Main frame

This forum has been created for discussions and questions related to the construction of and machining of components for scale replicas of the Greenbriar, Cheat & Elk #12

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Main frame

Postby shayloco » Sun Dec 12, 2010 2:06 pm

The main frame member on the GC&E is a 20 inch I beam with truss rod supports. That is a 2.5" high beam in 1.5" scale. Since no such beam or channel is available in that size I am looking for options on how to make that beam.

One suggestion was to mill out a 3/4" thick piece of steel to simulate the I beam on one side. Leave the inside flat. This would result in a nice hefty beam, but milling the angle to simulate an I beam could be problematic on a piece that is about five feet long.

I thought about making an I beam by welding three pieces together. I'm afraid it would be shaped like a banana when the welding was done. One could alternate welds from one side to another to try to minimize the warpage.

Anyone else have any thoughts?

-Larry
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Re: Main frame

Postby Kevin Jenks » Sun Dec 12, 2010 3:03 pm

There are standard I-beam sizes (american standard beam) that might fit the sizes you need, check out this table: http://www.structural-drafting-net-expert.com/steel-sections-i-beam-s-shape.html I found it on this website http://www.structural-drafting-net-expert.com/steel-beam.html The size you indicated is at the bottom of the embedded scroll page. The only thing I don't know is where you can find a supplier for the general public. When I need structural steel like that I have contacted local welding job shops that deal largely with structural steel elements. The ones that are willing to deal with you sometimes have good connections.
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Re: Main frame

Postby shayloco » Mon Jan 31, 2011 4:58 pm

I just stumbled across an article in Modeltec, May 1992, page 24, where T. Parkinson describes cutting bar stock to simulate the I-beam frame of 3156. He used 1018 cold rolled steel. A fly cutter with a carbide insert was used to take heavy cuts and hollow out the material, then the edges of the beam were made by angling the milling head 12 degrees. He describes the finished product as "terrific". One bar on which they took all the cuts from one side before turning it over had to be straightened.

-Larry
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Re: Main frame

Postby shayloco » Tue Apr 05, 2011 7:04 am

Here's my version of a 20" I-beam in 1.5" scale. It is 2.5" tall, 5 feet long, made from 1/8" steel pieces silver soldered together. The silver soldering went well using an oxy-acetylene torch. No distortion from the silver soldering. It's very strong, I placed it on two cement blocks and put my 220 lbs on the middle of the beam and didn't notice any significant deflection. There are many holes to be drilled through this beam but the final product will have two massive furnace bearers and some heavy truss rods to help support it.

I know it is more an H beam than an I beam but once everything gets assembled on the loco no one will notice.

One more to go.

-Larry
Attachments
IbeamFrame4.jpg
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