In fact, I learned “Engineering Drawing” or what most people would probably call basic draughtsmanship at school.. with paper, and pens, and pencils.. (no, not crayons on slates.. that ended the year before I got there).. and as a result of this I am a bit of a drafting pen nerd. I like my Rorting Isographs and my Staedtler Mars Matics, and I have a small collection of matching compasses (or should that be compassie…) set squares and similar paraphernalia.
The only problem with drafting pens (and some other post stone age writing technology) is that they require ink. They suffer from the same vagueries as inkjet printers. You go to use them and nothing happens. You then clean them, and search high and low for the ink you were sure you had, then head off to the store only to find the only ink they have there, costs more per ounce than gold. Oh sure, it comes in a nice fancy bottle, and it has the Rotring seal on it, but its only ink!
So I thought I’d try a little experiment, despite all of the usual “your pen will blow up, the ink will corrode the very fabric of space and time, and end of the universe will ensue” type advice on the internet telling me not to.
I filled my most beat up old pen with cheap out of date, “top quailitly” Chinese inkjet printer refill ink.
So.. if you happen to notice the very fabric of the universe starting to tear, let me know and I’ll try to apologise profusely just before the universe goes foom…
In the meantime however, I can report that it seems to work just fine. 
Rotring ink is very good quality but you still have to clean regularly. It will be interesting to hear your experience.
David.
I still have Rotring and Staedler pens, compasses, set squares, and similar paraphernalia.
I believe that ink from an inkjet dry very fast so you will have your 0.2 blocked very fast.
[zoomx – Mon Jul 16, 2018 7:45 pm] – I believe that ink from an inkjet dry very fast so you will have your 0.2 blocked very fast.
I read somewhere during my extensive five minutes of research that diluting the inkjet ink, up to 4:1 with water can improve flow if you are daft enough to want to try using it. Other magic ingredients suggested were non-ionic surfactants (i.e. washing up liquid) and isopropyl alcohol. I may give those a try, depending on the results of this experiment.
Apparently using the cheap inkjet ink is the secret, as the more expensive stuff is more likely to clog the pen. As it happens, I only had some old, unused and well out of date cheap stuff to try anyway. 
I have some ink somewhere because my only one ink jet printer, an Epson, has the head clogged too much times so I bought a laser one.
I believe that ink is expensive because few people still use it. I schools here in Italy there is still drawing, simple technical drawings, but only with pencils, as far as I know.
[Pito – Tue Jul 17, 2018 11:45 am] –
Fresh blood with 0.3% of alcohol, 2% of sugar, 1% of cholesterol works best..
Only when I’m writing ransom letters 
For more important matters, like revenge on my enemies influencing the US election or casting spells to win the lottery, I use Dragon’s Blood Ink.
FreeCad + RotRing pen + paper + out of date inkjet ink + 3D printer + cheap ebay Calipers + FreeCad youtube tutorial = RotRing body end cap
The biggest surprise was that the rather crude M10*0.75 fine thread, actually works, despite printing with 0.1mm layer height and 0.4mm nozzle.
I have to confess however that it didn’t work *first* time, because despite carefully noting down all of the diameters very precisely, I then set them all as radius values when I should have halved them first. It took me a few minutes to figure out why my printer was printing the first version twice the size it should be. 
I may pop the freecad files up on Thingiverse if I get a spare moment. As you can see I printed it in a rather appropriate “rot” PLA.
EDIT: “Thing” published -> https://www.thingiverse.com/thing:3009400
as i used a 9H pencil, so they turned out as silolettes.
srp
unfortunately, this video always reminded me the challenges for my printer
i kind of regretted my earlier decisions and sort of think that tronxy x1 is possibly *much* easier to get started with 3d printing
i’m sold the delta print concept initially looking at this video, the Reprap Rostock one of the earliest popular delta 3d printer
https://reprap.org/wiki/Rostock
but i overestimated my own prowess and underestimated the intensity of assembling it
I think you are underestimating your abilities.
How hard can it be? Set aside half an hour each evening for the next week. I bet you have it printing before Monday.
I knew nothing about assembling the Tronxy till I opened the box. It took very little time to put it together, no specialist tools or complex processes were involved, just screwing in some screws, tightening a few belts and neatly running a few wires.
Your delta appears a little more fiddly, but not much.
Furthermore I also knew nothing about FreeCad, slic3r or Cura till I started to play with them. Now I understand the basic concepts and have gone from a paper sketch to a solid object and I am pretty pleased with the results.
Half the fun of all of this is the learning curve. I’m not doing any of this for anything other than my own amusement, so there is no pressure if I screw up, unlike the day job. Nobody shouts about it, schedules aren’t missed, customers don’t complain, budgets don’t over run..
