.
Last edited:
36x60x54 Twin Tandem Mill Engine
- Thread starter Kawka777
- Start date
Help Support Home Model Engine Machinist Forum:
Check out the row of Mesta Corliss engines on the assembly floor.
10th photo down.
What a massive place that was.
https://historicpittsburgh.org/collection/mesta-machine-company-photographs
Look closely and you can see the flywheel in the foreground.
Not my photo. (posted under the fair use doctrine for copyrighted material, for educational purposes).
You can see the reversing links in this photo.
The website said these mill engines were quickly reversible.
10th photo down.
What a massive place that was.
https://historicpittsburgh.org/collection/mesta-machine-company-photographs
Look closely and you can see the flywheel in the foreground.
Not my photo. (posted under the fair use doctrine for copyrighted material, for educational purposes).
You can see the reversing links in this photo.
The website said these mill engines were quickly reversible.
Last edited:
Twin tandems being assembled.
Not my photo.
If you zoom in, you can see a worker standing to the left side of the walkpad, near the crankshaft (to get a feel for scale).
Not my photo.
If you zoom in, you can see a worker standing to the left side of the walkpad, near the crankshaft (to get a feel for scale).
Last edited:
From the Historic Pitsburg website.
Not my photo.
Dual piston valves on low pressure cylinders, with valves located on side of cylinder, not on top, and thus directly inline (or close to that) with the eccentrics.
You can see the reversing links towards the crankshaft.
.
Not my photo.
Dual piston valves on low pressure cylinders, with valves located on side of cylinder, not on top, and thus directly inline (or close to that) with the eccentrics.
You can see the reversing links towards the crankshaft.
.
Last edited:
From the Historic Pitsburg website.
Not my photo.
Same engine, different view.
Shows the HP and LP valves on the same rod.
Since the HP line enters the center of the HP steam chest, then I would guess inside admission.
That would explain the single flange on the end of the HP steam chest (exhaust to the LP steam chest).
I have never seen rods between cylinders on a horizontal steam engine, but there they are.
.
Not my photo.
Same engine, different view.
Shows the HP and LP valves on the same rod.
Since the HP line enters the center of the HP steam chest, then I would guess inside admission.
That would explain the single flange on the end of the HP steam chest (exhaust to the LP steam chest).
I have never seen rods between cylinders on a horizontal steam engine, but there they are.
.
Last edited:
Richard Hed
Well-Known Member
- Joined
- Nov 23, 2018
- Messages
- 2,518
- Reaction score
- 656
Very nice photos. I'm amazed that you could find all this stuff. I'm particularly interested in these Corliss'.
Richard Hed
Well-Known Member
- Joined
- Nov 23, 2018
- Messages
- 2,518
- Reaction score
- 656
When you say you started on this, do yhou mean drawings?There are several Stuart designs, some like the Sirius are currently available. The Sun and Star were also popular and then there is the less well known MTB range of about six engines.
I did start work on a Stuart S-Type which was an actual high speed engine (not model) used on gen sets but interst wained so it has not got far beyond the drawing stage.
I think most of us liek to see what is going on rather than have it hidden away
Richard Hed
Well-Known Member
- Joined
- Nov 23, 2018
- Messages
- 2,518
- Reaction score
- 656
This looks do-able. I found that Graham has a book (or two) but not available in this country. At least not easy to find. Do you know if there are any plans available?
.
Last edited:
May be better to have a new thread for further discussion of enclosed engines rather than derail this one any more.
Last edited:
Yes, lets try to stay on the original topic, because the natives are getting restless.
I have removed some of my off-topic material, but I will start another thread.
.
I have removed some of my off-topic material, but I will start another thread.
.
Greentwin,
Thank you for those pictures. I have not seen these ones before, especially the one with the twin LP valves. I do have a copy of the Mesta Machine sales magazine that shows a few engines from 1919, which I think are the same ones you found.
Link below from the Smithsonian.
https://library.si.edu/digital-library/book/plantproductofme00mest
JacobB, I would bet you are right about the valves being driven in some manner as you drew. I am searching for something around the area that may have been a shaft pedestal. I have not found much yet.
I finished roughing out the LP valve chest, so I will continue my way back to the rear bed plates. The porting on the LP valve body is as we described before. The large square flanges in the side are exhaust, top is starting valve, side circular flange is from HP piston.
I was thinking about this engine in its entirety and realized there is likely some really complicated reversing mechanism on this engine… A scary thought this early in the project.
Modeling the rear bed plate will make this engine whole on one side minus a bed plate under the LP and HP cylinders, which is nothing special and the same for both sides. Luckily for me, the stuff I have drawn right now is an exact mirror image to the other side. Only the rear bed plates are different. I should be able to get a view of the engine in its entirety soonish.
These bed plate drawings are going to be rough to model. It is amazing that guys back then could have actually cast this thing... just like the other models, I will simplify it a decent bit.
