
Have I ever told you’all how much I love getting questions about pens, paper and the like? This week, I have two awesome questions.
Beth, the reference librarian asked:
I have a new TWSBI 580 with a custom ground nib (pen was purchased with that nib) and at the same time I purchased a second nib (the whole nib unit) also custom ground – I really like both nibs. One nib is obviously in the TWSBI, which is a nice pen, but I would love to put what I call the “back-up” nib in a different pen, preferably one under $100. that uses a cartridge/converter system. I read about nib-swapping all the time but am not sure just which nibs are compatible with which pens. I don’t think the 580 nib unit will fit the TWSBI mini, but if it did I would go with that. (even though the same filling system.) I am nervous about pulling the nib out of the screw-on unit until I know what I am doing. Am I making sense here? Any advice would be most appreciated!

With a little elbow grease I was able to pull the nib out of my TWSBI Mini. The nib is a size 5 (according to the smarter-than-me folks over in the Pen Addict Slack Channel). The only cheap pen I could find that had a size 5 nib was a Pilot Metropolitan. Pilot nibs have a little flange and a groove nicked out to get them to grip the feed that the TWSBI nib does not have. But… the nib does fit into the feed of a Pilot Metropolitan albeit very loosely. I assume this method would also work in other Pilot pens like the Prera or Plumix. So it is possible to use the TWSBI nib in other pens with a little luck but its not the best fit. If I find any other pens that take size 5 nibs with a cartridge/converter system.
As for switching the nibs between a Mini and a 580, that should just require untwisting the nib unit and sliding the grip section off to expose the nib/feed unit. Then they could easily be swapped between the Mini and the 580.

The second question actually appeared in the Pen Addict Slack Channel.I’m sorry I don’t remember who asked but here’s my results!
A member of the group asked if the Esterbrook 9128 fine flex nib was more or less flexible than the Noodler’s Ahab/Creaper.

The Esterbrook 9128 nib is not super flexible but, for a steel nib, it gets some decent variety and it does not railroad like the Noodler’s nibs do. The 9128 is very smooth and easy to get going while the Noodler’s flex nibs require some adjusting in the feed to get the flow going. So, its a bit of the apples-to-oranges comparison since a Noodler’s flex pen is readily available for about $20 and a vintage Esterbrook with a 9128 flex nib is considerably more expensive ($75 and up). If you’re looking for a flexible nib, a vintage fountain pen with a 14K nib will probably be much more flexible or you might want to consider a Desiderata nib holder.