Here is a picture of the pipes I've made up to now.
The Mk I pipes extruded only PLA while the Mk II and Mk III extruded ABS.
The Mk III is by far the easiest to make. It starts with a simple screw.
It is amazing to see how this tiny piece of brass easily turns into a nozzle. My new nozzle sharpening tool speeds up the making of the nozzle significantly.
A few tools more and I am ready for mass production. :)