Sometimes it is not sufficient to check torque and rotation angle in order to eliminate faulty connections. For these cases STÖGER AUTOMATION has developed the measuring method GAP Control. Possible sources of faulty connections may be burrs in the screw thread or on the work piece,  measuring or manufacturing tolerances of threads, work piece height or friction in the thread, for example. When self-tapping screws are used in cast metal parts these potential sources of error can easily add up and can’t be monitored adequately with indirect measuring methods.

GAP Control is a system that measures whether the screw head really has contact with the work piece surface. This technique checks not only the depth of insertion and the torque but also the screw head height. Thus the individual depth of insertion in relation to the work piece height is determined. By combining both test methods the probability of errors is practically eliminated.