Ender 3 large spool adapter

This is a minimal version of a large spool adapter for the Ender 3 (and probably also other models). A minimum amount of filament is needed, yet the result is good. the wheel at the far end of the spool holder is slightly higher than the wheel closest to the main construction, which prevents the spool from rolling off. I used bike spokes (usually 2 mm diameter) but this can be altered. the holes are set at 2 mm, which makes it a bit narrower after printing, but that is intentional, I drill them out with a 2mm drill bit for a snug fit. the wheels itself I drill with a 2mm drill bit too, but I wiggle a bit after drilling, so that the wheels turn smoothly, without jamming. the 2 rings are secured to the shaft with 2 regular rubber bands, wound a few times up and down.