Author Topic: Greene Automatic Cutoff Steam Engine  (Read 3147 times)

Online Tennessee Whiskey

  • Full Member
  • *****
  • Posts: 3760
  • Springfield, Tennessee. USA
Re: Greene Automatic Cutoff Steam Engine
« Reply #45 on: May 31, 2019, 09:42:07 PM »
Iím silently following along  8)

Cletus

Offline kvom

  • Full Member
  • ****
  • Posts: 1927
Re: Greene Automatic Cutoff Steam Engine
« Reply #46 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.



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



Drill .5x3.5".



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



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



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.


Offline crueby

  • Full Member
  • *****
  • Posts: 8540
  • Rochester NY
Re: Greene Automatic Cutoff Steam Engine
« Reply #47 on: June 02, 2019, 01:32:59 AM »
Excellent - watching along from the peanut gallery (and popcorn gallery, ... )

Offline kvom

  • Full Member
  • ****
  • Posts: 1927
Re: Greene Automatic Cutoff Steam Engine
« Reply #48 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.). 



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.



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.

Offline crueby

  • Full Member
  • *****
  • Posts: 8540
  • Rochester NY
Re: Greene Automatic Cutoff Steam Engine
« Reply #49 on: June 02, 2019, 06:47:39 PM »
 :popcorn: :popcorn: :popcorn:

Offline bouch

  • Full Member
  • ****
  • Posts: 54
Re: Greene Automatic Cutoff Steam Engine
« Reply #50 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.

t=657s

The Greene starts at about the 5:20 mark...

Offline crueby

  • Full Member
  • *****
  • Posts: 8540
  • Rochester NY
Re: Greene Automatic Cutoff Steam Engine
« Reply #51 on: June 03, 2019, 03:01:39 AM »
Great video! Thanks for sharing!

Offline kvom

  • Full Member
  • ****
  • Posts: 1927
Re: Greene Automatic Cutoff Steam Engine
« Reply #52 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.

Offline Dennis

  • Full Member
  • ****
  • Posts: 38
Re: Greene Automatic Cutoff Steam Engine
« Reply #53 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

Offline kvom

  • Full Member
  • ****
  • Posts: 1927
Re: Greene Automatic Cutoff Steam Engine
« Reply #54 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.



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.



It's ready to drill the center hole, but I decided to leave the setup as is until I get back from the trip.

Offline Jasonb

  • Full Member
  • *****
  • Posts: 6417
  • Surrey, UK
Re: Greene Automatic Cutoff Steam Engine
« Reply #55 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.

Offline kvom

  • Full Member
  • ****
  • Posts: 1927
Re: Greene Automatic Cutoff Steam Engine
« Reply #56 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.

Offline Art K

  • Full Member
  • ****
  • Posts: 1096
  • Madison, Wisconsin USA
Re: Greene Automatic Cutoff Steam Engine
« Reply #57 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
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline kvom

  • Full Member
  • ****
  • Posts: 1927
Re: Greene Automatic Cutoff Steam Engine
« Reply #58 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.



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.



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



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.


Offline crueby

  • Full Member
  • *****
  • Posts: 8540
  • Rochester NY
Re: Greene Automatic Cutoff Steam Engine
« Reply #59 on: June 11, 2019, 03:20:00 AM »
 :popcorn: :popcorn: :popcorn: