Deburred the aft skins, except for the inboard rows of holes where the root doubler goes, and except for the row along the main spar which hasn't been drilled to final size yet. Put the upper skin on the ribs and clecoed the #9 rib in place to drill the clips for the bellcrank reinforcement channels to final size. Missed that earlier. Removed the upper skin for debur, turned the wing bottom side up and installed the tie down bolt. Clecoed the lower aft skin in place and turned the wing back top side up. Leveled the wing with blocks on the sawhorses. Drilled the forward and aft root ribs to their mount brackets. Clecoed the upper aft skin in place. Marked the leading edge skin 3/8" in from the edge to see when it is tucked under the aft skins by the right amount. Put the leading edge skin in place under the upper aft skin and drilled it to the main spar at the rib locations. Wrapped it under the wing and tucked it under the lower aft skin. Installed 4 cinch straps around the assembly. Started drilling the upper forward ribs to the skin. After a few of these holes, the drill bit broke and cut my finger. End of work for the day. After bandaging the cut, I went back out to see what happened. What I think happened is the rib sprung back away from the hole as I pulled the drill bit out, putting a big bending load on the bit. Need to be careful that the rib is held tightly under the skin. I've been doing this by pressing on the skin just next to the rib in the direction it wants to spring away.
