Timing Belts

[Jonathan]

Am I missing something but, isn't it possible to locate the motor between the two lead screws and fit two pulleys to the motor to drive two belts?

That's tricky with a Nema 23/24 motor since the shaft is not long enough to accomodate two pulleys for 15mm wide belts. You could bolt two pulleys together, so one would overhang on the shaft, but that might be a bit much force for the motor bearings. Adding an extra bearing would sort that, but if you don't have access to a lathe or milling machine that gets tricky.

[boldford]

That's tricky with a Nema 23/24 motor since the shaft is not long enough to accomodate two pulleys for 15mm wide belts. You could bolt two pulleys together, so one would overhang on the shaft, but that might be a bit much force for the motor bearings. Adding an extra bearing would sort that, but if you don't have access to a lathe or milling machine that gets tricky.

Bore 'em out then fix 'em on a common sleeve. The tension on the two belts would tend to cancel out if the thrusts are arranged to be reasonably opposite. The belts don't necessarily need to be the same length so the motor need not be centrally between the leadscrews.

Just my two-penny-worth.

[Jonathan]

The tension on the two belts would tend to cancel out if the thrusts are arranged to be reasonably opposite.

Yes of course, but one of the pulleys is much further from the front motor bearing so there will still be a larger moment load on the shaft. Still, I'm probably being being overly cautious.