Bowden clamp

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](https://www.thingiverse.com/thing:602481). 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](https://www.t