Decades ago (in the '80s), when talk of out-of-tolerance tuning pins first emerged, I made a plywood jig with an indicator on top and a piece of aluminum angle (to match the thickness of the plywood), centered in the middle. The tuning pin lay in the angle, with the indicator plunger contacting the top side (as yours does). I could then read the diameter along the length of the pin by pulling it through, or any out-of-roundness by rotating it.
I never found anything like a 4/0 in a brand new box of 2/0s. But I quickly decided that if I was going to sort for deviations of ~2 mils, because of inaccuracies in the manufacturer's drawing of the rod stock, I would have to check for out-of-tolerance in each pin, both along its length and, where a deviation occurred, out-of-roundness there. It became a matter too many angels dancing on the body of each of these pins.
I still have my home-made jig, and will post a picture of it.
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William Ballard RPT
WBPS
Saxtons River VT
802-869-9107
"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The Continental Harmony,1774
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