A machine tool with a generator for generating electrical power is disclosed. The generator has a stator with a coil and a rotor with a magnet. The rotor is capable of moving relative to the stator. An air gap is formed between the rotor and the stator. The stator and the rotor comprise a material with a relative permeability greater than the relative permeability of air and are arranged in such a way that magnetic lines of force of the magnet are guided in a targeted manner with respect to the coil. The air gap between the stator and the rotor is configured in such a way that a large proportion of the lines of force emanating from the magnet are guided by the stator and the rotor.