Prusa spool holder

I was probably just being really picky, but I could not find any spool holders I really liked. And the ones I liked was not designed for my wooden prusa.

Most of the filament spools I have are 20 cm diameter, but I designed the holder so you can move one of the rod in if you have a smaller spool. It takes spools up to 100mm wide.

Note that there are different set of the holders. One named 5_5mm that fits my geeetech prusa i3 wood, and one named 8mm that fits the geeetech prusa i3 acrylic.

As minimum you will need to print the two holders and two spools. It is not absolutely necessary to print the spacers, but it is recommended for the life of the bearings.

Besides from the printed parts, you will also need
* 2 rods. I designed for 8mm rods
* 4 ball bearings. I designed for 608zz, but you can probably find alternatives

Optionally, but recommended some way to keep the bearings in place. The obvious choice is M8 nuts on the threaded rod, but for test I also printed som