I just bought a Kaweco Aluminum fountain pen and, while it looks and writes well, there's a flaw in the design: the cap takes too many turns to unscrew and it slips off the bottom of the pen when you try to assemble it to write. Since it's metal, it can't sufficiently grip the pen bottom. Worse, since I have big hands, the pen by itself isn't long enough (without the cap stuck to the bottom) to rest in the web of my thumb and index. It works fine with the plastic models.

I've not had any problems with mine --- the cap fits on the back just fine.

Maybe you can slip an o-ring on the back to provide some friction for the cap. A black o-ring would be fairly unobtrusive.


matthew