There is a lot of drilling that goes on here and then you counter sink all the spots where the AD3 rivets will go, followed by couinter sinking the individual #8 and #6 screw holes, anyway, one half is done, onto the tie down brackets.
Spar drilled to #40 and counter sunk
Close up of counter sinks
Counter sinks etch primed using a brush and nut plates for #8 screws riveted on