Spool winder

Nothing too fancy here…while there are multiple similar holders/winders, they are

a) just a simple unreliable cone or

b) overcomplicated, with multiple parts and stuff. 

I used the same design and shape widely applied here, so it should be basically considered just a remix. But here you simply need to print 2x the same part and get M8x110-120 screw with hex head and a corresponding nut for an axle. It should fit most of commonly used spools. Do not forget to mount and spin in a direction of tightening to avoid constant interruption of winding (which you'll have plenty anyways). Pictures should be self-explanatory. 

To make it durable and not just a one-time gadget, there are multiple settings pre-applied in the 3mf file, regarding supports, perimeters and such. I highly recommend to use that. And as always, use PrusaSlicer/SuperSlicer.

Word of advice, do not rewind a filament unless absolutely necessary like some case of disaster with the original spool. It's incredibly and surprisingly tedious work if you want to have tidy coils and quite a lot of dust gets accumulated because of static.