Mk 2 Single/Dual Bowden extruder for E3D V6 or Chimera and HK Fabrikator or other RepRap

This is a second take on my previously published extruder design. Although Mk1 worked very well it was a pain to change filament as the tension on the drive was not easy to release.
This overcomes that problem, although the construction is a little more complicated, so I have also made a video. Again, the parts from the original direct drive can be re-used, but if you are making for anything other than a Fabrikator or are making a dual extruder, then you will need to source the following parts