Bowden Coupling fix modified

This is a remix of https://www.thingiverse.com/thing:4357779

I resized the cylindrical chamber next to the hex portion as well as the spacer portion that goes into the coupling's plastic fitting as they were too small for the my coupling and it didn't fit in.

I then also extended the portion that grips the PTFE tube as mine was still slipping and I wanted to add more friction without adding pressure as that would restrict movement of the filament inside.

I made the screw holes bigger in the one side to allow a self tapping screw to go through with no resistance and made the other side thicker to give it something to bite into.
You can still use a normal nut and bolt if you want to, the bolt just has to be a bit longer than in the original design.

Finally I added another lip that fits on the feeder side of the coupling because I found that there was some movement of the clamp over the coupling itself.

At this stage there is no movement so I am happy.