A 420 mm step-gauge with gauge blocks made from ceramics will be calibrated, i.e. the distance of all 22 centers of the position defining surfaces will be measured with respect to the first one ("surface zero"). The deviations of the nominal positions will be deduced. Where possible, the linear temperature expansion coefficient 'alpha' of the step gauge frame will be measured additionally.
The aimed uncertainty u (k=2) is 0,5 µm for the step gauge calibration.