J Head conversion to 1.75 mm

While sourcing my new 3D printer (see Rostock), I decided for some reason to make it work with 1.75mm ABS filament.

I already had lying around a 3mm J Head MK IV. To convert it for usage with 1.75mm filament, some information is available on this webpage, but I got a much simpler hack working. What you will need :

  • A short length (a few cm) of PTFE tube inner diameter 2mm outer diameter 4mm (look for “ptfe tube 2mm ID 4mm OD” on Ebay)
  • Drill bits, 3mm, 3.5mm, 4mm.

Completely open your JHead, unscrew everything and get the PTFE liner out. It is RED. Hold the liner tightly on a flat surface and drill it using progressive drill bits sizes to a 4mm inside diameter. Then you should be able to push through your own ptfe tubing. Be sure to push it to the end of the red liner, and cut it flush at both ends.

Put everything back into place and… it’s over !
Your J Head can now handle 1.75mm filament !