Calibration of 9 steel gauge blocks by mechanical comparison
Project Description
To undertake a comparison of gauge blocks by mechanical comparison.
The gauge blocks selected are of steel material and have nominal values 0.5 mm, 3 mm, 5 mm, 10 mm, 20 mm,41.3 mm, 50 mm, 80 mm and 100 mm. A single point or 5 point calibration will be undertaken on each gauge block by the measurement procedure being currently used at the project participant’s laboratory, taking into account ISO3650. The deviation from the nominal length of each gauge block will be deduced and the associated uncertainty of calibration evaluated (k = 2).
The bilateral comparison will be based on the protocol used for Project 601 with the exception that the variation in length together with its measurement uncertainty should be reported beside the central length.
Final Report 2006-02-22
A bi–lateral comparison of gauge block calibrations by mechanical comparison was undertaken. The gauge blocks selected were of steel material and had nominal values 0.5 mm, 3 mm, 5 mm, 10 mm, 20 mm, 41.3 mm, 50 mm, 80 mm and 100 mm. A 5–point calibration was undertaken on each gauge block by the measurement procedure being currently used at the project participant’s laboratory, taking into account ISO 3650. The deviation from the nominal length of the length of each gauge block was determined and the associated uncertainty of calibration evaluated (k = 2).
The bi–lateral comparison was based on the protocol used for Project 601 with the exception that, as well as the central length, the variation in length together with its measurement uncertainty were reported. The results of the comparison were reported in October 2004 – good agreement was obtained, En values are smaller than 1 (see Table 1 and Table 2 attached).
It is suggested in the future to think about the uncertainty of variation in length, which cannot be evaluated by standard GUM methods since the model function is not differentiable.