Edit 2018-07-20: I had the issue, that the filament gets loose while printing due to the low friction of the bearings. A made a new design that uses axial bearings to prevent that: https://www.thingiverse.com/thing:3012614
It works perfect for me. So i wouldn't recommend this design anymore.
I really like the design by rowokii, but i thought there was room for improvements. That's why i made this.
- added a cutout for a second bearing at the top
- lowered the height from 3 cm to 2 cm (3 cm are not really necessary)
- added a cut around the holder to prevent sharp edges
- added variable number of cutouts as seen in the design by lynspm
- changed the shape of the cutouts to an elliptic cylinder to minimize the sharpness of the edges
- increased the diameter to 8cm (this was necessary for a spool i own, it's on the photo)
- added a thread to the clip to get a good grip on a threaded rod
- smoothed edges on the levers of the clip
- changed the dimensions of the washer to match the bearings
- two printed spool holders (support needed)
- a printed clamp and a printed washer (to tight it against something)
- or two clamps (to tight it in the middle of a rod)
- 4 608 bearings
- a M8 threaded rod (mine has 11 cm)
- a holder for the rod (i use the one for 2020 extrusions from the Hypercube)
For the clamp thread i use this library: https://www.youmagine.com/designs/openscad-metric-nut-bolt-threads-library
It works really nice. The holders turn nicely on the bearings and the clamp holds it firm. I use it in my Hypercube build. The spool holder from the Hypercube accessory pack was to small and the stepping was more annoying than helpful, thats why i looked for alternatives.
Edit 2018-05-05: Added a optimized clip with a chamfer at the top, to be sure it only touches the inner part of the bearing.