Drilled 3/16" bolt holes using hinges as templet. Drlled and countersunk #40 rivet holes for one lug anchor nuts in left flap.
Anchor nut - MS 21051L3 (10-32) Rivets - AN426AD- 3-4.5
One lug platenuts were installed pointed toward center to allow access of the countersink tool. Can not be too close to the wall. Completed squeezing rivets for the flap platenuts. Installed left flap hinges with AN3-3 bolts.