In building a filament spool holder, I kept the following design principals in mind 1: You should be able to change spools without tools 2: Plastic should not rub on plastic 3: It should handle any width of spool with a 52mm internal diameter hole 4: Should take up minimal additional space (especially footprint) of the spool itself 5: Any non-plastic parts should be easily and cheaply purchased anyplace without having to mail-order anything 6: You should be able to position the spool to feed off of the right or left side, regardless of if the spool is non-symmetrical. Non-Printed Materials Needed 3x - 608 Bearings (Standard Skateboard Bearing) 1x - M8 - 9cm Bolt 2x - M8 Washers 1x - M8 Wing Nut The slight tilt of the head keeps the spool on the holder without need for any threaded core or additional parts or high-friction between the spool and the holder itself. UPDATE 1: First print worked well, but the tolerances on the bolt head and bearing for the vertical riser where a bit too tight. Adjusted the SLT file to make the holes for each slightly larger (0.125mm) that should allow a much cleaner fit. Also, the wings on the core seemed a bit fragile, so I beefed them up (increased the thickness by 1mm) to hopefully provide better strength. Printing this time at .3mm / 25% Infill (Full Honeycomb) with support (for the bolt-head hole with 4 Shells in ABS. Version 2 of the Core and Vertical Riser are posted up now. Update 2: Re-printed the core at .2mm / 25% Infill (Full Honeycomb). Much lighter and stronger (especially the reel stop find) - Added picture comparing the first and second versions.Bolt's head is glued into the socket in the top of the base riser. Bearings are pressed into both ends of the Core (one end in intended to stick out a few millimeters) and the hole at the top of the base riser (should also stick out 2 millimeters). The base is pressure-fitted together (use some Acetone to bind the parts together). Put a M8 washer on either side of the core to improve the ability of the bearings to move freely. Hold the whole thing together with the M8 wing-nut. You can tighten to allow the device to spin as freely as you like. A little friction is fine to avoid unwinding as the machine pulls the filament. Printed out at .3mm / 50% Infill with support (for the bolt-head hole with 4 Shells in ABS - Will post up pictures after final all-on-one bed print.