Aircraft-length interchangeable-pilot counterbores are sized to meet specific standards in the aerospace industry. Also known as spotfacers, they create a flat-bottomed cavity at the top of an existing hole so that a bolt, nut, or other part is hidden beneath or sits flush with the top of the hole when installed into it. These counterbores have a removable pilot that can be replaced with pilots of different diameters, allowing the tool to be used with holes of different sizes.

These interchangeable pilots are installed on compatible interchangeable-pilot counterbores to keep the tool centered in the hole and ensure a level seat. They can be removed and replaced with pilots of different diameters to allow the tool to be used for counterboring a range of hole sizes.

These interchangeable-pilot counterbores are the standard choice for creating a flat-bottomed cavity at the top of an existing hole so that a bolt, nut, or other part is hidden beneath or sits flush with the top of the hole when installed into it. Sometimes called spotfacers, these counterbores have a removable pilot that can be replaced with pilots of different diameters so that the tool can be used with holes of different sizes.