Performance of a stiffened 50 N force comparator referring to a tuning-fork force transducer

A force comparator was developed by adopting a highly stable tuning-fork-type force transducer with 50 N rated capacity as the reference. Its structure was stiffened to reduce the effects of eccentric forces and moments caused by the screw of the force generation mechanism. Strain-gauge-type force transducers were evaluated using the comparator and were also calibrated using a dead-weight-type force standard machine to demonstrate the capability of the comparator. Deviations between the comparator and reference machine results were sufficiently smaller than the measurement uncertainties. At present, major uncertainty components that arose from the evaluated force transducer itself degraded the evaluation capability to a relative standard uncertainty of 1.2 × 10−4. If better force transducers become available in future, it should be possible to improve the relative standard uncertainty to 6.0 × 10−5.