Milling machines produce the desired shapes of the work pieces by removing material from them with the help of its rotating cutting tools. Because the milling machines have at least three feed directions, then complex spatial bodies can be prepared. Thus complex parts such as engine blocks or gear wheels are produced with milling machines, but simple jobs such as drilling or reaming precise holes are also possible. In modern machines the axes of motion are often implemented with quite different relationships to each other. Additionally, rotational or moveable tool pieces or work piece holders are also now common.