Originally Posted by
JBC353
Get yourself a metric dial caliper and start measuring. Ask yourself "In the context of my particular application, what holds the left end of the cartridge?"
The actual measurement of the spindle is a good starting point. With square taper BB's, though the actual place the crank ends up varies with each taper. So, it's not possible to measure this exactly without the BB and crank installed. Then you first get to see how far off you are.