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" für Innenflächen oder Bohrungen. Daher fasst der Ausdruck "Drehen und Bohren" die größere Familie von Verfahren zusammen, die als Drehen bekannt ist. Darüber hinaus bezeichnet "Planen" das Schneiden der Enden des Werkstücks, um ebene Flächen zu erzeugen.
Drehen wird typischerweise entweder mit einer manuellen oder einer
computer numerical control (CNC) 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.