Brief Description: Z Brackets, Countersinking Skins
I removed the leading edge of the right wing and used the 12" #30 bit to drill the innermost and outermost Z-brackets on the tank assembly. I then removed the tank skin and all of the ribs except the the innermost and outermost ribs leaving those ribs and the baffle connected to the spar. I could then drill the remainder of the holes in the z-brackets using the tank baffle as a guide. I forgot to drill the tank skins to the W-423 joint plate so I had to reassemble everything to get that done. What a pain in the posterior and a waste of nearly an hour before I figured out the easy way to do it. I used snips to cut the tank stiffeners from the angle strip and cleaned them up on the Scotchbrite wheel. I final drilled the skins to the ribs and the stiffeners. I finished the day by countersinking the holes where the skin will get riveted to the baffle.
Drilling the Innermost Z-Bracket
Using the Baffle to Drill the Z-Brackets
Countersinking the Skin at the Baffle Attachment Holes