Are the various metric thread settings on a metric lathe with a QCGB all actually mathematically exact, or are some of them just very very close to correct?

I have not calculated all of the more common ones, but it appears that at least some may have to be just very close. Correct enough that normal use would never be an issue, but not strictly mathematically correct.

I have not calculated all of the more common ones, but it appears that at least some may have to be just very close. Correct enough that normal use would never be an issue, but not strictly mathematically correct.

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