Put an end to your filament end getting tangled up in the loose outer wraps of your spool. Assemble this clip onto your brand new spool and leave it there until the spool is finished. It rides along with the spool while you print, then tuck the free end of the filament into the retaining slot for storage. Because filament always stays threaded through the gap, it never gets the chance to flop loose and get tangled up. It prints up fast, so print one for every spool!
Print one of each part with 0.2mm layer thickness and 0.4mm line width. The two parts click or slide together and the width can be adjusted for your particular spool. The default size works for most ~8" dia. spools, but you should be able to scale the X axis for larger diameter spools.
Keep the filament fed through the slot at all times. When you want to store the spool, just press the free end of the filament into the tapered slot on the side.
This version is for 1.75mm dia. filament only.