Online Community of Zenith Builders and Flyers
See also http://www.ch601.org/tools/brake_plans.htm
The bolts you see all along the upper angle keep it firmly to the base. There must be enough distance between the bolts and the edge to allow room for the flanges of the spar.
When I wanted to bend 0,032 sheets I had to replace the piano hinge with an array of stronger hinges.
The bending of the 0.040 angles for the fuselage was done by a friend of mine at a metal workshop.