CIPM MRA COMPARISON REPORTS
KEY COMPARISON
APMP.L-K3.n01
Angle gauge blocks
Published on 09/06/2026 - © 2026 K. Vacharanukul et al
Citation K. Vacharanukul et al 2026 CIPM MRA Comparison reports 04005
Authors
Ketsaya Vacharanukul National Institute of Metrology (Thailand) (NIMT) Thailand 
Peter Cox National Measurement Institute, Australia (NMIA) Australia
Okasatria Novyanto National Measurement Standard - National Standardization Agency of Indonesia (SNSU-BSN) Indonesia
Nurul Alfiyati National Measurement Standard - National Standardization Agency of Indonesia (SNSU-BSN) Indonesia
Razman Mohd Halim National Metrology Institute of Malaysia (NMIM) Malaysia
Rafidah Rosli National Metrology Institute of Malaysia (NMIM) Malaysia
Faisal Alqahtani 
https://orcid.org/0000-0001-8760-3338 National Measurement and Calibration Center - Saudi Standards, Metrology and Quality Organization (SASO-NMCC) Saudi Arabia
https://orcid.org/0000-0001-8760-3338 National Measurement and Calibration Center - Saudi Standards, Metrology and Quality Organization (SASO-NMCC) Saudi Arabia
Yasser Bin Talha National Measurement and Calibration Center - Saudi Standards, Metrology and Quality Organization (SASO-NMCC) Saudi Arabia
Tong Cong Dung Viet Nam Metrology Institute, Directorate for Standards and Quality (VMI-STAMEQ) Viet Nam
Vu Khanh Phan Viet Nam Metrology Institute, Directorate for Standards and Quality (VMI-STAMEQ) Viet Nam
Anna Fursa State Enterprise "Ukrmetrteststandard" (SE "Ukrmetrteststandard") Ukraine
Yuri Glushko State Enterprise "Ukrmetrteststandard" (SE "Ukrmetrteststandard") Ukraine
George Tang Standards and Calibration Laboratory (SCL) Hong Kong, China
Henry Chiu Standards and Calibration Laboratory (SCL) Hong Kong, China
Yepenov Tilek Kazakhstan Institute of Standardization and Metrology (KazStandard) Kazakhstan
Suyeubayeva Gulaikhan Kazakhstan Institute of Standardization and Metrology (KazStandard) Kazakhstan
Abstract
The APMP.L-K3.n01 key comparison, led by NIMT, involved ten laboratories calibrating angle gauge blocks of 1′, 25′, 3°, and 30°. The study, focused on pitch angle deviation, utilized weighted means for KCRV determination and Birge ratios for consistency checks. Despite artifact stability throughout the 2021–2024 period, the agreement was not entirely satisfactory, as 20 % of the results (8 out of 40) reported |En| values exceeding 1.
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).