David R Brooks wrote:
My project involves folding 1.5mm and 2mm aluminium sheet (think tube
amplifieers


Cool, Iv'e built a few of these myself.

snip

I am bending using a brake (the machine with a hinged "wing" that
swings up to make the bend.) The only adjustments I have a
1. Set the scribed bend-line forward of the edge of the clamping bar.
2. Set the "wing" to swing a little in front of that bend line.

Is there a convenient rule for converting thickness & bend-radius into
those settings? The design has 2 U-folded pieces fitting within each
other (simplifying somewhat): I want them to fit with minimal
clearance (obviously, not negative clearance!), so my bending needs to
be accurate.


Look he

http://www.engineersedge.com/dist_bend_line.htm
http://www.engineersedge.com/bend_allow_calc.htm

I haven't done this in 40 years, but these look correct.

--
Gary A. Gorgen | "From ideas to PRODUCTS"
| Tunxis Design Inc.
| Cupertino, Ca. 95014