Filament Spool Sprocket (Quick Change) - Bolt with conical bearing seats

thingiverse

Quick remix with conical rather than flat bearing seats makes printing a breeze and eliminates the risk of seizing the inner ring of the bearing cartridge against the body. This design works just as well for individuals who use it without bearings too. To ensure easy bearing fitment, you might need to scale this model up to 101% or 102% in your slicer depending on the accuracy of your printer. The bores are 22mm but print out to 21.5mm when made with PETG and measured with digital calipers. 10/3/18: A revised version has been uploaded, featuring a few improvements. It was discovered that increasing the ID at the top slightly would impact users without bearings, so it's now corrected. Additionally, the small ridge at the end of the threads is gone.