Pilot hole

In construction, a pilot hole is a small hole drilled into a piece of construction material. Its purpose may be:

1. to guide a larger drill to the appropriate location and ease the job of the larger drill
2. allow for the insertion of another hole-making tool, such as a knockout punch, that will produce the final-sized hole, or
3. locate, guide, and provide clearance for a self-threading screw in wood or plastic to prevent damaging the material or breaking the screw.