Great for deburring and chamfering openings to pre-drilled holes. Great for electrical, plumbing and HVAC contractors. Bosch countersinks cut varied materials cleanly and accurately. Trailing flute automatically deburrs holes. These countersinks perform great in even the toughest materials. Self-starting point starts on contact. Balanced double flute. Eliminates chatter and vibration. Re-sharpenable cutting edge enables longer tool life.