The Precision Twist 76HA regular-length bit is a round shank, center drill bit made of HSS with an uncoated finish and is used for starting a hole. It is designed for drilling to a depth up to one times the diameter of the drill. It is suitable for drilling into a wide variety of metals and synthetic materials, performing best with steel and cast iron. It is double ended with the same type of cutting edges on both ends.
The 76HA series with a 60-degree conventional point geometry should only be used to start holes; do not go deeper than the diameter of the drill bit. Recommended for use in lathes, this design creates a small starter hole, which guides the follow-up drill and prevents walking. They also create a countersink of 60 degrees. The regular length is the most common and offers a good compromise between reach and rigidity for hole-starting. The uncoated finish helps increase chip flow in soft materials. Spiral flutes with a right-hand twist act as a passageway for chip extraction from the hole and for coolant to enter the hole. The right-hand twist brings chips up and away from the cutting edge.
Drilling, or hole making, is the most common metalworking operation in the world. Twist drill bits are the most common type of drill bit used. Twist drill bits can be used in hand-operated drills, standalone drill presses, or a lathe. They are made to ANSI industry standards, which ensure that drill bits around the world confirm to the same specifications.