The pilot drill bit guides itself through a pre-existing hole in order to increase the diameter. These tools are made from spade bits with an aluminum pilot on the tip. When used with a hand drill the result is a perfectly centered hole.

Flex Coat Pilot Drill Bits are available in 5/16″, 3/8″, 7/16″, 1/2″, 9/16″, 5/8″.