This part of ISO 28927 specifies a laboratory method for measuring hand-transmitted vibration emission at the handles of hand-held power-driven wrenches, nutrunners and screwdrivers used for tightening and loosening threaded fasteners. It is a type-test procedure for establishing the magnitude of vibration in the gripping areas of a machine when operating at a specified load. The method has been tested for fastening tasks only. It is intended that the results be used to compare different models of the same type of machine. This part of ISO 28927 is applicable to hand-held machines (see Clause 5), driven pneumatically or by other means, with impact or impulse action, of shut-off, ratchet or stall type, and of all designs — straight, pistol-grip, angle or bow handle. It covers machines with 6,3 mm to 40 mm (1/4 in to 11/2 in) male or female drive output shafts, as well as other geometries. It is not applicable to nutrunners designed to be used only in torque reaction arms.