This is a fountain pen that uses a Jowo #6 nib unit & Standard International Cartridge/converter. You will have to purchase those separately. I recommend the Opus 88 units available from JetPens, but any Jowo #6 housing should work.
I have provided a clipless version of the cap with a nib shaped rollstop in addition to a clipped version. The clip is installed with one M2.5 flat head screw 6mm long such as McMaster-Carr part 92010A016
I like to chase the threads with a M7.5x0.5 tap. It helps if you're printing with an Ender 3. With a printer like the Bambu, when I tested it, no tap was needed.
Tough PLA works best as regular PLA can be brittle.
Print with a 0.4mm nozzle max. Adaptive layer height down to 0.1mm because there's fine detail on all of the parts. Your printer needs to be well-calibrated to print this accurately.
I like to run the calibration cube here before I run a set of pens to check my flow. https://www.printables.com/model/81314-flow-calibration-cube
Print all parts with the largest flat face down and use a brim on all except the clip. No support should be necessary.
Print them one at a time for the best result to reduce stringing. You will need to deburr/chamfer the bottom edge with a sharp knife or sandpaper just to ensure a proper fit and removal of the brim.
Because the print will still be somewhat porous and not seal as well as a traditional resin, I've found that Private Reserve Infinity Inks work best. Dipping the section to fill is not recommended since the section will absorb and stain. I prefer to syringe-fill converters or use cartridges.
This is a new model based on the design of my Fountain Pen Revolution design
https://www.printables.com/model/491415-fountain-pen-fpr-6-unit
UPDATE 2024-07-11: Added a cap without the rollstop because it didn't render well on some printers.
The author marked this model as their own original creation.