Are taper lock pulleys a good choice for ball screws?

[JAZZCNC]

Shouldn't it be possible to auto-square using 2 drivers and adjustable endstops?

Yes and No.?

The problem with using the switches to get the square is you are applying twisting forces on the gantry/linear bearings/ball screw combination causing friction that will very quickly rob power and lead to stalls or missed steps and excessive wear.!.

You need to set the gantry as close to square as possible mechanically ie: loosening pulleys and plates etc so there are no twisting forces on the linear bearings and ball screws. So having setscrews rather than key ways allows you to turn the ball-screw and have it spin in the pulley for fine-tuning because the belt pitch won't allow fine-tuning.

Then if required only use the switches for the very fine tuning.