Newer design available: Universal Auto-Rewind Spool Holder!
Filament load/unload issues? MMU2 taking too much space? Not with this Parametric Auto-Rewind spool holder! It keeps filament on the spool during unloading, up to eight full revolutions.
This is a remake of the original Auto-Rewind Spool Holder, but with significant enhancements:
Fully parametric
Default spring size 100mm gives up to eight rewinding revolutions
Metal bearings can be used, but also works fine without any bearings
No tape or zip-ties needed
Compatible with existing spool stands with 8mm axle slots
Spring blades in the hub keep the spool pressed against the backplate for adequate friction and prevention of spool sliding off the hub
Adapter allows to mount differently-sized spools on the same hub
Spacers included to keep hub in place
Spring guard included
How it works:

Enter your spool's inner diameter and width in the parameters for reference spool (you can do that in the Customizer app, link is on this page, or download OpenSCAD yourself).…

Filament load/unload issues? MMU2 taking too much space? Not with this Universal Auto-Rewind spool holder! It keeps filament on the spool during unloading, up to four full revolutions. Video compilation
This is a remake of the Original and Parametric Auto-Rewind Spool Holder, but with significant enhancements:
Slipping point of the clutch can be adjusted in about 15 steps using the dial.
One size fits almost all spools up to 1kg. Inner diameter 30-75 mm, max outer diameter 200 mm, max width 88 mm. Hubs for wider spools can be created with the customizer, same for hubs with narrow diameters. Stand for 3kg spools available here.
Spring (v1 and v1.01) works both ways around: towards the axle and towards the outer rim. Note: flipping the direction requires re-calibration of the clutch tension!
Spring v1.02+ and 3.x are direction independent, can be flipped around without changes in clutch tension. These versions might also be better protected against spring overloading.
If the clutch slips too much then you can put…