Device for detecting highly stressed positions in a machining tool with a spindle head and a spindle motor, the device comprising: a measuring unit adapted to acquire measurement values of the spindle head during operation of the spindle unit, the measurement values having a current position of the spindle head; a memory unit adapted to store the measurement values acquired; a stress determining unit adapted to determine an associated stress value for each of the detected positions taking into account the measurement values; and an output unit adapted to at least one of outputting the detected positions with the respective associated stress value, and determining from a total number of the determined stress values at least one high stress value which is greater than the other stress values of the total number, and then outputting the at least one determined high stress value with the position assigned to it.