lathe, I removed the stock left on the bottom of the plates, and then countersunk each of the mounting holes for 3-48 flat head screws.

(https://pbase.com/kvom/image/170652923/large.jpg)

To get consistent countersinks on the Bridgeport, I used a spindle stop to mark where the tool just touched the first hole edge.  Then a raised the table 10 thou at a time until a screw head was flush with the surface.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on April 25, 2020, 11:52:55 PM
Very interesting setup on the valves. Is the same arrangement on both the steam inlet and the exhaust valve?
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 26, 2020, 12:08:35 AM
The exhaust valves are different entirely.  Look at reply #89.  They are located below the cylinder on each end.  But again, the idea is to allow lots of volume with small valve movements.

Here's a pic showing how the valve and plate are in the cylinder block.  The other side shows the mounting position,
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on April 26, 2020, 12:18:59 AM
Clever design!    :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 26, 2020, 05:28:24 PM
This morning I finished the final operation on the valves, cutting the  .1" wide through slot.  Here CNC is an advantage as the mill can maintain a constant 3 ips feed rate for the 5/64" endmill.  I suspect manually doing this would take much longer gingerly turning the handwheel. 

(https://pbase.com/kvom/image/170655365/large.jpg)

(https://pbase.com/kvom/image/170655366/large.jpg)

On an unrelated note, I purchased this Shars MT2 live center at an estate sail a while back.  The screw that fits the end of the taper to provide the correct length for ejecting was too short and very loose, although the center itself is otherwise quite nice.  I determined that the thread is M10x1.5, and I found a suitable socket head screw at my neighborhood hardware store.  However the socket head diameter was too large and needed to be turned down to fit the tailstock taper.  Set at the correct length, the center can be removed from the tailstock much more freely as needed.  Worthwhile fix for the price of a $1.50 screw.

(https://pbase.com/kvom/image/170655367/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 26, 2020, 10:17:33 PM
One more out of the way.  A coupler between the two lengths of the exhaust actuator rod.  Simple turning job followed by drilling and tapping holes for 3-48 set screws.

(https://pbase.com/kvom/image/170656522/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 28, 2020, 12:19:16 AM
With the valves and plates done as well as most of the inlet mechanism, I thought it would be good to see it all assembled and see what problems there are in fitting.  The main missing piece is the cylinder block.  The new castings are available in principle at the foundry, but since the foundry is closed by the pandemic, there's no telling when I'll get one.

I considered making the top third of the block first from machinable wax and then from a piece of CI that I'd need to order, but then I thought why not machine the top part of the cylinder block already in hand.  The blown out part affects only where the air input line would attach.  After loading the DXF file of the top of the block into CamBam and setting all the machine operations, I simulated the machining at least a dozen times before being confident that it would come out OK.

After running the program (30 minutes aside from tool changes), I noticed one problem.  The as-cast outline of the two inlet pockets were too close to the center.  So I was left with this:

(https://pbase.com/kvom/image/170660922/large.jpg)

The rough cast edge on the inside of the pocket would cause a problem for the drill need to make the cross hole for the valve rod.  So I ran an addition operation to widen both pockets closer to the center by .1" for .3" DOC.  Now there's a smooth surface for the spotting drill.

(https://pbase.com/kvom/image/170660923/large.jpg)

From the top:

(https://pbase.com/kvom/image/170660924/large.jpg)

I tried fitting a valve plate but the fact that the drawing had 0 clearance planned means I need to take a few thou off the left and right sides of the plate.

I'm also going to mill off the area of the blowout to see the feasibility of replacing the removed material by a machined "plug".  That would save all the work of machining a new casting from scratch.  There are two chips on the edges of the block's bottom, but it's possible I might want to cover the sides with cover plates similar to the prototypes.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 30, 2020, 02:59:32 AM
Long shop day today, thanks to rain and coronavirus.   ::)

I milled the blown out area down to the bottom of the core, and as seen here it would be completely feasible to machine an oblong with a cross passage plus the vertical hole for the air supply.  That would leave the lower area of the defect to be covered, either by a cover plate or a second plug.  Extending the full cutout down far enough would intersect the cylinder bore, so that's out.

(https://pbase.com/kvom/image/170665774/large.jpg)

At this point, there's no reason other than esthetics why I can't make this one work.  So I continued and drilled all the remaining holes needed on both the top and bottom of the block.  That means 16 hole on top and 4 on the bottom that need tapping 3-48.

Next I needed to drill and read .126" holes for the valve rods.  To do this means drilling from the end faces through to the center pocket.  Eventually the outside holes will be plugged.

(https://pbase.com/kvom/image/170665775/large.jpg)

The good news is that I can look at one end and see all 4 holes nicely lined up.

(https://pbase.com/kvom/image/170665776/large.jpg)

I had drilled one of the holes where the exhaust valves live last year, no now it was time for the other.  There is a core in the casting for this, so I started with a 1/2" endmill to clean up the core hole, then a 15.5mm (.61") drill, and finally a .625" reamer.

(https://pbase.com/kvom/image/170665777/large.jpg)

(https://pbase.com/kvom/image/170665780/large.jpg)

One the reverse side I again had a chip at the end, but that will be concealed by the rear covers.

(https://pbase.com/kvom/image/170665778/large.jpg)

(https://pbase.com/kvom/image/170665779/large.jpg)

I then started to machine the casting for the cylinder head on the end opposite the crank.  This casting had a large sprue, and the drafts made it precarious to hold in the vise.  But I was able to securely mount it in the lathe's 6-jaw chuck.  Then the larger radius was "turned" using a parting tool to remove the draft.  This gave a good surface to clamp between two v-blocks to mill away the sprue.

(https://pbase.com/kvom/image/170665781/large.jpg)

(https://pbase.com/kvom/image/170665782/large.jpg)

Then I could go back to the lathe to face it to get a flat surface, then reverse to turn the smaller radius to match the cylinder's bore for a close fit.

(https://pbase.com/kvom/image/170665783/large.jpg)

Still work to do on this part, but my feet were hurting so time to shut down for the day.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on April 30, 2020, 03:04:41 AM
Great work saving that casting, some very complex shapes.  :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 30, 2020, 04:19:04 PM
A further machine operation on the block is to extent the cylinder admission ports down and into the exhaust valve holes.  This means a total DOC of close to 3".  I was able to source a 4" long carbide 1/4" endmill at carbidedepot.com for $23; it should be here by Saturday evening.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on April 30, 2020, 10:54:02 PM
Drilled the through holes for the cylinder head.

(https://pbase.com/kvom/image/170668115/large.jpg)

Similar on the block with a smaller drill (.079").

(https://pbase.com/kvom/image/170668116/large.jpg)

12 more holes to tap.   :(
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on April 30, 2020, 10:59:14 PM
Do you know what the purpose is for the extra bolt holes on either side of the cap, where they are more closely spaced? Is there something inside that is being held there?
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 01, 2020, 01:31:39 AM
Not extra bolts per se, just 4 groups of 3 with different spacing.  That's how they are at the NEWS museum engine.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on May 01, 2020, 07:52:33 AM
You often get ones like that, the "odd" pair are threaded to take jacking screws to make removing the cover and breaking the gasket's hold easier, put a couple on my Filler & Stowell. Also seen on valve chest covers, etc

Typical example here

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 01, 2020, 12:31:43 PM
That makes sense, although the "extras" look the same.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on May 01, 2020, 02:32:44 PM
Interesting Jason! Seems like the giveaway would be that those holes would be threaded in the lid with no holes in the block underneath. On some of the Marion engines I saw they cast in a notch around the edge to pry against.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 01, 2020, 09:07:45 PM
I got all of the holes tapped that need them thus far, but I also found a place where I screwed up.  When I drilled the bottom holes I used the center as the reference.  But 6 of them are for attaching the exhaust grid and needed to be centered on the exhaust holes.  They're far enough off that the screws won't thread, and close enough that I probably can't drill new ones separate from the bad ones.   >:(  They are .104" diameter.  So I quite for the day to come up with a fix.

