Bolt on Spool Filament Clip/Holder

It clips onto a spool, the filament end goes through a little channel, and the bolt tightens it down. Great for spools that don't have enough holes to thread it through.

Print it standing up like in the photo, without support.

None of my spools are thicker than 5mm, so this works fine for me. If you have some extra thick walled spool of filament, maybe it won't work.

Tolerance is fairly tight, if you're printer is fairly out of calibration, print the bolt scaled down to 95% in X and Y direction only to reduce it's diameter a little.