pilot bit(n = noun.artifact) - a small bit that drills a first hole to guide a larger drill;
is a kind of bit

a bit, airplane pilot, automatic pilot, bar bit, bit, bit by bit, bit field, bit part, blade bit, bore bit, brace and bit, branch pilot, canon bit, center bit, centre bit, chamfer bit, check bit, combat pilot, core bit, countersink bit, cross bit, curb bit, drill bit, drilling bit, every bit, expansion bit, expansive bit, fighter pilot, fippenny bit, fishtail bit, not a bit, parity bit, pilot, pilot balloon, pilot biscuit, pilot blacksnake, pilot boat, pilot bread, pilot burner, pilot chart, pilot cloth, pilot engine, pilot experiment, pilot film, pilot flag, pilot ladder, pilot lamp, pilot light, pilot program, pilot project, pilot valve, pilot whale, pilot wheel, robot pilot, rock bit, roller bit, senior pilot, sky pilot, snaffle bit, spade bit, stunt pilot, test pilot, the least bit, twist bit