Cannon-Pen (safety-pen)

When I was making my first safety-pen it looked to me a bit like a cannon, so I decide that specially make a pen which really looks like a cannon.

The pen is so-called safety pen, it is first of fountain pens which was not leaking in your pocket (name come from here). They was mass-produced from 1890th to 1940th.

Do not try to fill it if you afraid to get inky fingers, without experience it is impossible (As you can see on photos I forget to put silicone grease on TPU washer and got leaking pen).

It filled with ink by eye-dropper or syringe. When you carry it around cup prevent ink from leaking. To start writing you need to bring the pen in working state. Keep it vertically cup up, unscrew the cup, and rotating bottom retract the nib. When nib retracted it prevent ink from leaking and you can write. Then you put it vertically again and by rotating back remove nib (here is one problem it can spit a bit of ink around, probably design flow) and put cup back.

To build it you will need:

1. nib with 5mm diameter feeder (most complex part, you can find it mostly in old pens, I just bought old rifka modules on ebay, but the same diameter feed & nib was on brocken Montblanc pen and old broken Pelikan pen I bought on flee market)
2. 1mm diameter rod (I have carbon one bought in Conrad electronics supermarkt, but stainless steel or ebonite (as in original pens) will work also)
3. 1mm drill or very precise printer which can print 1mm holes
4. two 3mm/1.5mm o-ring, mine come from huge "Metric o-ring assortment kit" (10EUR on ebay)
5. silicone grease
6. 1.75mm diameter filament cut
7. print or male thin TPU or rubber washer to make bottom water tight, only silicone grease is enouch if you polish it well

P.S. The pen was made when I was switching from FreeCAD to OpenSCAD so most part made in FreeCAD, but improved version of spiral and stand made in OpenSCAD.

P.P.S. Idea of mechanics was taking from old safety-pen, probably Waterman.