Dead Nuts

Does anyone have an understanding of the origins of the phrase "dead nuts", meaning "accurate" or "perfectly sized". I have come across this phrase in the tool & die industry where it is universally understood. Any ideas in origins? I'm stumped as to even a folk etymology.

Sean

Not familiar with the phrase, but "dead" often means completely, absolutely, as in "dead reckoning," "dead certainty," "dead on." A wild speculation: since the subject is tolerances, the nuts might have originated as naughts (zeroes).