Prepped the floor seat stiffeners then gave them a shot of primer. While the primer was drying, I returned to the flap block mounting. I originally drilled the forward hole in the flap block to #30 to see where the hole would come out the longeron. After assembling the flap weldment and bolting down the blocks (rear hole), I match drilled the F445 flap blocks to the floor skin and longeron with a #30 drill. Then I moved up to a #20, and finally used a #10 per the plans. I removed the flap block assembly, and then the left and right floors. I went over the floors again to make sure all edges were good and smooth, then I deburred all the holes. I used the DRDT-2 to dimple all of the #41 holes in the flooring. I used my deburr tool in a cordless screwdriver to countersink for the 8 nutplate attachments for NAS rivets. At 7:30 it is still 103 degrees—makes primer dry fast, but sure cuts work effiency.