By the way, thanks again for the suggestion for Alibre. I did end up buying it. Well worth it!
Mike
Thank you for those pictures. I have not seen these ones before, especially the one with the twin LP valves. I do have a copy of the Mesta Machine sales magazine that shows a few engines from 1919, which I think are the same ones you found.
Link below from the Smithsonian.
https://library.si.edu/digital-library/book/plantproductofme00mest
JacobB, I would bet you are right about the valves being driven in some manner as you drew. I am searching for something around the area that may have been a shaft pedestal. I have not found much yet.
I finished roughing out the LP valve chest, so I will continue my way back to the rear bed plates. The porting on the LP valve body is as we described before. The large square flanges in the side are exhaust, top is starting valve, side circular flange is from HP piston.
I was thinking about this engine in its entirety and realized there is likely some really complicated reversing mechanism on this engine… A scary thought this early in the project.
Modeling the rear bed plate will make this engine whole on one side minus a bed plate under the LP and HP cylinders, which is nothing special and the same for both sides. Luckily for me, the stuff I have drawn right now is an exact mirror image to the other side. Only the rear bed plates are different. I should be able to get a view of the engine in its entirety soonish.
These bed plate drawings are going to be rough to model. It is amazing that guys back then could have actually cast this thing... just like the other models, I will simplify it a decent bit.
By the way, thanks again for the suggestion for Alibre. I did end up buying it. Well worth it!
Mike
The engine in post #84/85 uses Stephenson's links, which is a well understood and well documented arrangement that use to be popular on locomotives and many other engines. Uses two eccentrics, and the engine is reversed by shifting the links up or down.
Below is a Stephenson's link valve gear arrangement; the horizontal bar protruding to the left is a temporary thing I added for the motion study.
Below is a Stephenson's link valve gear arrangement; the horizontal bar protruding to the left is a temporary thing I added for the motion study.
Not a tandem but may be of interest
https://modelengineeringwebsite.com/Reversing_rolling_mill_engine.html
https://modelengineeringwebsite.com/Reversing_rolling_mill_engine.html
That cylinder in the center looks like it works like a simplex boiler feed pump.
I guess it controls the links.
.
I guess it controls the links.
.
Hi All, It has been a busy few weeks with a kitchen remodel and some crazy work hours. I did manage to get the rear bed plate started but its a slow process due to the complexity of the drawing. I am having alot of trouble figuring out how to simplify.
I did learn a few things about this engine in the mean time.
As JasonB suggested, I did finally find the shaft that connected the two LP valve spools so they work as one. It was not easy to find as it was labeled in a strange way. I found references and control diagrams of the cylinder used to reverse the engine. It was a steam operated cylinder with a seperate spool valve that was controlled by hand.
Interestly, the control pulpit for this engine was in the current location, roughly 50ft away and in line with the blooming mill. There was a system of linkages and cables that connected the hand levers in the pulpit to all the controls on the engine. It was insane. I only found bits and pieces of references, but enough to give me a pretty good idea on how it looked. Unfortunately, there is no clear GA to show.
Some historical bits about this particular engine. This engine was used from 1914 until about 1922. During the short time it was in service, one of the HP and LP cylinders had to be rebored. There was also some foundation issues that caused some movement on the crank alignment. The engine was scrapped and replaced with a DC motor.
I did learn a few things about this engine in the mean time.
As JasonB suggested, I did finally find the shaft that connected the two LP valve spools so they work as one. It was not easy to find as it was labeled in a strange way. I found references and control diagrams of the cylinder used to reverse the engine. It was a steam operated cylinder with a seperate spool valve that was controlled by hand.
Interestly, the control pulpit for this engine was in the current location, roughly 50ft away and in line with the blooming mill. There was a system of linkages and cables that connected the hand levers in the pulpit to all the controls on the engine. It was insane. I only found bits and pieces of references, but enough to give me a pretty good idea on how it looked. Unfortunately, there is no clear GA to show.
Some historical bits about this particular engine. This engine was used from 1914 until about 1922. During the short time it was in service, one of the HP and LP cylinders had to be rebored. There was also some foundation issues that caused some movement on the crank alignment. The engine was scrapped and replaced with a DC motor.
"The engine was scrapped and replaced with a DC motor."
That will please Pat
The controls sound similar to that engine I linked to a few posts earlier with the small valve and cylinder to operate the reversing gear from a remote position.
That will please Pat
The controls sound similar to that engine I linked to a few posts earlier with the small valve and cylinder to operate the reversing gear from a remote position.
One of the great crimes of the Century was the scrapping of most of the old steam engines in the US.
We just don't value our technological heritage like we should, in my opinion.
We don't value technical knowledge like we should either............just rambling......
Makes you wonder what powered the DC motor ?
Was it a giant rectifier, or on-site DC generation ?
