Influence of Rotational Mounting Conditions on Calibration Results and those Uncertainties in Reference Torque Wrenches

Abstract

In the calibration of reference torque wrenches, the influence of various calibration conditions on the calibration results and those uncertainties should be considered for the precise measurement such as less than 0.1 % of relative expanded uncertainty level. In this research, the differences of changing way of rotational mounting positions were examined, where the changing ways by (a) changing the position of sensing element itself (with lever position), (b) changing the position of a detachable square drive apart from the sensing element (main body) and (c) changing the position of sensing element together with the male square drive apart from the female square hole installed in the measuring side of the torque calibration equipment, were compared by using a reference torque wrench (RTW) of rated capacity of 1 kN·m. Unexpectedly, severe differences did not appear depending on those calibration conditions, differing from the case of RTWs of smaller rated capacities.