Makergear M2 bearing spool holder

thingiverse

I made this low-friction spool holder for my Makergear M2 as an addition to slipshine's awesome elevated spool holder: https://www.thingiverse.com/thing:37210. I was having trouble with Ninjaflex & Polyflex not extruding properly, and after adjusting every setting on my printer, I realized that the tension on the filament was too great because my half-kilo spool was on a standard side-mounted spool holder. The flexible filaments weren't feeding properly due to this excessive tension. I figured an elevated spool holder would fix this issue, but I also wanted to take it one step further by removing as much friction as possible. So I designed a cylinder that fits standard skateboard bearings (22mm diameter), with flanges on each end to prevent the spool from slipping off. I attached it using 2mm thick PLA washers (files included), 1/4 inch threaded rod, and 1/4-inch lock nuts x 4. The cylinder can be printed vertically, but there is some overhang. To print it securely, I manually added supports in Simplify 3D. I printed it in PLA with a 40% infill, and it's definitely strong enough to hold a half or 1kg spool. To assemble the holder, insert one bearing into each end of the cylinder, slide it onto the threaded rod, thread a washer on next, and secure 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 placed it across the top of the vertical mounts from slipshine's spool holder, which I had already printed and attached to the side of my printer. To prevent the whole thing from sliding off, I added another washer and lock nut on each end. This is a very low-friction spool holder that works really well so far. The only downside is that 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. However, it hasn't caused any tangles yet. This is version 1.0; I may update it later.