Fuel filler cap fitting

I am using the modified fuel flange plate design - the plate directly against the skin is 2.4mm rather then the supplied 3.1mm. The rear flange plate is countersunk as specified and the original 4x10mm sealed rivets are used. These rear plates are full chamfered, and the fuel filler cap sits directly against these, as discussed in a previous blog. Wood jigs were constructed to hold the filler cap frame against the rear flange plate. The result is the surface of the filler caps are very slightly proud of the skin surface, a nice result.