DVD / CD stepper slider unit

Inspired by this thing:
https://www.thingiverse.com/thing:1765496
... designed from scratch on Onshape.

I added a second guiding rod. The moving part is guided 100% on one rod and only 180° on second. It can be tightened to second rod with a cable tie. This allows for fine tuning of printing tolerances.
I run a drill bit of 3mm in the guiding holes until they moved smoothly.
3mm guiding rods, stepper motor itself as well as the screws holding the stepper in place are salvaged from old DVD drives.

Two of this assemblies along with a pen lifter (see below) go together to a CNC pen plotter shown in YouTube video.

Designed in Onshape;
public link to CAD - source files attached:
https://cad.onshape.com/document-redirect.html?d=/documents/506d71da1204693ca3d05ba2/w/effb6de1e347e385eb5360d2

See fully assembled CNC - Plotter in action:
https://www.youtube.com/watch?v=xJS5MQ620vE

Goes together with this design:
https://www.thingiverse.com/thing:2746210