The 4.45 MN DWM has been in use in the NIST Force Laboratory since 1965 and is frequently characterized as the largest deadweight force standard in the world. Thousands of measurements through many force calibrations have been performed over the lifespan of the machine. The machine was the centerpiece of two multi-year, multi-NMI international key comparisons that assured comparability of measurements throughout the world for large primary forces, thus, the 4.45 MN DWM is an international resource that has disseminated force units to a worldwide customer base since its inception and is a source of US national pride in the world of metrology.
The lifting frame of the machine is manufactured of various grades of steel; all force-generating, calibrated mass components of the machine consist of AISI 410 and 416 series stainless steel. The design of the weight stack is described as chain-loading or serial-loading meaning each 222.4 kN (50 klbf) weight in the stack must support all weights below it when forces are generated during machine use. The individual weights are among the largest mass objects ever calibrated.