Lined up and drilled rib #4 (leading edge bottom). Final hole sized drilled (#30) lower leading edge all the way across Drilled rest of pilot (#40) holes on lower rear spar, then updrilled to to #30 and final #20. Installed new retension rings on 12' 2x4 that'll hold the skin up to the ceiling so i can work on open wing. Removed all but a few cleco's on lower skin so i can take it off tomorrow to debur and cortec.