Prusa MK4 Filament Guide & M10 pneumatic fitting adapter

Heyho

I have two designs here.

The first is to prevent the filament from being pulled over the metal thread. The M5 -> M10 adapter is for people who don't have a suitable M5 pneumatic fitting at hand but, like me, have lots of M10 versions lying around.

Obviously there is not much space left between 1,75 mm filament + tolerance to the M5 thread. 
Therefore it is very important that this adapter is printed as high quality as possible and with a good layer adhesion. If it breaks off, you have to carefully unscrew the plastic thread. To feel good I tried to break off the small M5 thread of the printed parts with a lot of force. But I didn't manage it :)

I printed them with ASA 0,15 mm layer height & 0,4 mm nozzle. PETG or similar materials that are a bit more temperature resistant will certainly work well too!

Have fun and keep pritnin!

Alternative solutions

The most obvious alternative is to get a pneumatic fitting with a M5 thread and combine it with some PTFE tube.

Or you just put a 1-2 cm piece of PTFE tube around the filament. This should then stay in place in the extruder and prevent friction on the thread.

Instead of a pneumatic fitting, you can also simply feed the PTFE tube directly into the extruder. But that doesn't feel so neat to me :)