HP 7475A Plotter: Ceramic-Tip Pen EOL

Ceramic-tip plotter pens draw wonderfully crisp lines:

Eventually, though, the fiber tip wears flush with the ceramic shell, becomes slightly indented, and ceases to make its mark in the world:

As the lady says, “Starting from zero, got nothing to lose”, so I applied a fine diamond file around the tip:

Well, all I can say is it seemed like a good idea at the time.

Alas, even the newly exposed fiber didn’t make much of a mark on the paper and, as you’d expect, the ragged ceramic tip dragged painfully across the paper. I assume the fiber had filled with fossilized dry ink.

A New Old Stock bag of fiber-tip pens emerged from the Big Box o’ Pens while I was flailing around:

I think the “812” in the lower right corner is a date code, most likely early in 1988, so the pens started their lifetime countdown at least three decades ago. They still work, though:

The plotter appeared at HV Open’s Mad Science Fair, because everybody loves a plotter!