The first time was in a P51. It was rather clumsily struck with a chisel-like tool (I thought maybe side cutters) and just put it down to wanton destructiveness or a very strange accident. I used some 9um grit Mylar to remove the obstruction. The nib now works fine.
The next time, it was a Sheaffer Vigilant with a numbered nib-whose-bottom-profile-is-flat. The slit had been very carefully struck on the underside with a small, oblong drift. I didn't notice the imprint the drift made until I looked for it last night. The slit was nearly closed and I ground the obstruction out of it. The pen is my very best writer.
Just recently, I inherited a Sheaffer Balance Vac Fill. It has a numbered nib-whose-bottom-profile-is-flat. The pen was in very bad shape overall. The slit had been peened heavily enough to actually spread the tines a bit at the point. I ground the bulge out of there and did some major tweaking and now the pen writes very well, if a bit on the wet side.
I didn't notice this pattern until I found it in my pen journal. So what is going on? Is this a modification to make a nib write dryer?
Edited by Paddler, 22 April 2009 - 18:28.