Try this filament guide to keep your filament tight on the spool when your print gives it slack. There are two versions- one allows you to add your own 1/4" tubing, and the other has a 3/16" hole that should work without the tubing. The no tubing version may work better if you ream your hole with a 3/16" drill bit before use to smooth out the inside of the hole and reduce friction.The lock clip goes on easiest if you turn it on an angle to get it started over the top slot.I recommend printing this at 40% fill or higher. Use supports everywhere to make sure the slot for the lock clip prints cleanly.