Here's a picture of the inside of the door. The verticle piece is made out of 3/4" oak and has small indentations on each side at the middle to act as a handle.
Also on the hing side, 3 of the screws go all the way through the door and are fastened with nuts countersunk on the inside. The same method is used to attach the hinge to the body.
My 1955 Benroy was also made with 1/2" ply but they added an frame around the inside of the door and opening. This allowed the hinge to be mounted on edge of the door and body instead of on the outside.
