I built a pen from scratch on my new lathe and mill.
Sherline lathes make it very easy to turn tapers on short workpieces, so I started with the bottom end of the pen. After making the initial drill hole through the entire piece, I rotated the headstock and turned the conical section near the pen tip.
There was no sanding here. A steady hand and a sharp tool accomplish this.
After reversing the pieces and making sequence of different size bores (for the various parts of the ink refill), I did a test fit.
Fast forward a few days and a few test cuts, and I’m creating the plunger. This will have a set screw in it to be able to make fine adjustments to the depth of the retractable refill.
In the mill, I’m making a flat face to provide friction against the bolt that will sit in a groove in the upper half of the pen, holding the plunger in place.
Tapping the hole for the bolt requires patience.
Facing off the upper tube of the pen before it can be drilled and tapped.
A 3/8″ thread requires quite a bit of torque, so this process was entirely manual (and slow, and difficult).
At this point, I have far too many threads here. Some will be cut off later.
Now the piece is turned around to drill out the space where the plunger will go.
Milling out the track for the plunger’s bolt.
The fully assembled pen. This was fully functional, but a little bit long. I miscalculated a few things, but fortunately that’s where the set screw came in handy.
I was able to cut a half inch off both halves of the pen, move the set screw, and the whole thing is back together even better than before. Altogether it took about 7 evenings for me to learn the skills and do the work just to make a simple pen.