Replaces the PC4-M6 Pneumatic Fitting Push to Connect, which always tended to loosen the Bowden tube.
With this part the Bowden tube now holds bombproof. The M6 thread should not be tightened too much. The nut for the Bowden hose can be tightened to provide a secure hold. Use a second open-end wrench to hold it in place!
05.04.2019: bowden_fitting_m6-101,5p-adapted.stl added - M6 thread is 101,5% thicker for better hold.
M6-distance.stl added in case the tension of the Bowden tube always loosens the M6 connection by itself.
28.05.2019
In case the part breaks off again and again at the m6 thread:
I have now added the file "CR-10 Extruder Coupling.stl". This has to be fixed with a cut off Nozzle Throat (including inner Teflon). This holds now bomb-proof and there is no more breaking!
Ebay: https://www.ebay.at/itm/223267675136
Ersetzt den PC4-M6 Pneumatik Push to Connect Anschluss, der bei mir immer die Tendenz hatte, dass sich der Bowden Schlauch lockerte.
Mit diesem Teil hält nun der Bowden Schlauch bombenfest.…

I modified a M10 coupling to include a stop gap so a separate PTFE tube could be held in the CR-10/Ender 3 hotend.  
Full details in this video:https://youtu.be/Fb4XMbZ0iA4
I added the HotEnd Prop I used in the Video.