Parametric simple piston pen for OpenSCAD.

This Pen can be printed on 3D printer requires only o-rings, nib with feeder, a bit silicone grease and some polishing inside.

In default configuration you will need additionally:

1. Nib #6 (Noodler's, Peter Bock, Jowo... whatever you like).
2. Feeder (ebonite) by Noodler's for Ahab/Konrad pens (you can buy it as a spare part) or self-made analog.
3. 2 O-rings (mine came from set of O-rings for 3/8"-1/2" something, ~9mm outer diameter, ~5mm inner diameter and about 2mm thick rings).
4. A bit of silicone grease.
5. Sand paper (400, 800, 1500 in my case) and something to polish inside 9mm diameter.

Printer with 0.4mm nozzle and 0.1mm layer.

After printing body should be polished inside to let o-rings slide by walls and be water-proof. Put o-rings over piston and use a bit of silicone grease to make piston and o-rings move better (prevent grease touching nib or feeder).

You will need this library for threads to build it https://dkprojects.net/openscad-threads/