Robert Christy, comp. Proverbs, Maxims and Phrases of All Ages. 1887.

Wedge

A blunt wedge sometimes does what a sharp axe will not.

A knotty piece of timber must have smooth wedges.

Blunt wedges rive hard oaks.Shakespeare.

Knotty timber requires sharp wedges.

One wedge drives another.German, Turkish.

There goes the wedge where the beetle drives it.