What Calipers do I Need?

[Chip Chester]

It would probably be quicker to grind one to fit, starting with the closest too-small size. Dremel grinder with pointy stone wheel, and the part in a real vise, or vise-grip pliers. No hand-held. Contour three lobes and Bob's your uncle.

Since they're hard, springy steel, drilling won't do the job.

Chip