First step was to make a hole pattern template.
The plate is cut from 3/8” ply at 4-3/4” square. This matches the width of the fuselage.
Mark the plate with the thrust lines to match the firewall.
Attach the template to the plate (I used 3M 77 for this).
Centerpunch all the holes on the template.Using a drill press drill pilot holes through at all locations (I used 3/32” bit).
Drill the 1” hole at the bottom only with a 1” Forstner bit.
