Calibration of 8 steel gauge blocks by mechanical comparison
Project Description
At the meeting of EUROMET Contact Persons in 1999, it was agreed to undertake a comparison of gauge blocks by mechanical comparison. The gauge blocks selected are of steel material and have nominal values 0.5mm, 1mm, 2mm, 10mm, 25mm, 50mm, 75mm and 100mm.
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).
Final Report 2009-03-16
The comparison has been inished and the results are available in the KCDB.
The comparison circulation started in April 2001. The artefact circulation was completed in September 2002 after an additional participant, EIM (Greece) had been added to the timetable.
The Draft A report was issued in October 2004 and discussion of the data occurred during the TC-L meeting, leading to preparation of the Draft B report which was issued in February 2005. Another version of the report (Draft C) was then prepared in September 2006 which contained the results in the form of tables of Degrees of Equivalence and En values.
One participant result was corrected (typo) at this stage. It was noticed during the 2006 TC-L meeting that several of the results for variation in length were not aligned with the remainder but these results also showed evidence of mis-interpretation of the measurand.
The pilot and Zbigniew Ramotowski (GUM, Poland) volunteered to make a new analysis of the variation in length results. Thus Draft C.1 was prepared in August 2007 and contained new graphs of results at k=2 uncertainty level, a corrected result for one participant and a re-calculation of the tables of results for variation in length. Some minor corrections were received and an updated report version Draft C.2 was issued in September 2007, together with a supplementary document describing the changes since Draft C. The TC-L meeting discussed the C.2 report and agreed to finalize the report at that time, if no corrections were submitted. No further corrections were submitted and the agreed final version of the comparison report (Draft C.2) was submitted to the WGDM for approval in March 2008.