Craftbot Spool Holder

Sometimes the spool seems to grab the Craftbot hanger rod and get swung off center by the extruder, so I created this. By using a bearing on each side of the rod, the spool is supported and will not swing, but rotates easily. Spools with an ID from 50mm to 60mm should work fine - which includes all the eSun, Monoprice, and CraftUnique filaments I have. To adjust for the width of the filament loosen the rear bracket and slide it on the hanger. The spool can still be easily removed with this in place.

(4) of any 608ZZ bearing should work. Also needs (4) M3x20mm socket head screws and (4) M3 hext nuts.

In the picture of the back of the printer, the bracket nearest the printer is an earlier rev with "elephant ears". This prevented the smaller diameter filament spools from being removed with the bracket in place, so the newer one has "mouse ears" which still work fine to keep the spool from jumping the track.

I originally considered using the ["CraftBot filament roller"](https://ww