A numerically controlled machine tool for machining a workpiece, said machine tool comprising: - at least one work spindle, - at least one feed axis (X, 111; Y, 112; Z, 121), and - a device for collision monitoring on said machine tool; wherein said device for collision monitoring comprises: - a collision sensor mounted on a machine part of said machine tool and configured as an acceleration sensor, - a collision detection means (220, 290) configured to detect a collision of machine parts (130, 140, 152, 150) of said machine tool when a measured value detected by said collision sensor exceeds a predetermined maximum collision limit value, and - a signal output means configured to output a stop signal for stopping said at least one work spindle and said at least one feed axis (X, 111; Y, 112; Z, 121) of said machine tool when said collision detection means detects a collision, and a means (240; 170; 190) for setting the collision limit value on said machine tool, said machine tool further comprising a vibration monitoring means configured to monitor a vibration on said at least one work spindle based on the measured value as a function of time detected by said collision sensor configured as acceleration sensor, wherein said vibration monitoring device is configured to perform, based on the measured value as a function of time detected by said collision sensor configured as acceleration sensor, a bearing check of the spindle bearings during operation of said work spindle without an inserted tool, wherein said device (240; 170; 190) for setting the collision limit value on said machine tool comprises a setting means configured to enable setting a plurality of settable collision limit values by an operator of said machine tool, wherein said means (240; 170; 190) for setting the collision limit value is further configured such that the settable collision limit values are settable in a range smaller than the predetermined maximum collision limit value, wherein said device for collision monitoring is configured to trigger a machine stop of said machine tool, including a stop of all the axis drives of the feed axes and the work spindles of said machine tool, when the measured value detected by said collision sensor exceeds the maximum collision limit value, and to trigger a different reaction when the measured value detected by said collision sensor exceeds one of the settable collision limit values, wherein said setting means is configured such that it is possible for the user of said machine tool to set which reaction is to be triggered on said machine tool in the event that the measured value detected by said collision sensor exceeds a respective settable collision limit value, such that different reactions can be set for each range between two collision limit values, wherein the reactions settable by the user comprise a warning to the user by a visual display and/or by an optical warning signal, a feed stop including a stop of the axis drives of the feed axes while the spindle drives of the work spindles continue to operate, a feed stop including a delayed stop of the spindle drives of the work spindles, an automatic tool change, and a quick stop of the axes and spindles of said machine tool using additional braking means, wherein the device for collision monitoring further comprises a collision limit value data storage means for storing collision limit value data indicating tool-dependent collision limit values for a plurality of tools, wherein said means (240; 170; 190) for setting the collision limit value is further configured to automatically set the settable collision limit values during a tool change on said machine tool based on the collision limit values to be set for the substitute tool indicated in the limit value data, and wherein said vibration monitoring means is further configured to automatically perform a bearing check after a startup of said machine tool after a stop of said at least one work spindle and said at least one feed axis (X, 111; Y, 112; Z, 121) of said machine tool when said collision detection means has detected a collision. - at least one work spindle, - at least one feed axis (X, 111; Y, 112; Z, 121), and - a device for collision monitoring on said machine tool; - a collision sensor mounted on a machine part of said machine tool and configured as an acceleration sensor, - a collision detection means (220, 290) configured to detect a collision of machine parts (130, 140, 152, 150) of said machine tool when a measured value detected by said collision sensor exceeds a predetermined maximum collision limit value, and - a signal output means configured to output a stop signal for stopping said at least one work spindle and said at least one feed axis (X, 111; Y, 112; Z, 121) of said machine tool when said collision detection means detects a collision, and