The reproducibility of the measured diameters of such a spray hole, using sections at intervals of about 20µm and measured five times (a). The reproducibility results are better than 1µm. If these results are compared to calibration measurements (b), systematic errors are seen. The work piece can be calibrated using the currently only suitable microprobe, the Werth Fiber Probe. The calibration uncertainty is in the range of 0.5µm.  The systematic deviations obtained by comparing the measurement results can be used to correct the measurement results of subsequent measurements using autocorrection (c). The residuals are less than 1µm.   To save measurement time only the region of interest, the tip of the injector, can be measured tomographically.  The reference coordinate system can be determined quickly using a tactile probe.