I have 2 x-steppers connected with a timing belt on the same controller output. However, each stepper has its own Gecko drive with the step and direction inputs in parallel. Advantage is it never racks or gets out of sync and homing is not needed.
That works absolutely fine but as Gerry mentioned, the 2 motors must be set to the same zero-step angle or you may lose torque instead of gaining. This is however very simple: loosen the belt pulley set screws, turn power for both steppers on so that they hold in the same idle position, set proper belt tension, make sure the gantry is perpendicular, then tighten the pulley set screws.
It assumes that the Gecko drives always power up in the same microstep position (intuitive but Gecko never confirmed that to me). But as mentioned it works on my machine.
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