One idea is to just widen the existing holes enough, and use a washer under the head of the screws.  The screw heads are concealed in a pocket in the feet that are then attached to the bottom.  This seems easier than the other alternatives I've considered.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on May 02, 2020, 03:57:11 PM
Hi everyone,
The uneven hole pattern on the cylinder heads on this engine is used to fool-proof the alignment of the cylinder head.  On the original engine, the piston travel ran up extremely close to the cylinder heads, I would guess this was to get as much of the expanded and cooled steam out of the cylinder as possible.  However with the piston nearly touching the cylinder head, the top and bottom of the cylinder head had to have a recess that would allow the steam into the cylinder to start pushing the piston.  A round cut was made across the top and bottom of the cylinder head and the hole pattern guaranteed that the steam passage in the cylinder head would always line up with the steam inlet and steam exhaust passages.  The Green Engine Model design does not include the steam passages in the cylinder head and the piston to cylinder head clearance is not very small because the engines will typically run on compressed air and at low speeds.  A  lot of the engines I have been fortunate enough to see original drawings on do have this feature.  It is good engineering to improve the performance of the engines AND to eliminate the possibility of the cylinder head being installed incorrectly.  If you encountered Pok-e-Oke fool-proofing programs in the 1970's and 1980's,  they were not the revolutionary new programs they purported to be, just a re-do of some very good 90 year old ideas with a new name to capture manufacturing' attention.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on May 02, 2020, 04:19:42 PM
Kirk,
I am glad to hear you have a way to save your cylinder block casting and all the time and effort you have put into machining it.  Your plan sounds like a good one.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 02, 2020, 11:05:55 PM
To redrill the mispositioned holes, I center find on a piece of 5/8" drill rod.

(https://pbase.com/kvom/image/170673403/large.jpg)

Drilling with a .104 drill failed as the drill drifted into the previous hole.  So I used a carbide endmill to drill without drifting.  The endmill is a few thou larger than the drill.  Afterwards I was able to fasten the lower grill in the exhaust hole using the new screw holes.

(https://pbase.com/kvom/image/170673402/large.jpg)

Afterwards I turned towards starting the piston and piston rod using a piece of 2" bronze rod that happened to be just about the length required.  After facing it ended up .011" short of the .800" plan length.  A through hole was drilled with a #3 drill, which is the tap drill size for a 1/4x28 thread.  A cavity .8" in diameter was bored .381" deep, slightly less than the plan depth of .400".  Then the remainder of the hole was tapped.

(https://pbase.com/kvom/image/170673404/large.jpg)

Finally the piece was reverse and a 1/4" endmill bored a short pocket for the end of the piston rod.

The rod itself is 3/8" in diameter, with the piston end turned down to 1/4" and threaded.  Once fastened together, they are secured by a nut in the pocket, and eventually loctite.  I need to make the rod next, and it will be fastened in the collet chuck to turn the piston diameter to fit the cylinder.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 03, 2020, 08:48:46 PM
Having received my 4" long .25" endmill yesterday, today I used it to mill the cylinder exhaust ports.  Basically this is just continuing the cuts of the admission ports down through to the exhaust valves' cross holes.

I decided to so this on the Bridgeport by doing chain drilling with a small overlap of holes.  Once the first cut wenth through I set a spindle stop for the rest.  After the chain was complete, I fed the endmill to finish the sides.

(https://pbase.com/kvom/image/170677143/large.jpg)

With the recent repair to my lathe, I am able to run it in reverse for the first time ever.  Since I need a 1/4x28 thread for the piston rod, I wanted to try single-pointing with spindle in reverse and tool upside down, feeding toward the tailstock.  I did a sample thread in some 1/4" drill rod, and I must say this is a lot easier than eyeballing when to disengage the half nut before crashing the tool.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on May 03, 2020, 10:55:00 PM
Kirk,
I remember some time ago for work doing some nonstandard thread. Once the handle was engaged I had to leave it engaged and run it forward to thread pull it out run it in reverse to back it to the beginning & repeat, as I recall there was some hand turning the chuck involved.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 04, 2020, 01:40:37 PM
Art,  I believe that is required when cutting a metric thread with an inch lead screw.  On my lathe you'd need some special gears. 

I have decided not to singlepoint the thread on the piston rod as there needs to be a section of 1/4" rod after the thread to fit in the pocket in the piston.  That pocket is only .2" long, and to single point the thread I'd need to cut a groove as a starting place for the tool.  To ensure good alignment with the piston I want to use the full depth of the pocket.

So thread mill it will be.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 05, 2020, 01:50:01 AM
To make the piston rod, I turned down one end of some 3/8" drill rod to a 1/3" diameter, then moved it to the CNN mill to thread mill the 1/4-28 threads.  I already had a CamBam setup for this thread, so the only work needed was changing the length of the thread.  I started conservatively with a .442 length. 

(https://pbase.com/kvom/image/170680979/large.jpg)

However, the piston blank would not screw on.  A  nut went on easily, so again a nut will attach where a tapped hole won't.  I changed the target minor diameter by .003, and that worked.  Now the blank would screw on, but not all the way down.

(https://pbase.com/kvom/image/170680980/large.jpg)

I used a feeler gauge to estimate the amount of additional thread needed, and eventually could get a tight fit against the rod.  Then over to the lathe to apply blue thread locker and cinch down both the blank and the nut.  This will sit until the next shop session where I'll turn it down to hopefully get a good fit to the cylinder bore.

(https://pbase.com/kvom/image/170680981/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 05, 2020, 11:04:39 PM
Turned down the piston blank carefully to get an excellent fit, around .001" according to measurements of both bore and piston.  Slides  nicely the full range.

(https://pbase.com/kvom/image/170683644/large.jpg)

I needed to drill the mounting holes around both sides of both exhaust passage holes.  The pattern relative to the holes' center is the same, so I was able to use a single g-code program for spotting and drilling the 4 holes.  I used the 5/8" drill rod in each hole to center find.  After doing the right side using G54 work offset, I switched to G55 for the left hole (manually entered the G54 and G55 commands).  The for the spotting drill set Z0, switch to the other offset and zero Z, the run the program to spot drill.  Switch offset again and rerun the program.  Mount the .079" tap drill, zero Z in both offsets, and then run again, once per offset.  The advantage here is reducing tool changes.

Turn the block over, do it all again.

(https://pbase.com/kvom/image/170683645/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 07, 2020, 09:07:48 PM
Today's project was to remake the catch housings that I attempted a good while ago.  I screwed up one of them and wasn't happy with the other.  Starting with some 1" diameter steel round, I faced it and mounted in the collet block.  Then the first CNC ops were drilling the holes for the catch and the set screws.

(https://pbase.com/kvom/image/170688132/large.jpg)

Finish was not great on the outside (3/16" carbide endmill at .9" DOC), but inside surface between the two was decent.

Then the block was turned 90 degrees to drill the hole for the valve rod and mill the profile.

(https://pbase.com/kvom/image/170688133/large.jpg)

Next, at the Bridgeport cut the two "steps".

(https://pbase.com/kvom/image/170688134/large.jpg)

While still in the collet block, tap the holes for the set screws.  The 3-48 tap is just long enough to do both ends of the through hole.

(https://pbase.com/kvom/image/170688135/large.jpg)

Then, cut off with a hacksaw and mill to final length.

(https://pbase.com/kvom/image/170688136/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on May 08, 2020, 08:42:26 PM
Coming along nicely Kirk  :ThumbsUp:

 :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 09, 2020, 12:20:36 AM
Thanks for checking in, Craig.

Today was time to start repairing the blowout section in the cylinder block.  On the Bridgeport, I used a 1/4" endmill and MarkI eyeball to cut out the lower abscess.

(https://pbase.com/kvom/image/170690962/large.jpg)

Not having any suitable cast iron raw material for a patch, I cut up one of the castings I didn't use and then reduced it gradually to about 5% of the original volume.  After getting the width, I developed a quick CNC solution to fillet the corners, and then gradually whittled down to a fit.

(https://pbase.com/kvom/image/170690963/large.jpg)

There should be plenty of surface area for Loctite to secure it.

The larger patch will be made from a piece of round.  To limit any possible air leakage I plan to more a cross passage rather than just a slot in the bottom.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on May 09, 2020, 12:53:53 AM
Nice save on the casting.




  But, you just had to talk about cutting out the abcess. Now I am flashing back to root canal work at the dentist!  At least once I had the pleasure of standing on the crypt of the guy who invented the dental chair during a tour of Westminster Abbey!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 09, 2020, 10:21:28 PM
Starting patch for the large opening in a piece of 1.8" CI rod.

