We use the phrase on the button to mean exactly in place. The central circle in the house in curling is called the button. Could that be the origin of the phrase?
I checked their origin of “the whole nine yards” to get an idea of their work, and they agree with Dave’s Big List. I’m saving the site for future reference.
Yes, that site appears to have gotten it right. They’ve done a better job than the OED (1993). (I haven’t looked at that site in ages. Good to know it’s still around.)
If on the button is a boxing term, what about on the nose?
There is what appears to be a guess at Dictionary.com: “This term, like on the button, may come from boxing, where the opponent’s nose is a highly desired target. [c. 1930 ]”
Earliest cite OED has for on the nose is this one.
1883 Sporting Life 20 May 1/3 He hit the ball fairly on the nose, sending it clear to the right field fence.
Baseball perhaps? (N. Amer. origin according to OED.) There’s also a separate entry for the horse-racing sense of betting on a nag to win. That has a 1934 cite and seems to be a derivative of by the nose, at least OED lumps them together.
Note that the OED (2003 entry) has a horse winning “by a nose” from 1851. So that form and sense are older and from horse-racing and may have influenced on the nose (it almost certainly had an influence on betting on the nose).
I wouldn’t rule out boxing—antedatings may always be found—but the evidence so far is for the baseball origin.
But the baseball origin is dubious because “nose” makes no sense in the baseball context; it seems much more likely that it is transferred from boxing and a relevant citation will eventually turn up.