Ender 3/Pro extruder knob that holds on to the hobbed gear

thingiverse

Adding a damper to the extruder motor requires that the hobbed gear be moved up the shaft enough that there is no shaft left for most extruder knobs to grab. This knob grabs on to the hobbed gear instead. The notch in the end of the shaft goes over the grub screw that protrudes further from the gear. There's a cutout for the motor shaft if you want to put this on an unmodified extruder motor. If you're printing in PLA, use extruder-knob.stl, If your prints are dimensionally accurate, use extruder-knob-dimensionally-accurate.stl.