Hi,
I got a ‘70s Campagnolo Record steel bottom bracket but later on I realized threads on the fixed cup were damaged, mostly cross threaded on the three first. Although not expecting much, I tried anyway to reshape them with a thin metal handsaw, then cleaned and greased everything and tried to install the cup on a useless frame. I went by small steps, back and forth, did have to apply some force, not excessively, at the end but eventually got it in. After removal, a couple of small shavings came out. My suspect was that I damaged the frame shell threads, so tried a well functioning cup to check and it also went all in without problems. Tried the damaged cup again a few times and it went in easily to the end, but once not straight. I therefore decided to proceed the same way on another (nicer) frame, but again had to apply some reasonable force before getting to the same situation: damaged and non-damaged cups eventually screwing in easily and tightening. I find it puzzling that both can work, so my question here is: is it more likely the damaged cup threads got to work more or less properly, or that I rather deformed (damaged ?) the frame shell threads? Here are pictures on the four sides of the damaged cup.
Many thanks.
PS: it’s French threading, so unlikely I can retap the BB just the same
