Hello, I'm new to Esterbrooks, and to vintage pens in general. I just got a lovely restored SJ off of Ebay. It came with a 2668 nib, and when I use it, it's quite scratchy in a weird way: it seems like there's an incredibly tiny "sweet spot" where it will lay down a perfect line, but even the slightest natural tilt when moving one's hand across the page feels paper-gouging sharp. I'm not pressing hard, and my grip is good; I've never had this issue before. Is this a known quality of this size/type nib? Should I (delicately) use a nail buffer, or what? Thanks, ~Dorothy