(https://pbase.com/kvom/image/170693385/large.jpg)

After parting off, I nibbled to get a good fit with the width, then filleted.  Then gradual trim for height and depth leaving a few thou proud.

(https://pbase.com/kvom/image/170693386/large.jpg)

Next I drilled a 3/8" air passage across the width  to match the core, leaving enough on the top for a NPT tapped hole.  Finally applied Loctite to the bottom patch and clamped to await overnight cure.

(https://pbase.com/kvom/image/170693387/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on May 10, 2020, 02:41:46 AM
If I remember correctly, Tony said he had a void in  his casting that he filled with Jb weld.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 10, 2020, 02:45:44 AM
I don't think that would have worked here.   :ShakeHead:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on May 12, 2020, 02:30:42 PM
Iím not arguing with you here Kirk, just adding some information.  Iíve even heard of people making cylinder wall repairs in IC engines with JB weld.  I would never contemplate such a thing, but Iíve heard it has been done with success :facepalm:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on May 12, 2020, 03:53:33 PM
I think the issue would be that the repair block has a 3/8" hole through it to replicate the core, could not do that easily with JBW unless you poured it around a tube. Plus the CI will give a stronger thread than the JBW even tough it can be tapped.

I'd have stuck the repair piece with JBW myself rather than loctite.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 12, 2020, 10:00:28 PM
I considered JBW, but decided that if the loctite didn't work I could use it later.  As is, the patches seemed to be quite sturdy.  After a couple of night curing, I milled both sides leaving them proud a couple of thou, and then tapped the air supply hole 1/8-27 NPT.  I then fettled the valves removing a few thou from each side at a time until I couldn't see light between the valves and their plates.  If I can get the steam chest covers made a leak test could be done.

(https://pbase.com/kvom/image/170702494/large.jpg)

As an aside, I recently acquired this tool as a set from Travers, on sale.  It came with 3 bits of different sizes.  Couple of turns around a freshly drilled hole and I have no burrs and a nice tiny chamfer.

(https://pbase.com/kvom/image/170702495/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on May 12, 2020, 10:26:16 PM
I've seen those deburring tools in catalogs but never tried one. Sounds like you like it.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb on May 13, 2020, 07:21:11 AM
I use my one all the time though it is a smaller one with fixed size - upto 6mm holes, so much better than twisting your wrist on the straight shank type.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on May 13, 2020, 02:17:32 PM
Well done Kirk,  the Green cylinder block is a complicated casting with some challenging machining.  I'm looking forward to seeing the final assembly of the cylinder block.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 15, 2020, 01:20:04 AM
To start with some preliminary fitment tests, I installed the valve plates.  With the valve sitting on it at full travel, it appears that the orientation must be as shown here.  If reversed, the inlet is still open at full travel but one slit is only partially unblocked.  Notice that one slit is closed to the edge by .01".

(https://pbase.com/kvom/image/170708974/large.jpg)

Valve position when fully open.

(https://pbase.com/kvom/image/170708975/large.jpg)

Here we see the valves and valve rods assembled.  This is quite a tricky job.  I introduce the rod through the outside hole and then through the inside hole far enough to thread the inner nut onto the rod about half way.  Then pull the rod into the center space so that the valve can be place onto the plate; the valve is then slid onto the rod.  Turn the nut all the way to the inside so that the rod extends through the valve so that the outside nut can be threaded on.  This latter operation is tricky as there is little room for fingers.  I succeeded by pinning the nut against the outer wall and starting it by turning the rod to get it started.  Then tightened with a 3/16 wrench (5-40 threads).  The SW model shows two nuts on either side of the valve.  Both inner nuts can't be tightened too much as the hole the valve allows some vertical motion of the valve itself; thus two nuts to position the valve and two jam nuts.

(https://pbase.com/kvom/image/170708976/large.jpg)

The two nuts on the inside cavity are jam nuts for the "slide stem".  However, as made currently, there's only 2+ threads after the nut for this attachment.  So I plan to extend the threads once this is disassembled.  I do not believe that tuning the input requires adjusting the valve rod as its travel is controlled by angles of other adjustable parts.

I decided to make the initial valve covers from lucite so as to make the motion visible.  I had a full 12" square of 1/8" clear left over from previous projects, so I cut a 4.5x3.5" piece on the vertical bandsaw. This is a bit small and 1-off to warrant breaking out the vacuum table, so I decided to try a fixture method I saw on a youtube video from CNC NYC.  Basically I covered a fixture plate with painters tape as well as the bottom of the lucite, which is covered with a plastic skin.  The tape has Loctite 4581 applied, and the taped surfaces are clamped for several minutes.  Then off to the CNC mill (this would work for manual milling as well).

(https://pbase.com/kvom/image/170708977/large.jpg)

Afterwards I removed the skin from the top and separated the bottom with a Exacto knife edge.

(https://pbase.com/kvom/image/170708978/large.jpg)

I found that the left valve is a few thou proud of the block surface, I'll need to take that side apart and take a bit off the top.

(http://)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Johnmcc69 on May 15, 2020, 02:17:08 AM
 :ThumbsUp: very nice!
 I imagine you used an end mill for "drilling" the holes in the lucite?

 John
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on May 15, 2020, 02:21:21 AM
Quite a mechanism, love the plan for the clear covers to start, should make tuning a lot easier.    :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 15, 2020, 11:20:03 PM
Back in the shop for a short session.  After disassembly of the left valve rod, I extended the threading with a die for 3 extra threads and then reassembled.  Also reduced height of the valve by about .025".  Then  I found that the valve on the right side was rubbing against the lucite cover, so I did the same work there, including reducing the height by .010".

I then put on both covers, plugged the outside valve rod holes with 8-32 screws, set the valves closed, and applied 20 psi air.  No appreciable leakage could be heard or seen, so that was a relief.   :cartwheel:

Next up were the valve stem assemblies, show here:

(https://pbase.com/kvom/image/170712721/large.jpg)

The valve rod screws into the valve stem, while its die block and clevis are joined with a 5-40 screw and nut.  I made these parts a good while back, and now with assembly due ran into a few problems.  The first was that I drilled and tapped the set screws on the top and bottom of the clevis, rather than the sides.  Clearly the bottom would be inaccessible.   :hammerbash:  So I drilled and tapped one side so that top and side screws will secure the clevis to its rod.  The next problem is that there is not enough room for the model-size 5-40 screw head between the clevis and the back wall of the central pocket.  So my plan is to trim the heads of the screws to fit.  Once I'm able to attach the two assemblies, the rest of the inlet mechanism should be ready to attach,
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 15, 2020, 11:37:13 PM
Quite a mechanism, love the plan for the clear covers to start, should make tuning a lot easier.    :popcorn: :popcorn: :popcorn:

I deleted previous post after thinking session in the shower.   8)  Here's how I see things going.

First, adjust the eccentric rod so that the slide has equal motion on both sides.  Remembering that the dashpots should keep the valves closed, so that when the slide is in the center both are closed.  As the slide moves away from center and the trip on that side contacts the catch, the valve will move open as long as slide/trip are in contact.  Assuming no cutoff, I assume also that the furthest movement of the slide means full opening of the inlet.

Where should the piston be at full opening?  The elevation drawing from Dennis shows that in the center slide position both catches contact their trips;  but photo of the actual engine in RI shows the catches closer together than the trips.  The video of John's running engine shows them further apart.

If the piston and slide move in the same direction then full open can be at TDC.  Otherwise if in opposite directions then full open is at the center of travel as with D slide valves.

In any case, the tuning should be the same as with Corliss engines, so perhaps someone who has built a Corliss can chime in.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 16, 2020, 07:01:40 PM
I spent the best part of the morning assembling all the inlet valve-related parts, with a but of fettling thrown in.

(https://pbase.com/kvom/image/170714951/large.jpg)

The good news is that everything goes together more or less easily.  The bad news if that the motion is locked up.  Since the catch housings and dashpot clevises are just attached to the cross rods by grub screws, the problem is clearly with either the valve stems or bearing alignment, or both.  Next step will be to remove all but these parts and see how we can loosen up the action, perhaops with a little oil to help along.

I do need to add a second set screw to the dashpot clevises, and I see that I assembled the valve stem clevis with the horizontal screw on the inside where access is problematic, so I'll reverse those as well.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on May 16, 2020, 10:55:20 PM
Some more exploration revealed that the rear bearing carrier is too short so that when screwed down the cross shafts lock up.  If I loosen the nut and allow the bearing to float I can move the valve stem by turning the shaft.  I will use a feeler gauge next time in the shop to try to determine the gap, and then try to use shim stock to level it.

