Building the 2.5" Scale Shay

Where users can chronicle their builds. Start one thread and continue to add on to it.

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Soot n' Cinders
Posts: 819
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Building the 2.5" Scale Shay

Post by Soot n' Cinders » Sun Nov 17, 2019 11:34 pm

With the stack bolted back in place, it was time to drag it out to the railroad for a test. The solder originally used to hold the bolt rings on, failed while shuffling cars around the yard. So the oxy-acetylene torch was wheeled over and the soft solder replaced with silver braze while A friend used some pliers to hold things in place for me. The hard solder gave no issue, but I suspect I may have fuse the two bolt rings. Oh well...
IMG_0171(1).jpg
This is the stack shortly after brazing, the flux residue having been cleaned off with a wire wheel in a cordless drill.
IMG_0173.jpg
Here is the stack after having completed two round trips over the railroad. This clearly shows why the soft solder was no good. The steel has taken a blue temper from the heat, so 500 degree solder didnt stand a chance.
IMG_0174.jpg
After realizing the paint I was planning on wouldnt hold up to the heat either, I went back to an old time treatment of steam oil and powdered graphite. It definitely looks nice! But will take more running to fully cure it. Ive heard boiled linseed oil is a good oil to use in place of steam oil. It will react to heat similarly but will also air dry at room temperature. Something to investigate I think.

Finally, here is the video of the stack in action! This is climbing the ruling grade of 1.75%, and I purposefully over fired just before filming to get it to smoke. Unfortunately, it is still difficult to see the swirling action because of the mottled sunlight.
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

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makinsmoke
Posts: 1875
Joined: Thu Jul 10, 2003 12:56 pm
Location: Texas Hill Country

Re: Building the 2.5" Scale Shay

Post by makinsmoke » Mon Nov 18, 2019 8:43 am

That is an amazing amount of work.

Beautiful job!

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NP317
Posts: 2187
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon

Re: Building the 2.5" Scale Shay

Post by NP317 » Mon Nov 18, 2019 11:01 am

Very nicely done!
RussN

Soot n' Cinders
Posts: 819
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Building the 2.5" Scale Shay

Post by Soot n' Cinders » Mon Nov 18, 2019 2:45 pm

Thanks gents!
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

Glenn Brooks
Posts: 1913
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: Building the 2.5" Scale Shay

Post by Glenn Brooks » Mon Nov 18, 2019 11:53 pm

Soot n' Cinders wrote:
Mon Sep 24, 2018 5:32 pm


The second, and biggest improvement was changing the blast nozzle. I started with 9/32, which was found to be too small. The exhaust went from beats to a roar going up grades and back pressure was robbing the engine of power. So I bought a brass pipe plug to play with while the stainless steel one was set aside. I started with 5/16" and stepped up by 1/32" till I went too big. 13/32" was the step too far with the steaming ability reduced to the point the engine exhaust wasnt able to get the boiler over 100 psi without overfiring the boiler. So the stainless nozzle was drilled out to 3/8" and that seems to be the magic size.
Tristan,

I am doing some winter maintenance on my Ottaway, and looking at changing out my blast nozzle. Can you advise what is your cylinder diameter measurement? I am curious about what your loco’s nozzle to cylinder diameter turned out to be...

Thanks,
Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

Soot n' Cinders
Posts: 819
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Building the 2.5" Scale Shay

Post by Soot n' Cinders » Tue Nov 19, 2019 12:24 am

Glenn Brooks wrote:
Mon Nov 18, 2019 11:53 pm
Soot n' Cinders wrote:
Mon Sep 24, 2018 5:32 pm


The second, and biggest improvement was changing the blast nozzle. I started with 9/32, which was found to be too small. The exhaust went from beats to a roar going up grades and back pressure was robbing the engine of power. So I bought a brass pipe plug to play with while the stainless steel one was set aside. I started with 5/16" and stepped up by 1/32" till I went too big. 13/32" was the step too far with the steaming ability reduced to the point the engine exhaust wasnt able to get the boiler over 100 psi without overfiring the boiler. So the stainless nozzle was drilled out to 3/8" and that seems to be the magic size.
Tristan,

I am doing some winter maintenance on my Ottaway, and looking at changing out my blast nozzle. Can you advise what is your cylinder diameter measurement? I am curious about what your loco’s nozzle to cylinder diameter turned out to be...

