"Phil Kangas" fired this volley in news:ml6ued
:

Perhaps by using, OMG, trigonometry?
Or plane geometry? horror of horrors...
But it may not be accurate to a 0.001 ....

Phil, all these are methods that might be employed, but all depart from
the simplicity of either purchasing a large assortment of v-anvil mics,
or just using the lathe/dro as I did.

And to be clear, the v-anvil micrometers would be almost as troublesome
to use as the lathe, in the case of cutters like wing drills, where you'd
have to rotate the cutter in the anvil, and get a "feel" for when it was
properly seated at the 120-degree points.

Like I wrote before, I was hoping there was some old 'lore' about a Q&D
method of doing this -- but I couldn't find it in the literature, and
nobody's come up with a better way than what we're using, yet.

LLoyd