This is a low-friction spool holder for the Makergear M2.
I made it as an addition to the awesome elevated spool holder by slipshine:
I was having trouble with Ninjaflex & Polyflex not extruding properly, and having adjusted every setting under the sun, I finally realised that the tension on the filament (as the extruder was trying to pull upwards on the half-kilo spool, which was on a standard side-mounted spool holder) was too great nad the flexible filaments weren't feeding properly. I figured an elevated spool holder might fix this. But I also wanted to take it 1 step further and remove as much friction as possible.
So I designed a cylinder that fits standard skateboard bearings (22mm diameter), with a flange on each end to stop the spool slipping off. I mounted it using 2mm thick PLA washers (files included), 1/4 inch threaded rod & 1/4-inch lock nuts x 4.
The cylinder can be printed vertically, but be aware there is some overhang. I manually added some supports in Simplify 3D. I printed it in PLA, 40% infill and it's definitely strong enough to hold a half or 1kg spool.
To assemble just insert one bearing into each end of the cylinder, slide it on to the threaded rod, thread a washer on next, and fix it in the middle with 1/4-inch lock nuts. Tighten the lock nuts until the spool spins freely but doesn't rattle.
I then just placed it across the top of the vertical mounts from slipshine's spool holder which I'd already printed and attached to the side of my printer. To prevent the whole thing sliding off I just added another washer and lock nut on each end.
It's a very low-friction spool holder that so far works really well. The only downside is if there's a sudden lurch of the hotend to the right with a sudden stop, the momentum can cause the spool to continue rolling & feeding out filament , but so far hasn't caused any tangles.
This is version 1.0 I may update it