The 4x12 aluminum sheets were laid flat on a work bench and a cardboard pattern used to mark out the blanks. I made the pattern from cardboard 1/2 inch bigger than the router jig. I used a cheep electric sheer for cutting and they worked fine. I did have to apply some protective tape on the foot where it contacted the sheet because it had a tendency to scratch the aluminum.
I clamped 5 nose rib blanks between the master form and the backer form and drilled the 3 jig pin holes on the drill press. These holes would also match the hole in the router form blocks for finally edge cut.
