Opened up the aft spar attach holes from 3/16 inches to the final size of 5/16 inches. I first opened them up to ¼ inch using a D size drill and a ¼ inch reamer, then to 5/16 inch using a 7.75 mm drill (which is 2% undersize from 5/16) followed by a 5/16 reamer. Installed the AN5 bolts, washers and nuts.
Clamped the F-863 tank attach brackets to the T-405 angles on the fuel tanks with the flanges of the F-863 against the fuselage. Used a 12 inch #30 drill bit to drill through the holes in the fuselage and through the flanges of the F-863 angles. Removed the angles and opened the holes in the fuselage to #12 using an angle drill and opened the holes in the F-863 angles to using a #12 drill bit. Bolted the F-863 angles in place on the fuselage, clamped them to the T-405 angles and repeated the drilling process for the bottom holes. Bolted the angles back in place.
AN5 aft spar attach bolt
F863 attach angle bolted in place (top bolt is reversed for now)