The two bearing carriers are fastened only by a nut on a threaded rod.  What keeps them parallel to each other are the two cross rods.

One observation today that was not obvious earlier is that the base of the valve stem is intended to slide on the bottom of the pocket, this preventing it from cocking and putting pressure on the valve rod.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on May 17, 2020, 12:37:20 AM
It looks GREAT Kirk, itís really coming together.  Lots of motion to see when you get it running.  You might even be tempted  to leave the clear valve chest tops in place so you can see the d-valves in motion.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on May 17, 2020, 02:38:59 AM
Kirk,
I know absolutely nothing about steam and less about the Green Automatic cutoff. So I can't offer you any help, and if I did it would be suspect but you are making good progress and I have been enjoying hollowing along.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis 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
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: zeeprogrammer 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?
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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:

ibefTGxBZNs
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.

(https://pbase.com/kvom/image/170732483/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: fumopuc on May 23, 2020, 02:16:28 PM
Hi Kirk, it is looking really great.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170743281/medium.jpg)

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.

(https://pbase.com/kvom/image/170743274/large.jpg)

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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170749297/medium.jpg)

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.

(https://pbase.com/kvom/image/170749294/large.jpg)

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

(https://pbase.com/kvom/image/170749295/large.jpg)

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

(https://pbase.com/kvom/image/170749296/large.jpg)

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

(https://pbase.com/kvom/image/170749298/large.jpg)

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

(https://pbase.com/kvom/image/170749299/large.jpg)

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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170751427/large.jpg)

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.

(https://pbase.com/kvom/image/170751428/large.jpg)

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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Kim on May 30, 2020, 05:27:10 AM
Neat little tool you made, Kvom.
It seemed to work quite well!
Kim
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Roger B on June 01, 2020, 08:13:12 AM
That's a complex little mechanism  :praise2:  :praise2: The form tool worked well  :ThumbsUp:  :ThumbsUp:  :wine1:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb 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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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. 

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jasonb 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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 01, 2020, 08:23:29 PM
I managed to make the opening large enough and deep enough to pass the gland by clamping it vertically in the vise as before.  I used a 1/4" endmill, and at first the part vibrated too much for comfort.  I then clamped a 2-4-6 block to it with a pipe clamp, and then worked the opening down by 15 thou at a time.  The opening isn't pretty. but it's covered by the cylinder head.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 05, 2020, 09:27:13 PM
Here's the point where I drilled the mounting holes, 3-48 body.  Work clamped by the "foot".  I had to shorten a .104" drill to get it to fit.

(https://pbase.com/kvom/image/170771326/large.jpg)

Then machined away the round boss to expose the opening.

(https://pbase.com/kvom/image/170771327/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 05, 2020, 09:38:44 PM
I attached the cylinder head with packing gland and piston to the frame;  this allowed trial fit of the crosshead.  After a bit of filling towards the cylinder end I obtained full travel.  The crosshead stays vertical without the slippers and v-grooves.

(https://pbase.com/kvom/image/170771328/large.jpg)

Then the moment of truth when the above assembly is added to the cylinder block using temporary studs made from 3-48 threaded rod.

(https://pbase.com/kvom/image/170771329/large.jpg)

While quite stiff, I can move the piston inside the cylinder with firm finger pressure, leading me to think the  alignment came out as well as I could expect.  Once the frame is mated to the bearing support and the crank disk to the conrod, I can attempt some running in to loosen it up a bit.  But there's still a lot to do to make that happen.

One thing is that I need to open up the hole in the crosshead for the piston rod.  It's currently a very tight fit with no way to adjust once I can't grasp the piston and push.  So using the .376 reamer should help with that.  There's still a bit of grinding to do on the frame casting, and I want to delay cutting off the "foot" of the frame until I'm sure nothing else remains to machine there.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on June 06, 2020, 10:17:29 PM
You are making a lot of good progress.  Getting the frame and V ways to line up with the cylinder head and bore is not an easy task.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 08, 2020, 12:03:04 AM
After reaming the piston rod hole to .376", the rod enters easily and now needs to be clamped by the two screws.  However, when mounted to the cylinder block, the nut on the inside of the frame is practically inaccessible.

(https://pbase.com/kvom/image/170777658/large.jpg)

Tightening the outside nut does secure the rod, but I think once the proper insertion distance is determined I'll need to detach the frame from the cylinder and free the crosshead so that the inner nut can be clamped down.

Spent most of the weekend engaged in the hunt for a new car as our trusty Kia Spectra5  has reached the end of its useful life.   :'(
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 15, 2020, 10:49:10 PM
After a week spent mainly with automotive issues, I am back on the Greene.  Specifically, I wanted to make the slippers that mate with the v-grooves in the frame to keep the crosshead on course.

My first try started with some 1/4" thick brass that I machined to dimension and set about milling the 18 degree angles by holding them in a vise and using angle bars. 

(https://pbase.com/kvom/image/170798176/large.jpg)

This was not a success for two reasons.  First, it's quite difficult to machine both angled faces so that they join in the center accurately.   Second, when placed in the frame it was clear that the actual angle is greater than 18 degrees.  I continued on increasing the angle and determined it is close to 21 degrees.  I'm pretty sure I set the crossfeed on the lathe properly when making the v-cutter tool, but have no other explanation for the difference.

So I changed course and cut the profile of 21 degrees into some 3/4" round brass rod.

(https://pbase.com/kvom/image/170798177/large.jpg)

This ensures that the profile is balanced.  Even though the slippers will be thin, I made it thick to avoid any movement during the machining.  Then with the rod still in the collet block, I could drill the two mounting holes (2-56 clearance).

(https://pbase.com/kvom/image/170798178/large.jpg)

After parting off on the lathe and cleaning up the end, I made successive cuts to bring the thickness down until it would fit under the crosshead in the frame.  Obviously this involved a lot of tries cutting 10 thou at a time.  Surface plate and 123 block were used to ensure the part was installed vertically each time.

(https://pbase.com/kvom/image/170798179/large.jpg)

(https://pbase.com/kvom/image/170798180/large.jpg)

Then back to the mill to counterbore the mounting screws.  Here I used a 3/16" endmill.  Then discovered that the driver for 2-56 hex heads had a diameter of .200".  Not having a 7/32" endmill handly but having some 2-56 socket screws, I needed to deepen the hole a bit and shorten the screws.

(https://pbase.com/kvom/image/170798181/large.jpg)

After attaching the slipper to the crosshead with just the cylinder head and piston on the frame, the motion was slightly stiff but not bad.  Then I put the entire assembly together with the cylinder block (no screws, just gravity), and found that the piston and crosshead moved very freely:

ErWIBYoTuTQ
At this point, I decided I could dispense with the big sprue at the crank end, and machined it away 30 thou at a time.

(https://pbase.com/kvom/image/170798182/large.jpg)

(https://pbase.com/kvom/image/170798183/large.jpg)

Checked the total length a couple of times to hit the target of 10.75".

(https://pbase.com/kvom/image/170798184/large.jpg)

Next time I'll endeavor to drill the 4 holes for mounting the frame to a bearing standard, then the corresponding holes in the standard so that the frame and conrod are parallel to the ground.

I've decided to omit the upper slipper for the time being, as it's clear it would end up being very thin.  Plus the top of the crosshead currently rides against surfaces created when milling the opening .
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 15, 2020, 11:01:15 PM
Some delicate shaping there, nicely done!
 :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dave Otto on June 16, 2020, 01:12:19 AM
Fussy little parts there Kirk, they turned out great!

Couldn't you have used your CNC mill  to put the counter bores in with a smaller cutter? That is probably what I would have done.

Dave
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 16, 2020, 01:31:51 AM
Dave, since these screws won't be visible I doubt it matters.  The depth needed depends on the height of the head, so I just eyeballed and pecked with the endmill trying the screw until it was below the peak.

Thinking about some future assembly, I realized that I couldn't install the conrod with the frame attached.  The pin that secures it to the crosshead is inserted from the inner side of the frame.  So I will need to secure the conrod first and then have both the conrod and crosshead pass through the frame opening before securing it to the cylinder.

