When I assembled the aft back-to-back bulkhead, I noticed that the aft most bulkhead was riding up on the weldment and therefore not able to sit down flush against the adjacent bulkhead. As a result, I trimmed the clearance around the weld so the bulkhead would sit down. Unfortunately, when I went to re-fit the now assembled aft bulkheads into the aft fuselage, I noted that the holes for the aft bulkhead no longer lined up perfectly...duh... Rather than redrilling the holes and creating figure 8 holes, I decided to add a doubler to the lower flange. I will still have figure 8 holes in the base flange when drilled, but I will now also have the reinforcement flange to provide a more pristine assembly. Yes, I know it is not perfect, but...make a mistake...find a solution and build on.....
Doubler after forming drilling and trimming
Installed location. Note relief for aft spar
Riveted in place. Flanges squeeze together when in place.
