Mary mentioned the pivot pin supplied with a quilting ruler tended to hang up on the layers of fabric and batting in the quilt squares she’s been making. A quick look showed the pin bore a remarkable resemblance to an ordinary thumb tack:
I reset the pin shaft perpendicular to the head, grabbed a small brass tube in the lathe tailstock, inserted pin in tube, grabbed the head in the chuck, ignored a slight radial offset, and attacked the pin with fine files and sandpaper:
The lathe chuck seemed the easiest way to firmly hold the head; I rotated the chuck by hand while filing.
Most of the remaining scratches go mostly parallel to the pin, but it really didn’t work much better than before. We decided polishing the pin wouldn’t improve the situation enough to make it worthwhile.
That’s the difference between sharp and keen, which cropped up with the cheap ceramic knife from a while ago. The point may penetrate the fabric, but the shaft can’t get through the tight weave.
She’s now using a scary thin and pointy embroidery pin, having successfully rebuffed my offer to mount it in a suitable base.