Today was a day for distraction, so I finished the last of the left fuel tank assembly. The inboard rib access cover gets attached to the rib via flat head screws into nut plates that are riveted to a doubler ring on the inside of the rib. I oriented the cover and drilled all of the screw holes through the rib, the clecoed the doubler ring to the other side of the rib and drilled the nutplate holes.
The rib itself gets dimpled for the nutplate rivets so they are flush on the outside of the tank. This is because the access cover will seal with a gasket and needs a flush mounting surface. The doubler ring is thicker material, so is countersunk. With all of that done and with all edges and holes deburred, I riveted the nuplates and doubler ring to the rib.
The fuel filler cap/flange are already drilled. The plans say to match drill them, but that must be for older parts, because these are already drilled to the final size and match up already.
The filler flange is countersunk on the outside surface to accept the skin dimples. I made a small retaining loop out of scrap aluminum - this will get riveted to the flange and holds the end of the fuel vent line.
Lastly, I lined up the center hole of the fuel drain flange and match drilled the skins.
At this point, the only remaining step prior to actually building the tanks is to deburr all holes and edges, then clean everything up and scuff the necessary parts for proseal adhesion. I can't say that I'm looking forward to the mess of proseal, but I'm sure it won't be as bad as I make it out to be. From what I gather, it'll take many, many days of work to do the tank build.
