Unique conical pilot countersink. Conical pilot seeks and finds the center of the previously-drilled hole. Live rubber spring prevents cutting until the pilot is seated and pressure is applied to the workpiece. Cutter extends under pressure for chatter-free chamfering and absolutely concentric cuts. Particularly recommended for use on drill presses and turret lathes, where one tool will handle most chamfering jobs. Replaceable high speed steel blades.