Today I finished match-drilling the 3/16" holes on the bottom spar cap and the bottom flange of the front spar. Then I clecoed the spar doubler in place and put some masking tape over several holes to be drilled later: (a) the holes specifically marked in the plans, and (b) the 9 holes on each side for the left and right attach brackets. (I ordered some machined parts for those location from Rivethead-Aero, but they haven't arrived yet, so I'll have to mount them later.) When the doubler was mounted, I match-drilled the #30 and #12 holes and then countersunk the 8 holes in the diamond-shaped pattern in the very middle of the spar. Afterwards I match-drilled the 9 middle holes on both flanges with a #40 reamer and then countersunk for 3/32" flush rivets.
