Filament bearing. Fits on 8mm shaft with two 608 bearings (optional).
I made it for my Ankermake M5 after I noticed it dragging pretty hard, particularly with cardboard spools. The picture shows the smaller flange version.
I had to file the end of the steel shaft that came with the printer. There was a bit of a ridge on the end.
The spool halves total to 75mm wide. I left mine separate, but they could be glued together. The 3mm bearing washers keep the spool from rubbing against the arm or previous end stop.
UPDATE: I've been using it for a week or so now. Works perfectly. Much reduced force necessary to pull filament. Planning on making a version for my Creality CR10.
The author marked this model as their own original creation.