More countersinking... -Countersunk for flush rivets #30 inboard seat rib angles for floor support angle attach L/R. -Countersunk for dimples #40 holes in the aft mid and aft lower longerons L/R. -Countersunk for dimples #30 the five holes in the tab on the fwd end of the aft lower longers L/R.
Countersinking the flush rivet that attached the floor support angle.
Countersinking one of the longerons.
An aft lower longeron done with the #40 countersinking.
