104 that may be realized e g in the form of a pin this coupling section 104 makes it possible to drive the countersinking tool 105 the coupling section 104 may be realized e g in the form of a hexagon such that a torque can be transmitted the coupling section 104 may alternatively also be realized in the form of a recess such as e g a hexagon socket fig2 shows a countersinking tool 205 a first section 201 of which is illustrated in the form of a longitudinal section and a second section 202 of which is illustrated in the form of a side view the countersinking tool 205 features a stop 203 206 that is decoupled from the driven cutting section 204 by means of at least one roller bearing 207 208 once the contact surface 209 of the stop 203 206 comes in contact with the workpiece to be countersunk and or deburred the stop 203 206 comes to a standstill such that scraping or scratching e g on a soft aluminum surface of the workpiece can be prevented the stop 203 206 may also consist of a rod 203 two rods 203 206 or more than two rods rather than a round circular sleeve wherein the stop 203 206 is always decoupled from the driven cutting section 204 of the countersinking tool 205 by means of at least one roller bearing 207 208 regardless of its realization in the form of.