You may have one old enough to be pre-Raleigh and thus have the standard British threading. If you still have the headbadge, it will say Birmingham if it is pre-Raleigh, Nottingham if it was produced by Raleigh. By all means try to save the old parts, some of us are always on the lookout for replacements.

What do you plan to do with the old cranks? If this is truly a pre-Raleigh Hercules I may want to take them off your hands.

-G