What is a pilot hole?

A pilot hole is a small hole drilled in material before a screw is inserted or a larger hole is drilled.

Why make a pilot hole?

To help prevent the drill bit slipping

When drilling large holes, the drill can slip or skid across the work surface, causing damage. Drilling a pilot hole with a smaller drill bit first will help to prevent slipping.

When you come to drill the larger hole, your drill bit can rest on top of the pilot hole, which will guide it into the material.

To help prevent the material splitting

When drilling large holes or driving large screws into wood or plastic, the material can split if a pilot hole is not drilled first.

Pilot drill bits

To drill a pilot hole, you need a pilot drill bit. You can purchase pilot drill bits to use in a cordless screwdriver with a hex chuck or a cordless drill driver with a 3-jawed chuck.

Ensure you select the right size pilot drill bit. This will depend on the size of screw you want to insert, or the diameter of the hole you want to drill.

For driving screws

Select a drill bit that is the same width as the screw’s shank. This way, the drill bit will remove enough material to prevent splitting but will leave enough for the screw’s threads to bite into when its driven in. 

 You can check that the drill bit is the same width as the screw’s shank by holding it in front of the screw, and looking to see if they match.

Is a pilot hole always necessary?

Generally, you should always drill a pilot hole unless you are carrying out rough construction with softwoods.