Forstner Bit

A Forstner bit cuts flat-bottomed holes with clean, chip-free edges. The cutting action comes from a rim cutter around the outside and a center spur that keeps the bit on track. Unlike a spade bit (which tears through wood fast and rough) or a twist bit (which makes a pointed bottom), a Forstner bit gives you a precise, clean hole. Common sizes run from 1/4-inch to 2-1/8-inch. They work best in a drill press at low RPM (500 to 1,000) but can be used freehand in a cordless drill with a steady hand. They're slow compared to spade bits, but the hole quality isn't comparable.