I worked on removing the bad rivet from the previous build session today. Unfortunately, I was unable to use an angle drill to remove the rivet since the rib is in the way (doesn’t provide enough clearance) so I used a 12” bit on my palm drill instead. I drilled fairly deeply into the rivet using a #30 bit to try to remove as much of the rivet that was sticking out in front of the rib as possible. When I thought I was getting close to the part itself, I used a punch to break off the rivet head and then angle pliers to bend and break off as much of the protruding rivet as I could (where I had weakened the walls by making them thinner with the drill).
From this point forward, things got harder. There was still a bit of rivet sticking out in front of the hole and, since it had bulged out wider than the hole, I couldn’t just punch it through. I worked on it with the pliers some more (also trying to crush it in) but achieved little success. I also drilled through the center of the rivet with a #40 bit which didn’t help much. I didn’t dare try to drill through the rivet with a #30 bit since the front that was sticking out was not even and would not keep the bit centered. It would also give me little to no clearance in the hole itself.
I ended up using a very small file to very carefully file the rivet stem down. Once it was close to the hole and much more even, I was able to drill it a bit with a #30 bit. This was just enough to free it from the rib itself. Unfortunately, there was a bit of a gap between the rib and the spar which still had a bit of the rivet sticking out from the spar into it. With the rib in the way, I was unable to access this part of the rivet to work on removing it. I think I’ll need to remove the remaining rivet on the center rib (the bottom one) as well as the two rivets in the tail rib so that I can shift the whole rib to the side in order to access the problem rivet. I decided this was enough for today though and left that as a project for next time.