A machine, also called a lathe, which feeds a cutting tool into a rotating workpiece to cut away chips of material. A turning machine may be operated manually or by computer numerical control (CNC) to perform a series of operations. External operations which modify the outer diameter of the workpiece include facing, turning, grooving, cut-off, and thread cutting. Internal operations which modify the inner diameter of a part include drilling, boring, reaming, and tapping.