Brief Description: Drill out and countersink nut plate holes
Spent ~ hour verifying instructions, sizes of drill bits (tried #41 drill to keep hole smaller - didn't work because countersink bit is #40)
Determined that nut plate rivet holes are undersized and need to be drilled out / reamed to #40. nut plates are attached using AN 426 AD 3-4 rivets. Going to use reamer and countersink with #40 bit. Drilled out / countersunk first 31 nut plates, 62 holes. Looks good, clean, smooth.
