First I set up the table by applying tape, to protect the spars from scratches. After clamping both spars to the table, I taped the gap between the spar flange and reinforcement spar to ensure I kept metal filings out. Then I began to match drill the #40 holes that hold the platenut rivets.
After the match drilling operations was complete (I checked holes off as I went). I then began to countersink. I tested and re tested the countersink on scrap and have it dialed in perfectly.
As extra precaution, I have decided to prime the countersunk holes (The instructions mention to do this on the screw countersinks, but I will also do the platenut rivets as well. I used a q-tip and dipped it in primer)
