[dekhn]

I built this stage already (XY with a separate stepper-based Z-stage). I agree, the cost is low, but I found endless problems with the motor to micrometer coupling. Specifically, the torque on the shaft changes quickly during rotation and that led to non-equal spaced steps. My guess is that the shafts I'm using are inferior to the ones they use, but honestly I can't tell (it's hard for me to justify spending $100+ for a cable if I don't know if it;'s going to work). Or, they have a different geometry for the cables.

Since then I've also tried another approach, using a GT2 belt, but the belt deflects significantly at the extent of stage range (50mm). My next attempt is going to be to fix the steppers to the stage itself so that they move witth the stage.