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Bending 4130

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rawlin27

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Jun 26, 2016
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Hi guys,
I've just started bending the first longeron for my S1s fuselage. I made a plywood radius block to screw to the jig and tweak the tube around. As far as alignment is concerned, it has worked perfectly. There is however a slight flattening at the inside and a tiny bulge (about 1mm in a 2 meter spirit level).
Is this typical/normal when working with 4130 cold?? I know that some people use a gas canister or tyre rim to bend the longerons so I assume that this is unavoidable using this method. It's the first time that I've worked with 4130 so a bit of confidence is required at this early stage!!
Thanks in advance for any advice!

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