Armstrong RML Cannon Model. Making angle iron pieces.
by John
There are quite a few pieces of angle iron in the Armstrong cannon. In the original they measure 95x95mm, and are about 15-16mm thick. Also, there is a definite radius between the 90º faces. At my 1:10 scale, the material becomes 9.5mm x 9.5mm, and about 1.5mm thick.
After considering various options, which included using extruded aluminium, and bending some sheet mild steel, I decided on the following solution….
I bought some offcuts of RHS (rectangular section) with 1.5mm steel thickness, and used a bandsaw and milling machine to produce the required dimensions in steel.
This is a piece of 50 x 25mm rectangular section steel which has been bandsawn in half, then the corners cut off to produce 10x10mm angle of the correct thickness. Sawn pieces on the right, ready to be tidied up on the mill. The bandsaw really takes only a 5/8″ wide blade, but that is a 1″ wide blade which I made up with a silver soldered join, and it works fine! Note the improvised wooden fence.
johnsmachines 
Hi John, All looks pretty impressive. As for the holes around the muzzle face, I am completely baffled as why they there, never seen them in any cannon before!! Please enlighten me. Silver soldering the bandsaw blade is something I have never tried, always have butt fusion welded them, did you need to anneal the joint after soldering?
Keep up the good work.
Chris
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Hi Chris, I was told that when loading the cannon, a protective plate was held by 2 pins on the muzzle, so it was not damaged by the loading process. Dents around the muzzle apparently can affect accuracy.
As for silver soldering, I do not anneal afterwards. Rarely get any breaks.
Cheers. John
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Thanks for that, the girders look really good.
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