Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2606225.

A simple clamp I designed to prevent the bowden tube at the extruder motor end to move into the coupling more than it should. Designed after Self-centering tapered-thread Z-axis coupling v2. Fits 4mm OD tube.

2019.04.24: Use this only as a first-aid solution. In the long run it will loose tightness, polish inside and eventually not work as intended. I later printed and installed the top side of Tevo Flexible Filament Extruder Upgrade