I've had problems with filament uncoiling over the flanges of the spool, and becoming tangled, especially on new, fully loaded PLA spools. I designed this and printed it to solve the problem. It has three rollers with f608zz bearings that contact the flanges of the spool and prevent the filament from going over the sides. The rollers are tapered at both ends to keep the filament spool centered in the device. It is very easy to pull the filament from the spool because the bearings allow the rollers to turn easily. The upper roller axle fits into slots that allow its position to be adjusted to load and clamp any size spool from about 150 - 210 mm in diameter, and widths up to 120 mm.