I removed skins on right wing to deburr and dimple ribs and spars. Then I c’sink the skin to spar holes on main spar. I found yet another better way for me to do this. Instead of using high speed air drill, I used an old electric drill with adjustable speed and adjusted the speed to about half maximum. The results were much better than ever. This completed all c’sink of both wing spars. I then deburred the RW ribs.
