For my BL12-24 (BH600, Chester craftsman looka like) I made a 80T gear gear to replace the 40T on the input tom the Norton box. If you can make do the same thing with your Crusader, as Muzzer says, set up for twice the required pitch, and you are away.
Do you have any alternaive gears for the Norton box inmput?
(My BL 12-24 came with 32T and 36T alternatives to extend the range of possible threads, do you have any similar alternatives)?
Howard