A "pilot hole" is a hole drilled into a wood surface prior to installing a screw. Pilot holes help to:
- Prevent wood from splitting from large screws or when near the end or edge of the board.
- Make installing the screw easier in hard materials, such as oak or maple.
- Improve accuracy by providing a guide (or "pilot") path for the screw to follow.
"Freehand" installation of screws is not always accurate.
When accuracy is essential, a pilot hole can help. Here's a guide for sizing your pilot hole, courtesy the Bolt Depot.