Yet another Ender-3 filament spool holder

I too wanted to create a filament holder! :D

This one hangs the spool 90 degrees off the top rail of the printer. See the images for better understanding.

The 4 bearings needed are of type 608 aka skateboard (https://www.ebay.com/bhp/608-bearing).

For the complete assembly you need to print:

- 1x holder.stl
- 2x bearing_axel.stl
- 4x bearing_wheel.stl

Note: Customizer does not work for this because it includes MCAD (https://github.com/openscad/MCAD). At least I think that's the