S/N 10 Shay

[Dan Rowe]

The real start of this design is the Graham Shay engine.



I had spent a bit of time thinking and discussing Shay shop number 10 when Regner made a model of it several years back. The photo is the only engineering information available except the Lima Numerical Record lists the engine as 8" x 8" and the drivers are 24". All the rest of the engineering information on Shaylocomotives.com is educated speculation based on catalog data.

The photo is nearly straight on so using the driver diameter I scaled it in cad and started the drawing process.





Now I have to think of how I will use each bolt I can see in the photo for a prototypical use. The Lima Shay frame drawings start with steel I beam frames none of the wood frame drawings exist. There are a few key photographs of early Shays that I will show as this built progresses.

Cheers Dan

[PJPickard]

Always liked this one...looking forward to watching this progress!

[crueby]

Always fascinating to see how mechanisms developed. Will be watching along!


Chris

[RReid]

I also am looking forward to this build, and will be following along.

[cnr6400]

  Look forward to this build.

[Admiral_dk]

Oh man - this should be interesting 

Where is the  and 

[crueby]

Is the model in your picture the Regner version or one you built?

[Dan Rowe]

Thanks, everyone for the interest in this build I will try and catch the thread up to date with the build.

Chris the model engine is a very rare Grahan Shay made by Gail Graham over 20 years ago as best as I can remember. It belongs to a friend of mine for who I am doing the metalwork. Bob is doing the woodwork to my design in his shop. I will be making a crude frame as a platform for the machinery to get the fit all right then we will combine the two parts of the build. Bob has been sending me detail photos to include in this thread.

I scaled the drawing knowing the drivers are 24". I took the right truck box used on S/N 181 the oldest Shay I have drawn and some of the critical dimensions and added them to the photo. That is a close match to my eye. I measured the boiler diameter as the rivet seam just shows on the forward edge of the front cab post. I get 42" not the 48" listed on Shaylocomotives.com.

I also added the scaled-up Graham to see how it would look again that is good to my eye for the engine.



I started the drawing with a 2" boiler that would be close scale 42" and I remembered that the Graham engine needs a bit of steam as it has a 1/2" bore and a 5/8" stroke. I did not have enough steam with a 2" boiler with the Sykes and the Hackworth Graham engine so I decided to stretch the frame for a 2.5" boiler to make sure that there was enough steam capacity For the steam engine.

Cheers Dan

[wagnmkr]

This is going to be so interesting to follow.

[Dan Rowe]

I want to point out a few unusual features on this early Shay the fourth one built and the first believed to have a builders photo. The engine has the valve chest extend beyond the cylinder cover. This is typical of very early Shays S/N 181 with a 2-7x7 engine that has the same feature. I wondered about this for some time and I just kept ordering old cylinder cards until I found the old 10 x 10 cylinder with this feature. Well, it is a double D slide valve. The steam passage is straight perpendicular to the valve face top and bottom. There are two exhaust ports that connect to a common exhaust passage. The top valve covers the top exhaust port and controls the top steam passage. The lower valve works the bottom end. Why did they use a very old design? I do not really know but they were building sawmill steam engines with the same double D slide valve so they simply went with what they knew how to build. The 8 x 8 double valve cylinder card does not exist and neither does the 7 x 7. I had to add the feature to my drawing of S/N 181.

The wood frame is not straight it is bent up in the middle. Why who knows. The sawmill certainly did not cut the heavy timbers that way. They must have used greenwood and used the bridge timbers which have 4 vertical rods to bend the frame to the position in the photo. I thought about the curve of the camera lens but I added straight lines to the building in the background and they do not have any curve. This detail will not be in the model.

Now to the trucks. The right bearing box known as the truck box in Lima forms is a very simple casting the base has the usual bolt tabs on each side but they are missing on the top. The face of the box is plain without any stiffing ribs. The oil holes are simply drilled in the face and just above the lineshaft bearing cover.  The left bearing box known as the pedestal on Lima forms can not be seen, but there is a photo of S/N 21 that shows this detail which I will show when we get to the truck build.

Finally, look at the pinions. They are rear of the bull gear not in the usual position forward of the bull gear. This means we will have to reverse the engine to make the reverse lever work correctly. Not really a problem with a two cylinder Shay.

Cheers Dan

[crueby]

Looking forward to seeing a diagram of that double-valve setup, hard to visualize it. Were the two sliders independantly adjustable? If so, was that part of the reason maybe, to tune the sliders to the ports? We have had many cases where a slider for a model had to be re-made to get the gaps/solid parts the right dimensions.
That center span on the frame looks like the way a modern long flatbed trailer does, with the arch in the middle. Helps take the load of the boiler/engine in the middle maybe?

Great stuff!
 

[cnr6400]

Hi Dan, Maybe the frame constructors used a crowned beam assuming the great weight of engine and boiler mid-span would eventually cause it to sag to a straight condition. Better that way than to build it straight initially and have it sag below straight in use. Just food for thought. It's an interesting Shay! 

[Dan Rowe]

Chris. here is Card 1649 the 10' x 10' double D cylinder to show the old style. I did not track down the valves or the valve rod so all we know is what is shown. I think they would have been able to adjust the valves independently but that is something that would take further research.



CNR yes that must have been what they were thinking. Only S/N 9 and S/N 10 had the bridge timbers to warp the frame so I guess they decided it was overkill.

Cheers Dan

[crueby]

Interesting setup. By that time d valves were well understood, wonder what they were thinking?

[Dan Rowe]

Chris, the only reason I have ever come up with is Lima OH was really back in the sticks in the 1880s it might have been a simpler pattern and core for a small machine works to produce so they turned the sawmill engine upright and sent it into the woods for more trees.

Cheers Dan