What is a counterbore?

A counterbore is a type of cylindrical hole that is drilled or machined into a material. It is typically used to create a recessed spot for a fastener, such as a screw or bolt, to sit flush with the surface of the material. Counterbores are often used in woodworking, metalworking, and other industries where fasteners need to be securely and neatly installed.

The size and depth of a counterbore can vary depending on the application. The diameter of the counterbore is typically slightly larger than the diameter of the fastener being used, allowing the fastener to fit snugly into the recess without protruding above the surface. The depth of the counterbore is determined by the length of the fastener and how far it needs to be recessed.

Counterbores are often created using specialized tools such as counterbore bits, which have a pilot tip to guide the hole and a flat bottom to create the recessed spot. They can also be machined using a lathe or drill press. Counterbores are commonly used in furniture making, cabinetry, and construction projects to create tidy and secure fastening points.