If your 3D printer filament is not feeding correctly, or you hear clicking coming from the extruder, the ridged feed bolt “hobbed bolt” may have plastic fragments wedged into its ridges that push the filament into the extruder, and may need to be cleaned.  This short video shows you how to clean the hobbed bolt on a LulzBot 3D printer, and may prove helpful in cleaning other 3D printer extruders. Click through for a short video showing you how!