The potmetal used is part of the problem. It behaves differently under heat than other metals. The largest problem I think is over-tightening of the screws and the fact the Rochester B and BC models only have 4 screws in the first place. I've been told the Rochester boys knew this was a problem right away. Why they continued with the design from 1950 until 1967 is a real puzzle.
Do you want to borrow the jig I made? Please let me know.
