ABSTRACT
At these very small levels of displacement it is understandable that variation in the engineering environment can be very significant to the reliability of any reading or indication.
Under favorable conditions, traditional extension measurement with micrometers, dial gages, and ultrasound are all capable of measuring the levels of displacement associated with large diameter bolting. When it comes to shorter, smaller diameters involving bolt loads below 4.0 tons, users have to question the validity of correlating minute bolt stretch with tension. Reliability might be attainable in the lab, but in the engineering environment it is often not realistic. Variations caused by workplace conditions, the operator, and the bolt itself tend to be of greater significance than the capability of the instrument.
