Small steel I beam

[Wrist Pin]

Hi Guys
I am working on a small bronze cannon for a friend.
He wants it mounted on a steel "cradle" in the style of Civil War era shore batteries.
We want to mount this cradle on steel I beams similar to photos we see on line. We figure the I beams should be 1/2" to 3/4" high and around 8-10" long to look scale.

I have looked everywhere to find a supply of this tiny I beam with no luck. Short of milling I beam out of a solid steel bar, does anyone know where I can get some of this??

 

[mklotz]

Here's a source of plastic structural shapes...

http://www.plastruct.com/picat/STRCTURAL_SHAPES_FTGS_9.pdf

If plastic is too weak to support the cannon, perhaps you can conceal some metal supports within the structure to handle the load.

This subject has been discussed here before...

http://www.homemodelenginemachinist.com/index.php?topic=3616.0

Perhaps you'll find something useful there.

 

[Chazz]

I've seen small (extruded?) Aluminum I beam?

Cheers,
Chazz

 

[Wrist Pin]

Hi Chazz
Trying to avoid aluminum as my friend has steel in mind.

Hi mklotz
Thank you for the link. I see BrianS has come up to the same problem. They are simply not available. How much trouble do you think I would have milling 1/2" square CRS across 8-10"? If I take a 3/8" end mill and go down 3/8" deep down both sides, will the remaining shape stay true? I don't haver the facilities to stress relieve.

 

[Dan Rowe]

ASAP Source
Has A-36 channel as small as 3/4" that can be reduced in thickness and silver soldered back to back. That is a lot simpler and cheeper than doing it with an angle milling cutter with a ball end.

If you plan to mill a section I would use A-36 hot rolled not cold rolled to prevent warping. I have made 1/2" I beam from 12L14 but I had to keep flipping the stock and make the same cut on both sides to control the warp

Dan

 

[Wrist Pin]

Hi Dan
Thanks for the link! That is an option. I will discuss this with my compatriot.
Anyone else?
Jim

 

[MachineTom]

If you have a machine that has backgear, A 3/8 wide mill cutter 3-4"D would do that in a fraction of the time of an EM. The cutter needs to be a greater diameter than the Quill. Setup using a right angle plate. Or find someone with a horizontial mill.

 

[Chazz]

A company called Namasco has a 3" Deep x 2.33" Flange I Beam @ 5.7Lbs/Ft.

Regards,
Chazz

 

[Wrist Pin]

Thanks Guys
Dan's back to back channel sounds like the best option so far.

Thanks MachineTom
That would be the fastest if I had the machinery.
Jim

 

[Dan Rowe]

This is the setup I used to make 1/2" I beams from 12l14.

This was the first attempt before I started fliping the stock.

Here are the finished beams they are 20" long.

Dan

 

[Wrist Pin]

Wow Dan!
They look great! How much did you take off on each pass before flipping the piece??

 

[Dan Rowe]

I do not remember the depth of cut but I made 3 or 4 passes before flipping the stock. I used 2 end mills the rough one was 3/8" OD with radius corners. The other cutter is in the photo and it is a 100 angle cutter with a 1/8" ball end.

I had to use another set of hold downs to force the stock back into the fixture plate after cleaning and deburing.

Dan

 

[Dan Rowe]

Here is a test piece I made today starting with 1" channel. I cut down the legs to make a 3/16" flange first then I thinned the back to to about .03 thick and silver soldered the two sections back to back. Then I cut down the top and bottom flange.

I was shooting for 7/8" but it is more like 13/16" tall. (1/4" grid)

Dan

 

[Wrist Pin]

Very nicely done, Dan.
Since I don't silver solder, (if my Dad was still alive he could show me), I was thinking of drilling a series of small holes in one channel. Then I could have the guys in the shop weld the two together, after, as you say, machining the C channels down to look "right". These are mostly for authentic looks, they are not for structural integrity.

 

[Swede]

Wow, Dan, those look great! Very nice job! :bow: