Brief Description: Riveted nutplates and countersank screw holes.
I primed the top mating surface of the nutplates and the wing spar flanges to protect the areas exposed from countersinking the nutplate rivet holes. Then I used my home made marking jig to draw out the area to be removed. I used a cordless drill turning a countersink with a #30 pilot to remove the black Sharpie markings. I did get some minor clatter until the pilot made contact with the threaded portion of the nutplate, then it smoothed out and gave me a nice concentric countersink. (What do you know, Van's was right!)
Area to be removed is marked
Rough edge until the pilot hole meets the screw hole
