Throughout the world bolts are tightened in accordance with procedures based upon the application of a predetermined torque. However, regardless of the accuracy to which the torque is applied, the actual load present in the fastener can vary by as much as 60%. Factors such as lubrication, thread fits, washer hardness and human error can all contribute to the variability when applying a correct load.

By Ben Walters, Managing Director, Scana UK Ltd, UK