Torsion bar material.

[Andy Walker]

I was wondering If anybody knows what type of steel the torsion bars are made from? I'm assuming they are all the same, but specifically the 2 used for the Sdkfz 7 kit.

[Adrian Harris]

Probably what's commonly sold as "Piano Wire".

Adrian.

[Jerry Carducci]

Probably what's commonly sold as "Piano Wire".

Adrian.

That would be my guess. That's what I've used in the past for scratch builds. Can't say I knew the hardness of the material I used, no longer have access to a hardness tester. But I did test a length of whatever I wanted to use, the exact length I wanted to use as a torsion bar. I'd test the deflection
using a spring balance, similarly to the way armorers tested the fusee spring in a Vickers MG; I would attach the spring balance to a proper swing arm and with a protractor see how much deflection I got at various weights of 'pull'. I knew that the weight of the model was more or less divided by the number of axles so when I found a rod or bar of steel that gave me the per axle deflection in degrees I wanted for a particular weight value I wanted, Bob's your uncle. The torsion bars I've made were generally thinner than those in the 1/6 scale as I was making them for 1/10 scale but the process should scale.

Easy Peasy....

Jerry

[Andy Walker]

Probably what's commonly sold as "Piano Wire".

Adrian.

Thanks Adrian. I did wonder if Piano wire could be used. I've found various companies selling 'spring steel', but it appears to be that it has to be heat treated before use. 'Piano Wire' doesn't....its ready to use.