Cut an approx. 3" x 3" piece of .063 aluminum sheet. Drilled 3/4" hole for lock and slots for anti-rotation lock. Cut slot in cabin door and match drilled lock hole into door. Drilled 4 holes through door and reinforcement sheet of aluminum. Will rivet and bond this sheet to inside of doors.
Installed door lock and door mechanism to check for operation and any interference. May have to trim outer door handle for additional clearance with outside handle.