Electrification started in ernest in the US in about 1896, when Westinghouse/Tesla came out with their 3-phase power distribution system., After the electrification of Niagra Falls with a Westinghouse system, there was never any question about the way things would go after that, as far as AC or DC systems.
Someone once stated (forget who) that AC is just varying DC, and I think this is true.
I know of one nearby wastewater plant that until recently was using pots of liquid dielectric to vary the speed of their 5KV large (perhaps 2,500 hp) incoming pumps, by raising or lowering electrodes in the dielectric. Very crude system, but very effective and reliable, and has worked well for 50 years.
.
We just don't value our technological heritage like we should, in my opinion.
We don't value technical knowledge like we should either............just rambling......
Makes you wonder what powered the DC motor ?
Was it a giant rectifier, or on-site DC generation ?
Electrification started in ernest in the US in about 1896, when Westinghouse/Tesla came out with their 3-phase power distribution system., After the electrification of Niagra Falls with a Westinghouse system, there was never any question about the way things would go after that, as far as AC or DC systems.
Someone once stated (forget who) that AC is just varying DC, and I think this is true.
I know of one nearby wastewater plant that until recently was using pots of liquid dielectric to vary the speed of their 5KV large (perhaps 2,500 hp) incoming pumps, by raising or lowering electrodes in the dielectric. Very crude system, but very effective and reliable, and has worked well for 50 years.
.
Last edited:
Hello All,
It has been a crazy few weeks and had very little spare time. Luckily for me, I am back at it. I mentioned this before, but this drawing for the right rear bed plate is throwing me for loops. There just was not a standard dimensioning practice. Through all that, I think I have the rear bed plate roughed out so the major dimensions should be correct. I will work another night on it and get to a point where I can make the left rear bed plate. I fully expect to have to redraw these bed plates once we get the engine mocked up in the assembly and figure out how it works. The main cylinders and valve chests are symmetric between the sides, so once I get the left rear bed plate modeled, we can actually see the engine in its entirety.
I did have discussions in passing with a local foundry, and they are fully on board to make some small casting runs. I guess they have done stuff like this for others and said the easily way for them to cast is with 3d printed models (printed exactly as the desired part but a bit larger of course) and simply add draft angles using automotive body puddy. Something to think about I guess.
GreenTwin,
The DC motor is powered via a MG (motor -generator) set. So they use a huge 3 phase AC motor and couple it directly to a few DC generators. Then those generators produce the main power for the mill motor. Each main mill motor would have its own big (MG set and a bunch of smaller MG sets to control the stator fields (of both the dc generators and mill motor) for direction and speed. Look up Ward-Leanord speed control if you are interested. This was the way to control big motors before the introduction of drives.
I felt so sad seeing the roster of the steam engines that were all striken in the 1920's. This is all lost to time.
It has been a crazy few weeks and had very little spare time. Luckily for me, I am back at it. I mentioned this before, but this drawing for the right rear bed plate is throwing me for loops. There just was not a standard dimensioning practice. Through all that, I think I have the rear bed plate roughed out so the major dimensions should be correct. I will work another night on it and get to a point where I can make the left rear bed plate. I fully expect to have to redraw these bed plates once we get the engine mocked up in the assembly and figure out how it works. The main cylinders and valve chests are symmetric between the sides, so once I get the left rear bed plate modeled, we can actually see the engine in its entirety.
I did have discussions in passing with a local foundry, and they are fully on board to make some small casting runs. I guess they have done stuff like this for others and said the easily way for them to cast is with 3d printed models (printed exactly as the desired part but a bit larger of course) and simply add draft angles using automotive body puddy. Something to think about I guess.
GreenTwin,
The DC motor is powered via a MG (motor -generator) set. So they use a huge 3 phase AC motor and couple it directly to a few DC generators. Then those generators produce the main power for the mill motor. Each main mill motor would have its own big (MG set and a bunch of smaller MG sets to control the stator fields (of both the dc generators and mill motor) for direction and speed. Look up Ward-Leanord speed control if you are interested. This was the way to control big motors before the introduction of drives.
I felt so sad seeing the roster of the steam engines that were all striken in the 1920's. This is all lost to time.
It is possible to add draft at the design stage. You will also have to add machining allowances to all surfaces that need it, again do it at the design stage. Then your 3D prints will have teh draft and just need the surface ssmoothing before they are ready to use as patterns.
My usual way is to include the draft as I go and then make a copy of that part which can then have machining and shrinkage allowances added to become the pattern.
You will also need to use cores for that bed pattern unless those cross head guides are separate., the core boxes that they are formed in can be derived from your 3D model
My usual way is to include the draft as I go and then make a copy of that part which can then have machining and shrinkage allowances added to become the pattern.
You will also need to use cores for that bed pattern unless those cross head guides are separate., the core boxes that they are formed in can be derived from your 3D model
