A line of rotary stroke bearings is available from Mahr Federal (Providence, RI). Suitable for applications where linear, rotary, and combined movements are required, MarMotion high-precision linear or rotary stroke bearings are frequently specified for high-precision applications such as machine tool spindles and pick-and-place assembly robots used in semiconductor manufacture. The bearings are used in measurement transducers, positioning units, centering and tilting tables, and in other modules that have an influence on the measuring result. They exhibit virtually no backlash, stick slip, or wear.The bearings come paired without play for components including small control elements for placer heads and laser welding technology, as well as blade holders, jigs, or fixtures. The size and form accuracy (roundness and cylindricity) of the microfinished running faces of shafts and bushings is less than 1/3 ISO standards; and only grade 5, sorting class P0 steel balls (DIN 5401 or ISO 3290) are used.