If the maximum force arising for a system with push/pull rod is too high, the unit is coupled with a rotary bar drive. A rotary bar driven by an additional motor is situated in the main drive spindle. If both rotational speeds are identical, the tool position on the facing slide does not change. If a rotational speed difference arises, e.g. due to a reduction in the revolutions per minute at the rotary bar motor, the tool position changes.