A method of monitoring the setting operation for a blind fastener comprising the step of measuring, as a function of time, an electronic signal indicative of the load being applied to the fastener during the setting operation and, from which, determining a mandrel entry load and associated mandrel entry time from this measured signal and an associated setting time, subsequently determining the time difference between the mandrel entry time and the setting time and comparing this time difference against a predetermined reference time difference associated with that particular fastener type to determine whether the set fastener complies with predetermined acceptable setting procedures.