Center Bulkhead, F-705 Bulkhead

I had never fully installed the control sticks and control column to see if my bushing sizes were correct, so I decided to take a step backwards and do that to test fit everything (it'll get tight once the seat ribs are in). It all fit really well.  I disassembled it all, bagged the hardware and taped it to the control columns, and stored it for later.

Back to the F-705 bulkhead:

The center section bar and bar doubler get match drilled to the rear spar attach bulkhead.  I drew a line down the middle of the long bar to line up with the pre-punched holes.  There are no measurements in the drawings or instructions to say where any of the holes actually go, but logically it should all be centered (the bar and F-F05A bulkhead aren't the same length).  The double check of the center hole showing my center and horizontal lines meant it was time to drill.

I probably could have just drilled the bar by hand using the holes in the F-705A bulkhead as a guide, but with the thickness of the bar I was worried about not drilling straight, especially once the next layer of the doubler gets drilled.  I've learned that rivet holes that aren't perpendicular to the surface end up being an absolute bear to rivet.  Of course the same goes for bolt holes.  It was awkward, but I used the drill press to drill all of the holes.

I was worried about the clamps not holding the bar, doubler, and bulkhead solid while drilling through it all, so I split it into two operations.  I drilled all of the holes in the bar first, then used that as a guide to drill the doubler (and spacers).  For reference, this is the bulkhead that will sandwich the ends of the rear wing spar.