This filament spool holder makes sure your filament spool is rotating smooth and concentric.
It is printed 2 times and each part is inserted into one side of the hole of the filament spool. Then, a rail is inserted through the 2 smaller holes provided by the filament holder.
The rail and the holder itself must be provided separately. This part was made for the ANET A6/A8 filament holder but it can be used for others, too.
SCAD project files are provided for customization. The diameter of the part should be suitable for most filament spools. But the diameter of the rail could be different depending on your setup.
The other long holes in this part are just there to save up weight/material and to make it look cooler.