- Inspected all shop heads and marked rejected rivets. There were more than I liked but they had to be replaced. - On further examination of the squeezer, I discovered the flat anvil was too large a diameter to center the squeezer on to the rivets. This resulted in an off-center squeeze that tended to walk off the rivet and cause a malformed shop head. This made squeezing the rudder brackets very difficult in particular. A little difficult to see but the photos below show some of the problem shop heads. - I subsequently ordered a narrow squeeze set. After drilling out the sub-standard rivets I squeezed replacement rivets without further issue (I'm kind of embarrassed it took me so long to figure this out. I just chocked it up to inexperience when really I did not have my tools configured correctly). - Lesson learned.
