Smokebox Fabrication

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318J
Posts: 34
Joined: Mon Apr 04, 2016 3:27 pm
Location: Meramec Valley, MO

Smokebox Fabrication

Post by 318J » Thu Oct 05, 2017 5:39 pm

Today in the weld shop I pulled out the roller and tested rolling some steel for the smokebox. My plan is to roll a sheet of steel to the proper radius and TIG weld the joint to form the smokebox.

One problem- The thickest steel I can reasonably roll is 1/8''. The blueprint calls for 1/4'' to be used in the smokebox. My biggest concern is that the thinner smokebox could warp when being welded. I plan to machine a spacer to take up the extra 1/4'' distance the 1/8'' thick smokebox would leave between it and the boiler, as I have seen others do.

Has anybody done something similar? Most models I've seen have used a pipe or tube, but I have had difficulty locating the correct diameter. (Not to mention pipe and tube is cost prohibitive for me)

Any thoughts on using the 1/8'' thick steel over the 1/4'' called for?
20171005_141435.jpg
A piece of 1/8'' mild carbon steel I test rolled to proper radius.
-Sam
Meramec Locomotive Company, SLFF Railroad
"Preserving the Past and Ensuring Our Future"
https://www.facebook.com/meramecloco

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Marty_Knox
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Location: Michigan, USA

Re: Smokebox Fabrication

Post by Marty_Knox » Thu Oct 05, 2017 6:38 pm

On the first Allen 0-4-0 I used the Allen cast two piece smokebox. On the second one I'm building I made the smokebox from the same pipe as the boiler shell. The 1/8" material won't last as long as thicker material. Even full size smokeboxes corrode at a rapid rate. Think about it - you have SO2 gas in the smoke from fire if you're burning coal or oil, you mix with the steam and water in the exhaust, and you end up with sulphuric acid. A good reason to keep your smokebox clean.

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johnpenn74
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Re: Smokebox Fabrication

Post by johnpenn74 » Sat Oct 07, 2017 8:13 pm

If you are trying to meet an odd size (like 7 or 9 inches) I believe tube is available in that size. On my 440 I am thinking I will sleeve over a piece of 9 over the 8.375 boiler shell.

JP
John Pennington

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Allen 4-4-0 Narrow Gauge Conversion
Reading A5a Camelback 0-4-0
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318J
Posts: 34
Joined: Mon Apr 04, 2016 3:27 pm
Location: Meramec Valley, MO

Re: Smokebox Fabrication

Post by 318J » Sat Oct 07, 2017 10:40 pm

I'm trying to meet 8.5'' or 8.75'' OD (Print calls for 8.75''). Rolling my own steel tube in that size would cost less than $20, compared to the $80-90 quote I got for the less ideal 8.5'' tubing.
-Sam
Meramec Locomotive Company, SLFF Railroad
"Preserving the Past and Ensuring Our Future"
https://www.facebook.com/meramecloco

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Marty_Knox
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Re: Smokebox Fabrication

Post by Marty_Knox » Sun Oct 08, 2017 7:25 am

8" pipe is 8 5/8" (8.625). I am sure your saddle can be machined to 4.3125" radius rather than 8.375". 8" pipe should be easy to find, and inexpensive.

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Marty_Knox
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Joined: Thu Jan 09, 2003 6:50 pm
Location: Michigan, USA

Re: Smokebox Fabrication

Post by Marty_Knox » Sun Oct 08, 2017 8:11 am

You're going to need to find the pipe for your boiler shell anyway.

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