Abstract: A method and an apparatus for detecting machining flaws of machine tools mechanically removing material from surfaces, especially of grinding machines, with the help of which the occurrence of machining flaws can be determined directly during the machining of the workpiece itself. This is achieved as far as the method is concerned in that the force exerted by the tool bit upon the workpiece during the machining process is measured as an “actual or momentary” value. This value is then fed to an electronic data processing unit and is compared there with a “nominal” value stored there and obtained from the processing of an unflawed workpiece, the thus obtained values can be documented and used to identify a flawed product.