Pilot Drills

Improve tool life of a deep hole drill by creating a starter hole, also known as a pilot hole, with pilot drills. Drilling a pilot hole 1-2xD in length creates a consistent surface for the next drill to enter without damaging its primary cutting edges or corners. A pilot drill has an equal or larger point angle than the succeeding drill to guide it towards the hole's centerline and prevent "walking". It is also important that a pilot drill has a marginally larger diameter than the succeeding deep hole drill to act as a guide without damaging cutting edges, margins, or corners.