Does the stepper motor turn the middle metal bar and the nut the moves along and the guides keep it level? or am i way off?

David

I'm not completely sure of your question but I'll post this. Level and alignments are handled by guides. All kinds of methods are utilized, pipe and skate bearings, metal angle and skate beatings, drill rod, metal tube, and true linear shafts and bearings. Probably the vast majority of drive from motors, stepper or servo are motor shafts coupled to threaded rod for rotational movement with a fixed nut on the axis mechanical to convert to linear motion.

I think i understand.

On each axis there are two guides either side with ball barings on a L-plate. The centre threaded rod is attached to the stepper motor, on the rod there is a nut fixed to the platorm/table. as the motor makes the step the rod turns, and the table moves in the appropriate direction. ???

is this right

Yes

Thanks Very much i understand how the machine works now. Thanks