Tip: Drilling / making a small hole bigger.
 

Before I started working on my 7A QB, I never knew how hard it could be to drill a good hole. :( There are a number of places where pilot holes have to be enlarged to #12 for AN3 bolts. Here's a tip from Walt (707RV), my tech advisor and brother that really helped me. Instead of just using larger drill bits, use a Unibit to enlarge the hole! There are a number of places where multiple layers have to be drilled together. When I did it with regular bits, half the time the bits would jam and I'd get fragments between the layers. Even though the Unibit might not get all the layers to full size, it helps enough that the final hit with the #12 is very easy. :)