While it doesn’t qualify as a project, taking less than 10 minutes, I converted my Franklin-Christoph Model 66 fountain pen to an eye dropper. The conversion also wasn’t much of a conversion. Just a little silicone grease around the section threads and a little more around the feed threads just to be safe.
I put in about 3ml of Rohrer & Klinger Blau-Schwarz ink and closed it up. It looks like it can hold about 4ml if I top it off. That’s if my syringe is to be believed. In my opinion this ink is perfect for the pen and I haven’t used any other in it since I first matched them up. Add to to that the fact the the pen always has ink it seemed the perfect eye dropper candidate.
No leaking so far. Now I just have to remember not to absentmindedly open the pen to check for the ink left in the convertor.