Brief Description: Finished wing spar countersinking and made jig.
I finished countersinking all the nutplate rivet holes in the wing spar flange. Then I deburred them all on both spars. I have read on the forums that the optimal outside diameter of a countersink for a number 8 screw is between 0.365" to 0.375" So I made a simple jig from some thin plastic and used a Uni-bit to drill a 3/8" hole in it. I installed a couple of AD3 rivets on either side as guide pins and used it to draw a circle around the screw hole with a black Sharpie marker. The idea is to countersink until all the black is gone. Next up is to prime the spar flange and rivet on the nutplates.
