Here we have an ender 3 spool roller bearing, printed in place.
Sick of having the thing jerk and snag and more, so I made a print in place roller bearing, but then went further and created a runner for it to run smoother on, a stop and sprung inserts to go into the spools, all to give you a nice snug roll.
This works better than a metal bearing, they are too smooth, the spool unravels, but this has enough friction to limit that.
The roller turns on its printed bearings, with the runner increasing the diameter of the spool holder and inserts making the spool fit snugly on it all.
Print in place, no supports, no in fill for everything.
Spool roller is print at 20mms walls max speed.
Once printed, creek each wheel to separate and turn until all free.
This may fit other spool holders out there but fits the ender 3 holder perfect so should fit other enders too.
Will fit over a 36mm diameter spool lip, runner making the shaft thicker and inserts fitting various size spools being sprung (2 per spool)
Enjoy