If the frame is attached to the bearing standard, the crank end can't be attached to the crank pin without either detaching the standard or disassembling the crank end of the crosshead.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 16, 2020, 08:26:51 PM
The frame is mounted to the bearing journal by 4 5-40 screws.  To mate with the flat end of the frame, the matching area of the journal must be milled flat.  To determine the area to be milled, I measured the top surface of the frame end with a height gauge while the frame and attached cylinder block were on the surface plate.  This yielded the distance from the bottom  of the journal to the top of the area to be milled.  The vertical measurement of the frame's flat gave the  amount to be milled.

With these measurements I mounted the journal in the Bridgeport vise using a square to set the bottom of the journal vertical.  Then after the edge finder located the bottom surface in X, used a spotting drill to cut a line across the casting to mark the bottom of the flat to be milled.

(https://pbase.com/kvom/image/170801021/large.jpg)

Since the casting is curved, I started at the top with the first pass have a DOC of around 5 thou and locked the spindle.  Then as the tool moved to the right the DOC increased.  Once the milled line was erased the operation was done.

(https://pbase.com/kvom/image/170801022/large.jpg)

Drilling the clearance holes in the frame used all of the available Z on the Bridgeport. 

(https://pbase.com/kvom/image/170801023/large.jpg)

The drawings suggest using the frame holes to mark the journal, but I decided to trust the DRO in drilling the journal.  I did check them visually before drilling .3" deep and tapping while still in the vise.

Back on the surface plate the cylinder, frame, and journal are joined for the first time, although numerous disassemblies are in the future.

(https://pbase.com/kvom/image/170801024/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: gary.a.ayres on June 16, 2020, 10:47:48 PM
Great work - intricate and detailed.

An interesting engine taking shape...
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on June 18, 2020, 03:26:17 PM
That is a big step forward Kirk.  Thanks for posting your progress and the notes you have been sending to improve the drawings.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 19, 2020, 10:29:09 PM
Thanks for looking in, all who do.   ;D

The pieces I was missing to test full piston motion were the wedges that keep the crank end of the conrod together.  These are specified as .01" thick to match the the slots in the conrod.  I have a strip of 1" wide ground plate, so I sawed off a 2" long piece, milled it from .139" to .99", and used the technique I learned on youtube about fixing with painters tape and glue.

(https://pbase.com/kvom/image/170808952/large.jpg)

This worked well on the first wedge. but after removing so much of the tape that resist motion, the second wedge  moved under the force of the endmill.  So the second time I used the entire strip with only one end milled down.

(https://pbase.com/kvom/image/170808953/large.jpg)

Lots of holding force here, and it took considerable effort to price the rest of the piece off from the tape.

The wedges are still a little wide, but I installed them and connected the crank/conrod/piston/cylinder to test for motion.

o8eLj6IdCOE
I was holding the camera with one hand while turning the disk, so the video is a bit awkward.  I did find a few minor issues with the assembly.  One is that the disk is very close to the journal, so the bearing spacer needed to be removed.  I left the bearing protruding a slight amount, and that seems to work well enough.  Had I had the conrod complete I could have checked clearance and moved te mounting holes in the journal a bit to the left rather than centering.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 20, 2020, 10:55:06 PM
The remaining needed machining on the frame is to reduce the round boss on the side opposite the crosshead and then drill and tap the  two mounting holes for the governor.  The casting offers no good fixturing surfaces for these tasks, so  I concocted the following.  I cut 2 lengths of MIC6 aluminum  and machined them to identical rectangular dimensions, approximately 4.25" square.  On one of these I drilled and tapped 6 3-48 holes centered and in the same pattern as the cylinder head.  The other was to be drilled and tapped to match the crank end of the frame.

To hold the two ends, I moved the vise from the CNC mill to the Bridgeport and aligned it using a length of 1" diameter drill rod.  Luckily I'm still able to carry that vise.   :old:

(https://pbase.com/kvom/image/170811071/large.jpg)

Next I clamped the first piece of the fixture with the frame attached in one vise using a 236 block to set it vertical.

(https://pbase.com/kvom/image/170811072/large.jpg)

Now I could position the second fixture piece in the other vise against the frame end.  Once in position, I used a transfer punch to mark the mounting holes, after which I drilled it for 5-40 clearance.

(https://pbase.com/kvom/image/170811073/large.jpg)

With both fixture blocks screwed onto the frame, it could be rotated so that the the boss was horizontal.  This allowed removal with the side flutes of an end mill.  The amount to remove was determined by using the ends of the fixture block to determine Y0 via an edge finder, and then to mill the surface to Y=-1.8".

(https://pbase.com/kvom/image/170811074/large.jpg)

Before disassembling the frame from the cylinder, I used a height gauge and surface plate to measure the flat at the top of the flange at the cylinder end as well as the height of the mounting holes for the governor.  With the machined flat now turned vertical between the two vises, I used the edge finder to locate the holes, which were then drilled and tapped.  That completed the frame machining, so I could removed it from the fixture blocks and reassemble it to the cylinder block on the surface table.

With the governor gearbox attached along with its pedestal, I was happy to see my measurements work out.

(https://pbase.com/kvom/image/170811075/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 20, 2020, 11:04:31 PM
Fun to watch this one coming together, nice setup!
 :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 24, 2020, 01:15:44 AM
Tomorrow morning I have cataract surgery, so I don't know how soon I'll be able to work in the shop again.  Today's part is the lever that attaches to the eccentric ball joint and moves the long rod up and down to activate the exhaust valves.  Simple part starting with a small cutoff of 1" 1144 rod.  Like many parts, this was drilled and profiled on the CNC mill after I moved the vise back from the Bridgeport.

(https://pbase.com/kvom/image/170818311/large.jpg)

After tapping the smaller hole 3-48, I parted off on the lathe and cleaned up the part side on the Bridgeport.  Then I drilled the through hole to allow two 3-48 set screws on the 3/16" rod.

(https://pbase.com/kvom/image/170818312/large.jpg)

(https://pbase.com/kvom/image/170818313/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 24, 2020, 01:18:59 AM
Best of luck on the eye procedure. Follow all the instructions, eyedrops, all that! 
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: MJM460 on June 24, 2020, 04:11:40 AM
Best wishes for a successful procedure, Kirk.

May it all go well.

Engine build is going well.  Fascinating to watch it all come together.  I am sure that we will all be still here when you are up to getting back to it.  I donít expect it will be long.

MJM460
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jo on June 24, 2020, 06:51:29 AM
Best wishes Kirk, sooner it is done the sooner the recovery starts  :)

Jo
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on June 25, 2020, 12:40:40 AM
Kirk,
I hope everything goes well with the cataract surgery.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 25, 2020, 02:48:01 AM
Procedure done this morning; all well tonight.   :D
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jo on June 25, 2020, 05:47:42 AM
 8)

Jo
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: scc on June 25, 2020, 11:22:30 AM
Excellent.....Terry
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on June 29, 2020, 02:53:25 PM
Glad to hear your surgery went well and you are recovering.  Looking forward to seeing more progress on your Green engine.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on June 29, 2020, 09:35:43 PM
The other eye is scheduled for this Wednesday.  Vision in previous eye is pretty good.  Seems that after 60 years of being nearsighted I'll be farsighted now.  4 more weeks of eye drops, but one week of recovery gets pretty close to seeing well.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on June 29, 2020, 09:58:43 PM
Glad it's going well, its amazing how much easier than when they first started doing that kind of procedure. It will take a while for the eyes to settle in.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on June 29, 2020, 11:19:37 PM
Kirk,
Good to hear the first eye went well, I hope the other does so as well!
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on June 30, 2020, 01:22:38 PM
Good luck on the eye Kirk.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 02, 2020, 02:33:49 AM
Second eye went well and I can quite well at a distance even after half a day.  But close up is a problem ( I can just about tell the time on my watch).   I suspect that shop doings like using an edge finder or reading a micrometer will have to wait until I get some sort of glasses for reading.  But at least I got into the shop yesterday to sweep up a lot of swarf from the floor that had been there too long.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on July 02, 2020, 03:27:19 AM
Excellent!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Jo on July 02, 2020, 05:21:31 AM
Great news Kirk, give it time to sort itself out  ;)

Jo
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Admiral_dk 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
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170865294/large.jpg)

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

(https://pbase.com/kvom/image/170865295/large.jpg)

The ends of both halves need additional operations, and the ball needs to be annealed, drilled, and tapped.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170867757/medium.jpg)

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.

