Monitoring the state of mechanical machine tool components is of growing importance for increasing machine tool availability and reducing inspection efforts and costs. Open numerical controls offer a new opportunity for getting access to signals of drives as well as of the control itself and to integrate the end-user's individual applications. Because the actual drive signals contain information on the mechanical behaviour of the drive chain components, their use for condition monitoring mechanical drive components is a reliable and cost effective approach. The paper presents a new approach on using digital drive signals for a control integrated condition monitoring system to monitor typical disturbances like backlash and pittings on guideways.