Thanks,
Glenn

Glenn, the cylinders on the shay are 2in bore and 2.25in stroke. I’m still using the 3/8in blast nozzle orifice with much success. The original 9/32in orifice used was sized using the 1/7th of the bore diameter rule that has been mentioned on here several times, but I have a lot more exhaust to deal with than something like a Pacific. My crankshaft has to turn about 110rpm to reach 1mph. This puts my engine running around 300rpm for normal track speed. The top speed is around 450rpm, at which point the imperfections in the balance show up and begin to vibrate the whole locomotive. But I digress. Higher speeds means more exhaust and a larger nozzle was needed to accommodate that without choking the engine.
I’d recommend threading the pipe for the blast nozzle so caps or plugs with various size holes could be tested. I spent a two days playing around with various sizes and designs before settling on a plain 3/8in hole. Your mileage may vary with your Ottoway.
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

Glenn Brooks
Posts: 1913
Joined: Mon Nov 10, 2014 1:39 pm
Location: Woodinville, Washington

Re: Building the 2.5" Scale Shay

Post by Glenn Brooks » Tue Nov 19, 2019 1:38 am

Tristan, thanks much! I should have asked also what is your boiler diameter?

Looks like your bore diameter ratio is slightly over 1/5 th cylinder diameter. (1:5.32)

I’ve read elsewhere - somewhere- that geared locos require generally greater nozzle diameter and steam jet flow than conventional engines... so what you selected through experimentation makes sense.

My Measurements for oriface diameter, stack height, minimum stack diameter, etc for the Ottaway don’t readily match up with the accepted formulas, so mainly looking to compare values with a couple of proven builds, to estimate which direction I should go to possibly adjust nozzle size and nozzle height- given the fixed size castings on the Ottaway.

Thanks much.
Glenn

2
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

Soot n' Cinders
Posts: 819
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Building the 2.5" Scale Shay

Post by Soot n' Cinders » Fri Dec 13, 2019 10:28 am

More work on the shay now that school is out for the holidays. Got the cab all mocked up in foam board. Had to enlarge it a little bit from the prints because the decking on my shay is wider than the prints call for. I’ve already tested it out some by climbing up on the stand but I’ll take the whole thing up to the railroad next week for testing.
While I’m up there, I also have a knock to find. I believe it’s the front universal joint but I’m not certain yet.
Attachments
CF9E2634-EBFD-4251-97B1-1345777FD146.jpeg
E6659E3D-2A1F-4FC4-9FE9-C40CB7C16A51.jpeg
64B55B4B-0788-443E-8DA6-71D6C45915D0.jpeg
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

Claralinja
Posts: 3
Joined: Mon May 02, 2016 7:57 pm
Location: South Australia

Re: Building the 2.5" Scale Shay

Post by Claralinja » Sat Dec 14, 2019 4:14 am

Hi Tristan,
Have you yet considered how you are going to do the sliding side windows.
I have just completed our. I used 3mm acrylic sheet ("Perspex") running in 10x10x1.5 aluminium channel. This channel was rebated 5mm into the top and bottom of the window frames.
I then glued 3mm thick timber to the outer surface of the perspex.This was positioned so it slid along the top of the channel.
I painted the timber both sides before gluing. This meant that the fame could be seen through the perspex. It works and looks quite well.
IMG_0300.JPG

Soot n' Cinders
Posts: 819
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Building the 2.5" Scale Shay

Post by Soot n' Cinders » Mon Feb 03, 2020 12:02 am

Been a while since the last update, been learning about woodworking and making some test shavings. But have the framing for the engineers side roughed in. Still needs a little fine tuning and then holes for the dowel joints drilled. But can’t assemble it anyway till I have the wood for the inset panel ready.
C59FC0E6-576F-49E4-BFEF-68727FA346A7.jpeg
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

Soot n' Cinders
Posts: 819
Joined: Wed Jun 27, 2012 5:24 pm
Location: Marietta, Georgia

Re: Building the 2.5" Scale Shay

Post by Soot n' Cinders » Thu Mar 05, 2020 8:13 pm

More work on the cab! Actually quite a bit since the last post. Both side walls are basically complete, just awaiting glue. The engineers side needs a notch cut in it as well. But work is progressing on the roof rafters and front wall. Trying to decide how to handle the center panel on the front wall. I was going to just do several pieces of oak, but some of my reference pictures show it inset like the side wall panels. If I do the inset, it’ll be walnut like the sides. Decisions, decisions...
5DBFE7AE-AA91-42C4-AF4B-77BB078124D8.jpeg
-Tristan

Projects
-2.5" scale Class A 20 Ton Shay

Berkman
Posts: 144
Joined: Wed Aug 16, 2017 7:55 pm

Re: Building the 2.5" Scale Shay

Post by Berkman » Thu Mar 05, 2020 8:32 pm

Looks awesome! What's next to do after the cab?

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