Filament Spool Holder For 3D Printing Nerd. Very simple yet functional design keeping tension on the spools to keep from print head movement bounce causing the filament to loosen on roll, while allowing the rolls to spin filament off without issue. Using 3d Printed Brackets with a readly availabe 608 bearings used in skateboards and scooters. Also using a 8mm shaft/rod/dowle or 5/16" basically anything that will fit the 608 bearing and be about 4.5" long. Should move along the shelf of filaments without messing with the stored filaments.