I bought a 5kg spool only to find out my printer did not have the capacity to hold a spool with such girth. This spool holder can hold the smallest of spools and could probably hold something wider than the 3kg spool I designed it for.
This requires some hardware 4x Bearings (7mm depth, 22mm outer diameter, 8mm inner diameter) 2x Rods (5mm diameter, 300mm length) (optional) 64x Magnets or 3mm screws (the top and bottom of the Roller mounts can be outfited with these, but does not require them)
For the full Assembly you want to print 4x Roller Mounts 4x Rollers (I printed these with the wide end downwards, and support to hold them, despite them being 45 degree angles, I found this mostly helped for bed adhesion) 4x Bearing Rod Adapter
Don't print the Assembly file, that's for an idea of scale and how to put things together.
Place bearings into the roller mounts (I used a bit of glue, though they should press fit decent enough) Place rollers onto the rods. If they snap, don't worry! The rod is the strength here, just slide em on anyway.
Rod adapters were made a separate part on the off chance my bearings are weird, I got them from a toy store.
You can likely scale down the rollers to make the design smaller, but I wanted a one-size-fits-all solution and I bought these rods for a different project and was stuck with them.