Industrial-duty versions of twist drill bits are made from various ... need to make a number of overlapping flat-bottomed holes for clearing the bulk of wood out of a cavity.

Twist drill A standard drill bit with two twisted, fluted cutting edges to remove material Wood Flat drill Has a flat face, a pin at the bottom, and two cutting edges. Allows for a flat blind hole ...

To find out how two new drill bits, both designed with self-feeding features that essentially pull the bit through the hole as it spins, stack up against a standard, old-fashioned spade bit ...