Piloted Counterbores | McMaster-Carr

Counterboring—Enlarge the top of an existing hole to create a cylindrical-shaped opening with a flat bottom that acts as a seat for the head of a screw or wood plug.

Inch Size High-Speed Steel
Counterbores with Built-In Pilot

Metric Size High-Speed Steel
Counterbores with Built-In Pilot

Oversized High-Speed Steel
Counterbores with Built-In Pilot

Counterbore screw holes in misaligned sheets or layers of material.

Carbide-Tipped Counterbores with Built-In Pilot for Steel

To resist damage when cutting steel, these counterbores are C5 carbide-tipped alloy steel.

Oversized Carbide-Tipped
Counterbores with Built-In Pilot for Steel

Designed for counterboring screw holes in misaligned sheets or layers of material.

Carbide-Tipped Counterbores with Built-In Pilot
for Aluminum, Brass, Bronze, and Cast Iron

C2 carbide-tipped alloy steel has excellent performance on abrasive materials such as cast iron and nonferrous metals.

Oversized Carbide-Tipped Counterbores with Built-In
Pilot for Aluminum, Brass, Bronze, and Cast Iron

Use these counterbores with screw holes in misaligned sheets or layers of material.

Counterbores

Counterbores for High-Profile Rounded-Head Screws

Mil. Spec. Counterbores for Hydraulic Ports

Create contoured profiles for installing hydraulic ports in accordance with military and SAE specifications.

Round-Shank Adjustable-Diameter Counterbores

Counterbore multiple diameters with the same tool—use the set screw to adjust the blades to the diameter you need.

Morse Taper-Shank Adjustable-Diameter Counterbores

This counterbore has a set screw that lets you adjust the blades to counterbore multiple diameters with the same tool.

Counterbore Sets

Inch Size Counterbore Sets with Built-In Pilot

Metric Size Counterbore Sets with Built-In Pilot

Oversized Counterbore Sets with Built-In Pilot

Use these counterbore sets when the screw holes in sheets or layers of material are misaligned.

Changeable-Pilot Counterbore Sets

Change out the pilot to use the same tool to counterbore multiple diameters.

About Counterbores

Counterbores with Built-In Pilot

Inch Size High-Speed SteelCounterbores with Built-In Pilot

Metric Size High-Speed SteelCounterbores with Built-In Pilot

Oversized High-Speed SteelCounterbores with Built-In Pilot