Ender 3 Spool Bearing Holder - Fast Print, MR105 5x10x4 Bearings

This Ender 3 modification allows the filament spool to turn freely without any drag.

[This version 3 is a redesign that solves both problems of the previous. The stress on the ring is gone, now using a set screw to secure the ring to the tube. The plastic post that held the bearing hub is now replaced by an M5 screw that is supported on both ends, such that the weight of the filament spool cannot deform the assembly.]

It works by supporting two MR105 (5x10x4) ball bearings above the factor