Tonight I countersunk a fee holes on the rear wing spars, where the gap seals will flush rivet to the rear spar. it’s about 16 holes in total I think, so not a big job. What took more time was sorting through my countersink cages, swapping out the #30 countersink for a single-fluted bit, and then getting it configured to countersink to the correct depth on some scrap. The single flute is so much nicer than the more common three-fluted bits. It makes a very nice cut and just polishes the hole. It seems to be much easier to avoid chatter or deformation that can sometimes occur with the three-fluted bits.
After countersinking, I primed the holes and touched up the primer on a few other spots on the spar.
