SIM.L-S6 final report: calibration of gauge blocks by mechanical comparison

This supplementary comparison concerns the calibration of gauge blocks by mechanical comparison, which is a technique of paramount importance as it is at the highest level in the traceability chain of length for most countries of the American Continent. This comparison is designed to support the submitted CMC claims of these countries. The measurand is the central length of several gauge blocks as defined in ISO 3650 and the circulated gauge blocks were used for two comparisons carried out in two stages: the first stage, SIM.L-K1:2007, Calibration of gauge blocks by optical interferometry (2007-2010); the gauge blocks were also measured by mechanical comparison for those NMI also participating in SIM.L-S6:2007; the second stage, SIM.L-S6:2007, Calibration of gauge blocks by mechanical comparison (2010-2011) for the participants that measured only by mechanical comparison. In this second comparison there were 16 participants, 14 from the Americas, and 2 invited NMIs from other regions. The circulation in the second stage had 10 participants.