For the aft round tube of the 716 canopy frame that nests against the panel - countersinking it for the CS-4-4 rivets is going to create a pretty big hole by the time the countersink is deep enough for the skin dimple. I know the pop rivets expand pretty significantly, but that much? Before I screw up a frame I've spend a lot of time getting somewhat right, I just thought I'd verify (I'm pretending the frame fits well at this point - can't wait to see how bad it is after the riveting is done)! Did you just free hand the countersink vs use a cage? I didn't even bother drilling the last couple of outside holes in the tube. I'll be filling that gap with micro and don't know that I'll even put rivets to nowhere in.