(https://pbase.com/kvom/image/170867758/medium.jpg)

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.

(https://pbase.com/kvom/image/170867759/medium.jpg)

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

(https://pbase.com/kvom/image/170867760/medium.jpg)

I need to do some more fettling on the hole in the swing arm to allow assembly.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170873987/large.jpg)

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:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170879257/large.jpg)

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.

p68Q044G9qU
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on July 16, 2020, 09:57:36 PM
Excellent, watching along...   :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Art K on July 17, 2020, 02:25:20 AM
Kirk,
Looks good, the rod clears and everything.
Art
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170882760/large.jpg)

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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170885508/large.jpg)

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.

(https://pbase.com/kvom/image/170885509/large.jpg)

Next session I need to make two rod ends and the rod to attach the swing arm to the slide.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis 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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170899080/large.jpg)

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.

(https://pbase.com/kvom/image/170899081/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: steam guy willy 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
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170906084/large.jpg)

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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom 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.

(https://pbase.com/kvom/image/170910928/large.jpg)

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.

(https://pbase.com/kvom/image/170910929/large.jpg)

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

OnJTIEkFAsw
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.

(https://pbase.com/kvom/image/170910930/large.jpg)

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.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on July 27, 2020, 11:17:20 PM
Fantastic looking parts - hard to tell they are a scale model not the full size!   :popcorn: :popcorn: :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on July 31, 2020, 11:41:58 PM
Bit more progress over the past few days.  I decided to try to save the exhaust bracket that I had messed up since I had no more of the 2" cast iron rod it was made from.  Remade the bearing cap, and was able to tap the mounting holes in the bracket well enough to old it.  I decided that in the worst case I could just loctite the two pieces and the bushing together.

It seems I hadn't finished the tiny "turnbuckle" used for fine adjustments of valve travel.  I had thread milled the left and right hand threads, but on a length of .099" drill rod that was too long.  Trimmed the right hand thread end to length and threaded with a die.  Then drilled a 3-48 nut and used loctite to secure it in the center.

(https://pbase.com/kvom/image/170920203/large.jpg)

Still needed to drill the clevis for set screws, but after that I could assemble the mechanism.  It's the same as the other but bracket is a mirror image.

(https://pbase.com/kvom/image/170920204/large.jpg)

Test fit to the cylinder block:

(https://pbase.com/kvom/image/170920205/large.jpg)

The ends of the two 3/16" rods that will be connected via a coupler are probably out of line by less than 20 thou before trying any shims.

Although I need disassembly/adjustment on the crankshaft end,   I'm not far from trying to get the first run.  I need to think about how to time the valves; since they are independent, it's not like a slide valve where you just have sync the valve and piston rods.  Does the MEM corliss plan have anything written about timing it?  Should be similar.  One issue is whether the weight of the dash pot pistons will be enough to close the input valves.  On the completed engine these are "assisted" by a spring below the base.

I ordered some Buna-N round and square o-ring material to see if I can build a workable belt to drive the governor. 

The good news is that the parts drawer seems only to have governor parts left.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 01, 2020, 07:54:50 PM
A few hours spent doing some last minute fettling on some parts, and then putting it all together:  first time all the major assemblies together.

(https://pbase.com/kvom/image/170922024/large.jpg)

Still a lot of adjusting to go before I can think of a test run. Issues evident from today:

- Slide needs centering.

- Crank side exhaust valve assembly motion is stiff.  Might need to shave the sliding grid a hair.

- Rod that links exhaust assemblies won't go into the coupler.  Thinking I'll open up the coupler a bit or move set screws closer to the end.

- Dash pot weight not enough to close inlet valves.  I may put temporary weight on each.

No rush to get it running as the pandemic has a ways to run.
-
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on August 01, 2020, 08:03:23 PM
Wonderful to see it assembled, quite a pretty engine.
 :ThumbsUp: :ThumbsUp: :ThumbsUp:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: fumopuc on August 02, 2020, 04:37:16 PM
Hi Kirk, impressive.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on August 03, 2020, 01:06:29 AM
Looks impressive Kirk, canít wait to see it run !
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on August 05, 2020, 03:48:23 PM
Hi Kirk.
Your model is looking very nice.  I am looking forward to the first running like all of the others following this build.  You have made a lot of progress on this build the last few months.

Getting all of the valves and valve gear adjusted will take some time and patience.  There are so many things moving at the same time, it is difficult to get it all coordinated.  At one time there was a step by step instruction sheet to guide you through the valve setting and adjustments but I could not find a copy it my computer files.  I will continue to look for it.  From my experience with this model, by the time you are finished making the adjustments you will have a new understanding of Nathanial Green's design. 

I believe Green was a very good engineer as was George Corliss.  Many people have read about the patent war between Corliss and Green's backers, however the court battle was not about steeling a CUT OFF VALVE DESIGN.  The court case was really about what could be patented or IF THE IDEA OF VARIABLE CUT OFF could be patented regardless of the mechanism used to accomplish the cut off. 

Maybe you should build a corliss valve gear engine now so you have the whole story.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 05, 2020, 09:37:48 PM
Rather than starting to fiddle with adjustments, I decided to do a bit more with the flywheel.  Since I am now able to run the 10EE in reverse for the first time ever (thanks to help from the Monarch section of PM), I now had the ability to turn across the full width of the wheel in one pass.  This was done by using a boring bar turned upside down.

I also removed the hole in the rim by facing off about .3" of the rim, which eliminated the connecting gaps in both the outer and side faces.  That said, I still need to do some finish lathe work using a sturdier way of holding it.  I used two difference mandrels, but still get wobble on the outer edges because of the weight of the wheel.  So I intend to make a new mandel that is supported by a tailstock center.

As for setting the input valves, these are a bit easier.  My normal approach for D valves is for the input to be full open when the piston is at midpoint in the cylinder.  This should mean that the opposite exhaust valve is fully open at that point as well. 

One peculiarity I discovered by mental review is that the oscillating activating rod means the exhaust valves act differently in an important way.  When the rod is rotating in one sense it is acting on both valves.  Thus both will either  be pushing into the cylinder or pulled outward.

After writing the above, I watched John's video again and can see that clevises are angled in opposite directions, and this in turn causes opposite motions.  That simplifies things a good bit. 

Since pushing one open means pushing the other closed, the two sliding grates need to be offset internally by the width of the grate opening or a bit more.  The openings are .08" wide and separated by .115".  So if I can determine when then valve should be open and can then position it, as long as it moves forward or back by > .08" I should be good.

By removing the valve cover on the opposite side, I can see the ends of both the fixed and sliding grates.  If the ends are even, then the openings are aligned and the valve is open.  I could also used a depth mike to measure the offset between the two.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 05, 2020, 09:39:37 PM
Quote
Maybe you should build a corliss valve gear engine now so you have the whole story.
Dennis

Trying to presell a set of Lane & Bodley castings?   ;D :headscratch:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on August 06, 2020, 04:24:05 PM
Hi Kirk,
Sorry if I offended anyone, as I re-read the posting, it does look like a sales pitch and I apologize for that.  It was not my intention.

The L&B engine is a fine model but as you know we sold our model business several years ago.  My interest in steam power has shifted to the history of these engines and the people who developed them. 

The history of steam power is a fascinating thing to study.  There are people, technology, manufacturing processes and new ideas that pave the way for more improvements in designs.  Sandy and I spent a lot of time (and money) collecting information and taking photos of stationary steam engines.  We have detailed photos of several hundred stationary engines and had planned to put them into a book that showed the progress of stationary engine design over the years.  The Henry Ford Museum and several small museums gave us permission to publish the photos we took of their engines without paying royalties on the published photos.  However, many of the photos were taken at museums which require a large royalty for permission to use photos of engines they own, even if you take the photos yourself.  That is understandable because the museums all have to support their exhibits and pay the people who care for them, however, the royalties would increase the estimated cost of our book to over $100 per copy which we felt was unreasonable and unsellable to recover the cost of publishing.  Presently, about 600 pages of the manuscript sit on a shelf in my den where I work on it occasionally just for the personal enjoyment, and it is well worth the effort and cost.

Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 06, 2020, 05:38:04 PM
My intent was jocular.   :cheers:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 06, 2020, 09:17:20 PM
After some fettling I was able to get the valves operating as I turned the flywheel.

cG82Cbpmq_s
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on August 07, 2020, 03:18:47 AM
Awesome!!  How long to a test run?   :popcorn:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 07, 2020, 01:56:00 PM
Nothing stopping me now but fear of failure.   :'(
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 07, 2020, 11:43:09 PM
I made the first attempt at setting the valves this afternoon.  Applied air and ....


Nada!!   :(

At 50 psi on the valve meter I could detect only a very light breeze coming from the exhaust opening in the bottom of the cylinder block.  Unfortunately the push connector I installed is 1/8" NPT and 1/8" OD tubing.  So air volume is likely way short of what's needed.  I ordered a connector for 1/5" tube from McMaster that will ship Monday.

I couldn't feel the slightest kick from either side, so there's a fair chance that the exhaust valves aren't sealing completely.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on August 08, 2020, 12:47:40 AM
Is it possible that the inlet valves aren't opening much? I like to back off yhe screws on an end cap to check that.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 08, 2020, 01:08:01 AM
With the transparent steam chest covers I can see the valves directly.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on August 08, 2020, 01:18:16 AM
With the transparent steam chest covers I can see the valves directly.
Thats handy!


Just had a flashback to an engine build where I thought I had all timed right but it wouldn't run. Finally traced it to a gasket where I forgot to punch the center steam hole.   :wallbang:
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 08, 2020, 09:35:04 PM
My push fitting for 1/4" tube showed up from McMaster (next day delivery!), so I hooked it up for some leak detection.  The major culprit thus far are the transparent covers.  Seems they don't provide a good seal to the block as they're thin (1/8") and flexible, plus there are only the 4 screws at the corners holding them down.  Given this, I don't see teflon gaskets working, and I don't want to try either of the two gasket liquids I have.

So I decided to machine a couple of brass covers and skip the see-through for now.  Once I can seal the steam chest I can check the exhaust valves.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 08, 2020, 11:27:02 PM
Covers milled from 3/16 brass.  I used the trick of securing using Scotch painters tape back to back with loctite adhesive between them.  Makes for a very secure hold on thin stock.

(https://pbase.com/kvom/image/170940067/large.jpg)

With the covers in place, the steam chest no longer leaks.  Now I'm seeing some oil being blown past the exhaust covers.  Still no resistance on the piston.  More investigation to come.

(https://pbase.com/kvom/image/170940068/large.jpg)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 09, 2020, 09:34:11 PM
Tested the exhaust valves today and they not valving whatsoever.   :'( 

I suspected I'd have issues but went ahead with full assembly given hope over experience.   :hammerbash:  I removed the outer covers to show part of the problem.

(https://pbase.com/kvom/image/170943174/large.jpg)

The valve passage has chipout on the bottom at the ends.  Sealing the passage relies on the covers.

(https://pbase.com/kvom/image/170943175/large.jpg)

If the semi-circular boss doesn't meet the fixed grate securely there will be leakage.  Too short and air escaped between, and too long the cover won't seal to the block.  Even with the valve closed there is air in the interior since there needs to be some space to allow the moving grid to slide.

The fix I contemplate at the moment is to make the fixed grid's length the same as the width of the block so that its ends are flush with the sides.  The bosses on the covers  and brackets would be removed.  That should remove any airpath around the end of the grid.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 10, 2020, 08:34:18 PM
Disassembled parts needed to separate the cylinder block preparatory to being able to assure air tightness in the exhaust valves.

(https://pbase.com/kvom/image/170945340/large.jpg)

(https://pbase.com/kvom/image/170945341/large.jpg)

Block has input valves and cylinder head still attached.  For the test I'll add the piston and frame-side head.  However, examination of my stock shows no remaining 5/8" brass rod to remake the stationary grids, so pending delivery of my order I'll start on other fixes.  Today I milled off the bosses on the exhaust covers.

I need to finish the flywheel and drill holes for direct lubrication and oil cups eventually, so now is a good time for that.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 14, 2020, 03:37:00 AM
I think I'm on a good path toward eliminating air leakage with the exhaust valve mechanism.  As a reminder, here is the assembly as designed:

(https://pbase.com/kvom/image/169419683/medium.jpg)

Like hobbits, all between the faces of the cover (blue) and brown bracket live in a hole. If the mate between the half circular bosses on these two isn't precise with the fixed grate (yellow), air can leak past even when the sliding grate supposedly closes the valve.

My solution is to do away with the semicircular bosses and make the fixed grate long enough to be machined flush to the sides of the cylinder block.  With the cover and bracket then screwed flush to the block, a good seal is  more assured.

So I remade both fixed grates somewhat long but did not cut through the grid openings, attached them in the hole, and carefully machined them flush taking about 1 thou off the block.  I added the piston and crank side head and screwed the covers tight on the side away from the crank.  When I applied air and moved the input valve open, I found that the exhaust opening was not emitting any air flow and the piston rod was driven outward.  So no leaks around the ends!
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 23, 2020, 12:56:19 AM
After doing all the exhaust valve rework I hooked the cyl block up to air.  Still seems leaky  but in manipulating the valves manually I got the piston to move.  So with enough pressure the engine "ought" to operate despite leaks.

So this afternoon I reassembled all the bits but one.  The coupler for the exhaust actuator rod seems to have gone walkabout.  I hunted around the shop for longer than it would take to make a new one, which I finally did.  Too late to to try to do all the myriad adjustments, so I called it a day and will see if I can get movement next time in the shop.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: crueby on August 23, 2020, 01:17:00 AM
First movement, great! 




As for the missing part, put out some cookies and shiny ball bearings as bribes for the shop gnomes, maybe they will return it...
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 24, 2020, 01:00:59 PM
No go Sunday.   >:(

After assembly and adjusting, two major problems.  First, too much resistance in the exhaust valves that I have now initially traced to the new bracket being 25 thou longer than the other, thus causing some binding in the rod connecting them.  This should be easy to fix.

The second problem is that the dashpot pistons are not heavy enough to close the inlet valves.  On the real engines there was vacuum created in the pots that applied force, and in the model a spring that's compressed when the valve opens helps to pull the piston down.  The spring is attached to a rod screwed into the piston that passes through the pot and through the base (which is elevated).  So I will make a temporary baseplate for the cylinder and raise it and the base of the bearing standards on 123 blocks to make room underneath for the springs.

I ordered a piece of 12x24" aluminum plate for the eventual baseplate on eBay, but I don't plan on using it until everything else is finished.  The design of the engine makes it almost impossible to remove the flywheel for transport.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 25, 2020, 05:05:57 PM
To provide a mounting surface for the cylinder block and dashpots, I cut out some 4.5x5" aluminum plate and drilled all the holes needed for a temporary baseplate.  But instead of the measure twice and cut once advice, I did the opposite.  So that plate got dumped and a second one made.  Wasted half the afternoon.  With the baseplates lifted 2", here's the result.

(https://pbase.com/kvom/image/170984193/large.jpg)

The dashpot assembly looks like this.

(https://pbase.com/kvom/image/170984194/medium.jpg)

As the piston is pulled upward by opening the valve, the spring is compressed.  The spring force pulls the piston back down once the valve is tripped or released.  The rod around which the spring is located is threaded, and the round disk at the bottom can be turned to compress the spring and add additional force if required.

I ordered the springs from McMaster for delivery tomorrow.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 28, 2020, 03:30:53 PM
My springs arrived but all the following day was occupied visiting apartments where my daughter is shopping for her first home.  Back at it yesterday.  Here's a dashpot piston and rod with the spring loading.

(https://pbase.com/kvom/image/170992090/large.jpg)

With both installed and the tension knob needing only a couple of turns, both dashpots are closing the input  valves as they are supposed to when the trips loose contact with the catch.

Unfortunately the exhaust valves refuse to operate smoothly or at all.  The fact that they are connected to two long rods passing through 4 bearings and fastened together only by pairs of 3-48 grub screws means that any resistance is likely fatal.  I unfastened the center bearing from the governor, which allows an easier meetup of the rods at their coupler.  That bearing looks like some fettling will get it closer to the needed line, but for the time being I'll ignore it.

Each valve assembly when bench-operated singly is smooth.  Similarly, each sliding valve when inserted by itself into the valve hole is very smooth.  So the next days will be locating where parts get out of alignment when screwed down.

Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on August 28, 2020, 10:00:03 PM
Hi Kirk,
The valves and assemblies look very good. 
I remember encountering some binding in the exhaust valve operation when building the prototype.  Your valves work free when standing alone like ours did.  For what it's worth, we found the length of the adjustable link between the rotating levers and the valve crosshead was too long and our assembly was trying to move the valve too far.  This is a very busy area and will need a lot of fiddling with the linkage and the working angle of the two oscillating levers to get the exhaust valves to move correctly.  If the long shaft from the eccentric is rotating through too large of an angle, reducing the amount of rotation would require a longer lever arm where the shaft connects to the eccentric and vice versa.

I really like the progress you have made and am looking forward to seeing the engine run.
Dennis
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 28, 2020, 11:45:05 PM
Dennis, I figured that the adjustable link at the crosshead adjusted the valve travel.  At my last test though it doesn't look like the shaft is rotating over the same angle as the arm, and the valves barely move at all.  I drilled the mounting holes large (.104 to .116) to give some adjustment wiggle when attaching so as to line up the valve stem.  That helped some.

I believe the main issue now is not transmitting enough torque along the shafts and having slippage around the grub screws.  I think I'll pin the shaft to the eccentric lever arm next and the screws for holding it are difficult to access.  Some larger screws for the coupler might be an improvement as well.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Dennis on August 30, 2020, 09:50:17 PM
Those are good ideas Kirk, personally, I do not like set screws and much prefer the tapered pins for those connections.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on August 31, 2020, 02:03:28 AM
I removed the swing link assembly and decided to fix the actuator rod with Loctite 638 with the two grub screws in addition.  I also shortened the threaded rod that connects the lever to the ball joint.

(https://pbase.com/kvom/image/170998395/large.jpg)

Assembling these parts is a bit tricky.  First, one needs to disassemble the ball joint to thread the rod into the ball.  Trying to do so with the joint intact just causes the ball to rotate freely rather than screwing in.  Then the lever must be screwed on.  Doing it after the ball joint is reassembled wont work because the swing link gets in the way.  Only now can the joint be reassembled inside the link.

While these parts were out I managed to do so some cleaning up of some bearings so as to provide lubrication paths.

(https://pbase.com/kvom/image/170998394/large.jpg)

The two small bearing blocks had 1/16" holes drilled when made, but now I needed to loctite the bearings and then extend the holes into the bores.

For the main standard, I drilled a 1/8" hole in the bottom center and installed a small length of 1/8" drill rod.  A matching 1/8" shallow how was drilled in the bottom of the bearing, so that when assembled the bearing won't shift.  I then drilled a .104" hole through the bearing cap, and then a 1/16" matching hole through the top of the bearing.  At some point an oiler will be placed atop the cap, but for now a small amount of oil can make its way down to the shaft.

The other standard and bearing will get the same treatment at a later date.

Note for future builders.  The small bearing block that mounts on the other standard is nearly impossible to remove with the outer standard in place.  I suggest using a socket screw for the bottom hole, as that can be accessed.  A hex head screw would need a 90 degree nut driver and much patience.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: gary.a.ayres on September 02, 2020, 08:27:37 AM
Disassembled parts needed to separate the cylinder block preparatory to being able to assure air tightness in the exhaust valves.

(https://pbase.com/kvom/image/170945340/large.jpg)


It's looking beautiful...
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on September 02, 2020, 02:30:45 PM
I noticed some "lost motion" in the exhaust valves, and some of it appears to be in the eccentric being too loose in its strap. It's possible that movement inside the strap is like backlash that can be ignored as long as the rotation is not reversed.   I finally got the valves to actually move in sync with the flywheel and applies air.  Nothing moving, but at least the sound is something other than the steady hiss of leaking air.  I'm going to remove the eccentrics and try to tighten up a bit.  While they're out, I'll drill for the oilers.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on September 08, 2020, 07:32:39 PM
I took everything apart to address some issues that I put off.  The first was to make the fit of the exhaust eccentric to its strap a bit better.  One issue is that the two halves of the strap need to clamp the pivots of the swing arm, so there's a balance between the fit of the two halves and the diameter of the pivots.  I ended taking 25 thou off of the straps and 9 thou off the pivot diameter.  Obviously I needed to be careful as taking too much off the strap would cause the eccentric to jam; it's a bit of a balance.  There's still some play between the strap and eccentric, but it's much smaller than before.  The upper half of the strap was also drilled for an oil passage.

While apart, I also did the same ops on the inboard standard and bearing as I did before on the outboard, so both now have paths for lubrication.

In order to be able to visually see that open/shut status of the exhaust valves, I came up with this idea.  Both the fixed and stationary halves were marked with dimples on the back ends to ensure they stay paired.  Then they were clamped together in the open position and a line scribed in the fixed valve marking the end of the moving one.  Then the moving valve was moved  slightly to a closed position and another line scribed.

(https://pbase.com/kvom/image/171023163/large.jpg)

The idea is that when timing the exhausts, I'll have the rear covers removed and can see when the moving valve is at the open and closed positions.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on September 14, 2020, 09:25:58 PM
My wife suggested that the 20+year old toilet set in our bathroom had outlived its time (who knew you could wear out a toilet seat?).  But being the agreeable sort I went to Lowes and got a new one.  While installing it I pulled a muscle in my back, so no shop time again today.  What does that have to do with the Greene engine you ask?

Since the exhaust valve motion is still being contrary, with the angle of the clevis being close to 90 degrees to the connecting rod, I decided to model the assembly in SW.  Here the angle is more forgiving.  After some measurements I found that I had used the wrong drawing/SW part for the rod ends on the connecting rod.   :hammerbash: :killcomputer:

So the intra-hole distance as built is .72" rather than .63".

Easy parts to make correctly, so I'm hoping tomorrow the back isn't as sore and I can make progress again.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on September 24, 2020, 04:26:05 PM
My scheme for marking the open and closed positions on the fixed grid ran into an issue, as I had forgot that the sliding grids move in opposite directions from open to closed, so I needed a different closed mark on one grid.

In testing with the valve links at .625", I saw the the sliding grid moved much further than the distance between marks.  So I needed to investigate how to adjust the grid travel.  To do so, I made a Solidworks sketch:

(https://pbase.com/kvom/image/171064375/medium.jpg)

I determined that the actuating rod moves through the 13+ degree angle based on the eccentric's .14" travel and the lever's .59" length.  The clevis is represented by the .59" line and the link by the .7" line.  The ends of both lines are constrained to remain on the dotted line.

The angle of the clevis has an effect as well, but I chose 30 degrees below horizontal as a reasonable value.  By varying the lever's length and measuring the distance between the two points on the dotted line, I can determine the grid travel.  With a link at .625, which is what the engine had, the travel would be .155", which verifies what I saw.  I had to increase the link length to .7" to get the travel to .1".

Based on the as-drawn dimensions of the grid, the required travel needs to be in the range of .08-.1".

When I first machined the grids early in the project, I reasoned that spacing the openings further apart would make timing easier, and did so.  But when I remade the fixed grids to be full length in the block, I reverted to the original spacing.

So now I need to decide whether to continue with the current grids and try to adjust the travel to what's needed, or to remake the fixed grid and have more wiggle room in timing.  I'm leaning towards the latter even though that means another major disassembly of the engine.

I'll also mention that I remade the valve crossheads in steel replacing the brass ones.  They seem to slide much more easily as the brass caused a lot of friction for some reason.
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Craig DeShong on September 28, 2020, 09:57:41 PM
Following along Kirk;  :popcorn: :popcorn:

Lots of parts to get all working together. 
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: Roger B on September 30, 2020, 11:51:00 AM
I'm still following in the background  :ThumbsUp:  :ThumbsUp:  :wine1: That's a tricky linkage to set up so all runs well  ::)
Title: Re: Greene Automatic Cutoff Steam Engine
Post by: kvom on September 30, 2020, 01:55:38 PM
Thanks for looking in people.  I've had a lot of distractions lately, but I hope to be able to try again with a corrected link soon.

** edit **

I made a link that was .7" long, but still had grid movement over .2".  The problem is that I can't get the start angle of the clevis small enough before the crosshead hits the end of the bracket.  I considered shortening the crossheads, but I think making shorter links until I get the necessary movement will be more prudent.

It's pretty clear that the clevis angle has the greatest effect, something that appears obvious after some thought.

My plan now is to continue with the grids as they are to get it to run, but to remake with wider slot spacing later on.