Okay I'm so incredibly excited to show this 
The CNC machine is almost ready and here is a short video of the z axis at work, together with a 3d printed pen holding contraption (courtesy of my friend who kindly printed it for me 🥰)
I can't believe it works. Now all that remains is the software part 👀
Credits:
The 3d model used is by tranluan19 and can be found here: https://www.thingiverse.com/thing:5505579
(Part 6)