I found my cardboard spools were having a hard time spinning on my new AnkerMake M5, and all the solutions were overly complicated, so I made this.

It can be printed easily with no supports, then slid onto the included m5 spool holder to allow your spools to spin freely.

Print settings don't matter much, but I used .3mm layer height with 20% infill.

Also included is a similar model sized for an Ender 3 spool holder.