This part of ISO 28927 specifies a laboratory method for measuring hand-transmitted vibration emission at the handles of hand-held power driven percussive machines with and without rotary action [portable rock drills, plug hole drills, rotary hammers, breakers (e.g. pavement breakers, concrete breakers or road breakers), riveting hammers, chipping hammers, pick hammers or similar]. It is a type-test procedure for establishing the magnitude of vibration in the gripping areas of a machine fitted with an inserted tool bit. This part of ISO 28927 is applicable to hand-held machines (see Clause 5), driven pneumatically or by other means, intended for making holes in hard materials, such as rock and concrete. It is also applicable to breakers intended to work downwards to break hard materials (concrete, rock, pavement, asphalt, etc.) and for hammers intended to work in any direction to perform riveting or chiselling work. It is not applicable to impact drills with direct mechanical impact mechanisms. This part of ISO 28927 is not applicable to jack leg type rock drills and push feed rock drills, which are hand guided (the feed force is not applied by hand, but by an additional device). It is intended that the results be used to compare different models of the same type of machine. NOTE To avoid confusion with the terms “power tool” and “inserted tool”, “machine” is used hereinafter for the former.