Turning is a process used to make parts that have axial symmetry. In turning operations the workpiece is spun in a lathe and cut by a stationary cutting tool. Lathes are specialized for milling round objects and can achieve higher tolerances and performance for such operations.

Turning Operations

The following are some common turning operations:


Turning is used to cut both external and internal threads. This is commonly used on such items as nuts, bolts, caps, and and pipe fittings.

Form Turning

In form turning a die with a certain profile is used to impart the inverse profile on the turned part. Both internal and external forms are possible.

Drilling and Boring

By placing a drill bit or boring bar in the tail stock of the lathe, holes can be drilled on the axis of the turned part. This is much more accurate than drilling with a drill press.


Knurling is used to impart a texture on the surface of the part.


Parting is used to separate the workpiece from the stock material.