Dimples and end rib prep

Today started with the pneumatic squeezer and dimpling all of the tank ribs and outer perimeter of the tank skins, then the C-frame was used to dimple the rest of the holes in the tank skins. Then I broke out the fly cutter and cut access openings in the end ribs and drilled the T-411 cover plate and T-407 stiffener ring to the rib. Next, I deburred all of the holes, dimpled the new rivet holes in the rib, and countersunk the rivet holes in the T-407. Riveting the ribs and nutplates to the T-407 came last.