Lathe center

A lathe centre, often shortened to centre, is a tool that has been ground to a point to accurately position a workpiece on an axis. They usually have an included angle of 60°, but in heavy machining situations an angle of 75° is used.

The primary use of a centre is to ensure concentric work is produced; this allows the workpiece to be transferred between machining (or inspection) operations without any loss of accuracy. A part may be turned in a lathe, sent off for hardening and tempering and then ground between centers in a cylindrical grinder. The preservation of concentricity between the turning and grinding operations is crucial for quality work.