Sources and scope for this page: Industry convention — no single governing standard (conventional usage, definitions vary between sources), covering the definition of hard turning. No independent source check is recorded for this page: the content rests on the sources listed and on the working shown on the page. How sources, methods and updates are recorded.
Definition
Hard turning replaces a grinding operation with a single-point cut in the hardened state. It needs ceramic or CBN tooling and a rigid machine, and it can hold tolerances and finishes that rival grinding.
The economics decide it: hard turning is faster and more flexible for complex geometry, but it does not correct distortion the way grinding does, and it can leave a different residual stress pattern on the surface.
Common misuse
Hard turning a part that has distorted in heat treatment. Turning cannot correct the distortion; grinding can, which is often why grinding is specified.