Hello. The fixed cup of my BB was not sitting flush with the frame and had the appearence of being cross-threaded (though it wasn't, since it hadn't been removed and re-installed for years and wasn't always sitting wrong like that).
I finally got it removed by welding some nails to it and using them for leverage, plus plenty of WD40 once I got a bit of movement:
Upon inspection, it is pretty clear what had happened to the fixed cup. Look at the first pass of the thread from the outer edge of the cup:
The threads in the BB shell, on the frame, don't look nearly as bad, but I wonder if there might be any damage?
What do you reckon? Might I run into trouble screwing in a new BB, and/or risk it not sitting in securely enough?