A turning operation involves moving a cutting tool (usually a non-rotary bit) linearly while the workpiece rotates. It is normally called 'turning' when applied to external surfaces, but 'boring' when applied to internal surfaces. In this sense, the term 'turning and boring' refers to a broader family of processes known as lathing. 'Facing' describes the process of cutting faces on a workpiece with either a turning or boring, and could be grouped into either category as a subset.