Drilled for cowling oil door hidden hinge. Reused existing flange, but changed it's orientation. Drilled for Camloc fasteners and fabricated a fluted stiffener to alow adjustment of door shape. Countersunk for solid rivets, both AN426 on the cowl and NAS1097 reduced head types on the door to attach hinge, fluted stiffener, and Camloc. I may also uses epoxy as a bonding agent. The blue piece is an Alclad sheet, roughed-in as a strike plate to be attached later. The Inside View shows two rivets set as keepers that allow partial assembly for alignment before cowling holes were drilled