Horizontal Spool Holder using BBs as rollers.

thingiverse

Horizontal spool holder because I've got an abundance of bbs lying around that outnumbers my 608 bearings, and those bearings aren't exactly top-notch. Rolling with this setup proves to be way smoother. The extruder finds it incredibly easy to pull filament from this design without breaking a sweat. It's almost like having a lazy susan for filament at your fingertips. I definitely recommend slapping some tape on the bottom just in case, as the spool will get lighter and might want to slide more than spin. You might also want to consider scaling up the nut by 2% in both X and Y directions only, which should make threading a breeze. This design requires three parts to come together seamlessly.