A combination of both quantities force and torque together are often necessary. Some examples are given in testing ship propellers, or in case of fixing screws. Also in elastic axle bearings both quantities are working and both should be measured while happened together. The measurement equipment in the test rigs should be traceable. Therefore a transfer measurement equipment is needed which is calibrated by similar procedure as it is used.

GTM have developed a primary torque standard which covers the range from 1 Nm to 1 kNm with a single load frame and only one weight stack per direction of operation. The design comprises a double-sided lever, supported on straincontrolled elastic hinges, a binary weight stack of exchange disk design for each direction, mounting accessories for the transducer under test and a counter-torque drive with servo-controller. Compared to conventional types with air bearings and a multitude of several stacks, the chosen design offers distinctive advantages:
Higher reliability of the lever support, less complicated auxiliary systems, easier method of operation, low overall height. Calculations show that the parasitic moment of the crossed hour-glass shaped springs for the lever support can be controlled to less than 10^-5 N·m for a 1 kN·m machine, and that the uncertainty of lever length falls within a 20 ppm band, including the equality of both sides. Using the same principle of elastic hinges, the overall torque range can be increased to stretch from 0.1 N·m to over 20 kN·m, with only two separate load frames.

A new superconducting levitated-mass system is now being developed with the final target of replacing the kilogram in terms of the fundamental constants. Improving the stability of trajectory by means of introducing a superconducting linear bearing is the issue in question for the first stage of this development. The present status of the development, experimental results and further prospects are discussed.

The establishment of national calibration services (NCS) and mutual agreements between the NCS of the different countries (UKAS, DKD, SIT, etc.) have increased the necessity of the dissemination of the unit of force inside the individual countries and of standards harmonisation through continuous international comparison.
In the paper the new primary standards of 30 kN and 1 MN of the CNR-IMGC are described. Results are given concerning: the evaluation of the internal coherence of the machine; the internal comparison in the laboratory; the dissemination of the force unit in Italy.

The measurement of air density is crucial for any high accuracy mass calibration and is of particular importance when comparing weights of dissimilar materials such as stainless steel and platinum iridium. The current limit of accuracy to which air density can be determined is the major source of uncertainty in the dissemination of the mass scale for the majority of National Measurement Institutes.
Until fairly recently the main method for the determination of air density was by calculation from measurements of temperature, pressure and humidity using the equation recommended by the CIPM (Comité International des Poids et Mesures). Recently a number of laboratories, including the National Physical Laboratory in the UK, have developed artefact sets for the direct measurement of air density gravimetrically. This paper describes the development of the NPL artefacts and compares their results with those from the CIPM equation.
NPL have also been investigating alternative methods for the determination of air density including the use of an air refractometer, a vibrating U-tube densitometer and an Aerostat “floating” element device. The development, use and relative merits of these three methods will be described as will their current levels of performance and potential future accuracies. Discrepancies between the calculated value for air density from the CIPM equation and direct measurement by artefacts and the other methods described will also be discussed.