Countersinks primarily cut conical or V-shaped edges near the surface of a hole, ensuring a fastener with a matching angle sits flush or below the surface of a given workpiece. They can be used when a protruding fastener causes an obstruction, and additional clearance is needed to mate parts, and/or to deburr drilled/tapped holes. Due to their geometry, countersinks require a minimum hole diameter to use.

 

Haas Cobalt Steel (HSSCO8) countersinks are harder than standard high-speed steel (HSS), and provide better wear resistance and higher hardness. They feature a bright, uncoated finish, and are suitable for countersinking a wide variety of materials.