DIYbanter - View Single Post - question on bending .040 aluminum on a brake

Grant Erwin

wrote:

I need to bend some 6061T6 .040 aluminum that is a U shape, 8" wide
with 2" legs. I wanted to know if I mark exactly the 8" and make the
bend will the radius cause the overall width to be less or more than
the 8". I dont want to waste material by trying to bend 8" width and
then the overall width is either 7 7/8" or 8 1/8", any suggestions?
Thanks,
Mike

You need to search on bending allowance. I archived this from this NG a
long time ago:

For 90 deg bends in cold rolled steel the following works well for me:- L=
(0.71xT)+(1.57xR) Where L=length of stock for each bend. T=material thickness
R= inside radius of bend. For hot rolled substitute (0.64xT) for (0.71xT) The
eight times rule is that a vee width of eight times material thickness will
give you an inside bend radius equal to the material thickness.

I would be somewhat concerned about cracking on T6 heat treated 6061. Maybe
you should anneal the material in the bend areas?

Grant