The previous builder had already accomplished quite a bit of work on the main tank covers to include installing the attachment nutplates and the stiffeners located on the bottom of the cover. However, he had not yet prepped the holes in the wing to accept the dimples of the tank cover.
Because the nutplates were already installed, I was not able to use a #30 countersink as the pilot on the countersink hit the nutplates, so instead I used a #40 countersink knowing I will most likely have to touch up a few holes by hand because the countersink would not be exactly centered.
After setting the depth of the cut, I proceeded to countersink all fastener holes in the wing common to the main fuel tank covers.
The next step was to bevel the edges of the tank cover followed by dimpling the fastener holes in the cover itself. The bevel step was accomplished first so my tool would not have any interference with the dimples.
I then tacked the cover into place with a few screws in preparation for locating the fuel tank filler neck.
Fastener holes for Main tank covers
Main tank cover with bevel edges and dimples holes
Main tank cover screwed into place with a few screws
