Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3072475.

This is a remix of the joshvv Flexible Filament Extruder Upgrade that I added M6 threads to the inside hole where the coupling attaches to prevent the coupling from popping out when not using flexible filament on the printer.

I had this happen once when printing PLA so this fixes that issue as the coupling screws in very solid now.

Refernce my video for installation: https://youtu.be/az7pysnV_MY