After going through multiple spool holders, I gave up on them all and came up with this one.

• Ball bearings make for smoother spinning (and less wear on your extruder!)
• Using only two bearings, and (more importantly) keeping them at the center means MUCH smoother spinning
• M10 bolt easily mounts to almost anything
• Fits Prusament, other spools up to 51mm inner diameter

Printing

• PLA or PETG
• No brim or supports
• 15% infill
• 0.2mm layer height

Construction

Parts

• 2x Better spool holder (download)
• 1x Spool Washer (download)
• 2x M4-25 bolts
• 2x M4 nuts
• 1x M10-100 bolt
• 2x M10 nut
• 2x M10 washer
• 1x M10 spring washer
• 2x 10x26x8mm ball bearing (6000-2RS)

Assembly

1. Print 2 of this model
2. Use a M4 bolt to push each M4 nut all the way through each model's hex hole
3. Push the M4 bolts through each round hole, and screw tightly into the M4 nuts
4. Press the ball bearings into each side of the assembly
5. Firmly attach the M10 bolt to a shelf (bolt - shelf - spring washer - nut)
6. Slide the assembly onto the M10 bolt (bolt - spool washer - assembly - washer - nut)
7. Gently tighten the nut
8. Slide your spool over the assembly
9. (optional) I use a little spring clamp to avoid drift
10. To change spools, just remove the spring clamp