Final report on EUROMET Key Comparison EUROMET.L-K7: Calibration of line scales

The results of the EUROMET key comparison on line scales (EUROMET.L-K7) are reported. The comparison involved measurements of thirty measurands ranging from 0.1 mm to 100 mm on two glass scales. Each glass scale circulated in a separated loop. Thirty participants (20 from EURAMET, 10 from other RMOs) were divided into two groups with two linking laboratories. Participating laboratories have used different measurement techniques, which are normally used for calibration services. The results are in quite good agreement: out of the 900 results reported, 80 were not in agreement (within their k = 2 uncertainties) with the weighted mean values taken to be the key comparison reference values. The results of this key comparison will contribute to the Mutual Recognition Arrangement.