A bit holder rotating with a drill rod executes a radial extending movement which is derived from the rotation of the drill rod. When a stop is reached, a return movement takes place into a position of readiness which is maintained while the drill rod is running. A renewed radial outward movement of the bit holder is triggered by means of a control signal. A preferred control signal is the pressure drop in a coolant and/or lubricant circuit or compressed-air circuit. The plunge-cutting tool makes any number of plunge cuts of identical diameter while the drill rod is running continuously.
