ive been told that my malvern star frames much older than i thought (1960s) and that it has a rare bottom bracket threading which is obsolete now. It keeps coming loose and apparantly there is no solution but to get a new frame with a more contemporary threading… does anyone know another solution or way? i love my frame i dont want another one 
cheers
bump
There are these bb’s that have an expanding shell, it will ruin your threading, check Sheldon brown for more details
dunno if you mean the same thing speedy, but you can get bottom brackets that tighten onto themselves. generally used when your bb shell threads are stripped, but it could work.
a company called yst makes one. “self tightening bottom bracket”