Drill bit

Drill bits are the cutters of drill tools. Bits are interchangeable, meaning that they can be removed from the end of the drill, either to replace a worn part or to change the size of the part.

Center drill

Center drill bits are used in metalworking to provide a starting hole for a larger sized drill bit, or a conical indentation in the end of a workpiece to mount a lathe center . These centers are used when turning or grinding workpieces. A workpiece machined between centers can be safely removed from one process (perhaps turning in a lathe) and set up in a later process (perhaps a grinding operation) without losing any concentricity.

Related Topics:
Metalworking - Lathe center - Grinding

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Traditional twist drill bits may tend to wander when started on an unprepared surface. Once a bit wanders off-course it is difficult to bring it back on center. A center drill bit provides a good starting point as it is short and therefore has a reduced tendency to wander when drilling is started.

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The small starting tip has a tendency to break, and it is economical and practical to make the drill bit double ended.

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