Brief Description: Marking fin skin hole locations
There are probably many ways to do this, but here is the technique I used to mark the location of the holes in the fin skin. First I marked all the desired hole locations on the substructure. You have to be careful on the aft spar to leave enough room in the flange to not interfer with the doubler. Then I attached tracing paper to the trailing edge of the rudder and folded it forward over the substructure. I tried to be careful to keep the paper tight to make its location repeatable. Then I marked on the tracing paper the location of the desired hole locations I drew on the substructure. Next I pulled the tracing paper back, installed the skin. Taped it in place using non-flexible aluminum tape. I then folded the tracing paper back and used the center punch to mark the location of the holes onto the skin. Once this was done, I removed the skin, marked all the hole locations and made minor adjustments to ensure the rivet lines were straight. Next I drilled all the holes in the skin to a #40 size.
