the removable cup threads fine on the drive side only and the cartridge on the other but not the other way
Have you checked the handing of both cups and both sides of the shell? Can you start the threads the "right" way round, i.e. is the problem just a matter of not being able to get the cups threaded in to the required depth?
Have you checked the handing of both cups and both sides of the shell? Can you start the threads the "right" way round, i.e. is the problem just a matter of not being able to get the cups threaded in to the required depth?