Abstract
The results of a mechanical comparison of short gauge blocks between twelve laboratories of seven Ibero-American countries plus Spain and Germany are presented. Three sets of five gauges, grade K, calibrated interferometrically by the Physikalisch-Technische Bundesanstalt (PTB) were circulated following three different loops, with a maximum of four laboratories per group. The Centro Espanol de Metrologia (CEM), acting as the coordinator and pilot laboratory, calibrated the three sets of gauges before and after circulation. The central length and the variation in length were measured. The results show good agreement, with some discrepancies which are analysed in this paper, and they give the participants the opportunity to check their technical competence. This comparison is a first step towards the mutual recognition of calibration results and certificates among the countries concerned.