nail down, bite one's nails

The Economist

In March, the world’s biggest particle accelerator, the Large Hadron Collider, will reopen for business. The rest of the year will see physicists biting their nails. Either theoreticians will be proved spectacularly right, and experimenters can move confidently on into the verdant pastures of so-called new physics, or they will find out that they do not understand how the universe really workshttp://econ.st/13LORbP

Bring On the Tarantulas
By GAIL COLLINS
New York’s Legislature seems to be doing its best to nail down the distinction of having the worst state government in the nation.

nail down
Establish conclusively, as in The reporter nailed down the story by checking all the facts. This metaphoric expression alludes to fixing or fastening something down with nails. [c. 1600]


Definition of bite one's nails in English:
Chew at one’s nails as a nervous habit:

I used to bite my nails