I finally got all the nut plates installed on the top and bottom flanges on both spars. In total, I installed 120 nut plates.
I finished drilling the countersinks on the top and bottom flanges. The most effective manner in which I’ve drilled the countersinks is the following:
- Drilled holes with the #21 rivet remover tool.
- Drilled holes to #19 with a normal drill bit. The depth of the bit was controlled by wrapping tape around the bit.
- Used a #19 countersink to partially countersink the spar.
- Switched to the #30 countersink
- Deburred the internal edge.
The countersink diameter was measured at .370 inches. This was taken from Brad Oliver’s log.