Ender 3 filament extruder knob

This is a knob to rotate the extruder motor by hand. Drill the hole to 2.5 mm and tap for an M3 screw. This gives a more positive grip on the motor shaft.

Tapping the plastic failed over time so changed the size of the spigot to accept a M2 nut insert and use a M2 screw. Glue the nut insert in place for extra screw strength.