Cut out the holes for the aileron drive plate and counterweight assembly for the left aileron. Plans look like they say to cut the counterweight "slot" all the way to the edge of the skin, but if this is done, there will be an opportunity for the hinge to pull inward toward the ribs when riveted, since the skin thickness would be gone. Left the portion of the skin where the hinge would go in order to keep everything the same thickness.
Trimmed the skin to the marked lines with the cutoff wheel and file. Radiused all corners to 1/16". Test fit the counterweight subassembly to ensure the skin fit correctly on the ribs.
It was one of those "measure, trim, measure, trim" nights....
