A counterbore hole is usually used when the head of a fastener, such as a hex head or socket head capscrew, is required to be flush with or below the level of a workpiece's surface.

Dec 30, 2024 · A counterbore creates a flat-bottomed, enlarged opening so that the head of a screw or bolt can sit flush with or below the surface, while a countersink creates a conical recess for the screw …

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Aug 9, 2022 · A counterbore is a flat-bottomed cylindrical hole that is larger than and coaxial to another cylindrical hole. It is used to provide a flat and recessed mounting surface for mating parts.

What Is a Counterbore? A counterbore is a hole-making tool that enlarges a portion of an existing hole to create a flat-bottomed recess for a screw, bolt, or nut head.

Mar 21, 2021 · A counterbore will create a hole that is flat on the bottom. This will allow the bolt or screw that has a flat underside as opposed to the angled shape of a countersink to rest inside.

6 days ago · 1. Definition Counterboring is the process of enlarging the opening of a pre-drilled hole with a flat-bottomed cutting tool, producing a precisely sized cavity for the bolt or screw head. The original …

Jul 19, 2025 · What is a Counterbore? A counterbore is a standardized tool for creating perpendicular surfaces for fastener heads on non-perpendicular surfaces. In other words, a counterbore hole is a …

Counterboring is the secondary machining process of creating a cylindrical shape at the top of a hole using a counterbore. Counterbored holes are often used to recess socket head cap screws below the …

The counterbore enlarges an existing hole and has a flat bottom, ensuring that the head of the fastener sits evenly and securely while maintaining a common centerline with the initial hole.