Mostly-printed Z-axis for Neje 30W/40W laser modules

This Mostly-printed Z-axis for Neje 30W/40W laser modules is a mashup/modification and remix of a couple of designs: Silvester's 3D-Printed CNC Z-axis for Nema17 (Pinshape) and leadscrew/nut from 3DPRINTINGWORLD's Linear Ball-Bearing Stepper Stage V2 (TV).

While this version uses printed linear bearings and raw 5/16" drill rod, 8mm polished rod and LM8UU bearings can -- and should -- be used. Here the Z-axis is being exercised over a 50mm range and should be more than enough to bring the laser beam into perfect focus on various thickness materials. Assembled with a couple of 608 skate bearings, a couple of 125mm long 8mm (5/16") rod, and 3mm machine screws.

The r3 frame is less the tab on the bottom end, and overall shorter, with extra mounting holes on 20mm centers to better fit my machine.

Testing -- https://www.youtube.com/watch?v=qxikYlaJYwo