The vast majority of desktop 3D printers in use today use one or more lead screws for the Z-axis ... he’s using a 30:1 reduction worm gear on the drive — keeping the bed in one place if ...
That’s where the lead screw comes in — most lathes have a gear-driven lead screw that can be used to actuate the z-axis ( the one which travels parallel to the axis of rotation). It’s no CNC ...