Calibration of parallel thread gauges (APMP.L-S5.2.n01)

Main text The results of the inter-RMO key comparison APMP.L-S5.2.n01 on the calibration of parallel thread gauges are reported. Four National Metrology Institutes from two different metrological regions all over the world participated in this comparison which lasted one year, from January 2019 to August 2020. The artefacts include four thread gauge plugs and three thread gauge rings. Thread angle, thread pitch, simple pitch diameter and pitch diameter were measured. Pitch diameter and simple pitch diameter measurement results have good consistency. In the comparison profile scanning method and two-ball stylus method were used. It was found that the measurement results between the two methods were quite different for thread gauge with a poor tooth profile. To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/ . The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).