Ruthex brass inserts
on amazon.
If you don't have brass inserts a 10x4.5 screw woud do too. I suggest heating it with a soldering iron or lighter before screwing it in to prevent cracking on this small part.
the original is still available in the thing files
YAEEK_-_Yet_Another_Ender_Extruder_Knob.stl | 302.4KB | |
YAEEK_v2_-_Yet_Another_Ender_Extruder_Knob_v2_-_with_fixing_screw.stl | 305.1KB |