Today I back drilled the inboard forward floor stiffeners through the floor skin. I then spent a good hour figuring out how to hold the outboard stiffeners in place for drilling. What I came up with was to mark a centerline on each end, then drill the forward hole on the bench. After clecoing the forward end in place on the fuselage, I used a couple of angles and four clamps to jig the aft end in place (photo 1). It worked quite well; hopefully the other side won't take near as long...
Jig for holding outboard floor stiffener in position for drilling.
Aft end of left outboard floor stiffener is drilled.
