Quick Answer: Turning is a machining process in which a cutting tool is held nearly stationary to cut a rotating workpiece. The cutting tool can be slowly moved back-and-forth and in-and-out to cut cylindrical shapes and flat surfaces on the workpiece. Turning is usually done with a lathe. Usually the term "turning" is used for cutting external surfaces, and "boring" for internal surfaces, or holes. Thus the phrase "turning and boring" categorizes the larger family of processes known as lathing. Additionally, "facing" is cutting the ends of the workpiece, to create flat faces. Turning is typically done with either a manual or computer numerical control lathe. With a manual lathe, an operator turns cranks to move the cutting tool. On a CNC lathe, the cutting tool is moved by a computer, controlling electric motors to follow a pre-programmed path. Early manual lathes could be used to produce complex geometric figures, even the platonic solids, though this is now usually done with CNC machines.