[QUOTE= Unless of course it was French or Italian threaded, and then it might be tough to get the fixed cup anyway.[/QUOTE]
The OP said it was from a Raleigh-clone Hercules! that means it's Raleigh proprietary threading, i.e. non standard. I can't wait for someone (maybe Velo Orange in a fit of Anglophilia) to make a cartidge style Bottom bracket for Raleigh Proprietary threading. then I could upgrade this Carlton-built Grand Prix Mixte that I just acquired...