Leveraging the revised International System of Units: torque from the fundamental constants

Abstract Calibration of tools designed to apply known torques, such as torque wrenches and torque screwdrivers, requires a chain of traceable standards to the definition of the kilogram and meter derived from the revised International System of Units (SI) via physical mass and length artifact standards. We present a detailed description and experimental verification of a device which utilizes the Kibble principle to directly realize torques up to 1 N m. The second generation Electronic NIST Torque Realizer (ENTR_v2) can calibrate industrial torque tools to 0.1 % accuracy or better ultimately traceable to the fixed value of the Planck constant within the revised SI through electrical traceability chains, severing ties to the traditional physical transfer standard artifacts of length and mass.