Finally got some Z-axis assembly done and it's actually looking like the damn thing could work even. Only one side done, other side will see some iterative updates.

Rail holders top and bottom:
https://www.dropbox.com/s/gwk1kdnkff...32.19.jpg?dl=0

Frame rail/slide setup. Also supports the Y-beam. Rail slides are replaceable, printed from PETG. Used PTFE spray on the rails to improve the movement, still bit siff:
https://www.dropbox.com/s/i6j2e5o8au...25.27.jpg?dl=0
https://www.dropbox.com/s/7jpn0lxaxu...51.12.jpg?dl=0
https://www.dropbox.com/s/e292po68uz...51.36.mp4?dl=0

Motor coupler, Z-screw and motor mount/leg:
https://www.dropbox.com/s/dihvkjfkyd...07.23.jpg?dl=0
https://www.dropbox.com/s/0rqnvq8r0r...01.41.jpg?dl=0
https://www.dropbox.com/s/zac7e1regd...07.37.jpg?dl=0
https://www.dropbox.com/s/ytivc70i4b...07.52.jpg?dl=0

Assembled on the frame:
https://www.dropbox.com/s/mcikaqyjnw...18.02.jpg?dl=0
https://www.dropbox.com/s/xnab5e5kmy...18.07.jpg?dl=0

Rest of the legs on the frame:
https://www.dropbox.com/s/ihju3xijtc...29.40.jpg?dl=0
https://www.dropbox.com/s/6vhhh7jfzf...48.22.jpg?dl=0
https://www.dropbox.com/s/3idy1yzqzc...48.31.jpg?dl=0

Not detailing the print settings etc. yet, because there will some adjustments.
Things to improve:
- all z-screw side rolls aren't turning, which is bad thing in long term: the roll will wear unevenly and probably cause problems at some point. So to force the rolls to roll, I'll add some teeth on the rolls and z-screw.
- z-screw sections joining: currently using glue to glue the center part, but maybe think something mechanical
- z-endstop placement; probably add a dovetail slot on the z-screw carriage where the endstop or endstop arm can be mounted
- not perfectly happy with the rail frame mount pieces, frame needs some disassembly when installing the rails. Probably good for now though...

I might connect some electronics to see how things work.