ISO INTERNATIONAL STANDARD 6789-2 First edition 2017-02 Assembly tools for screws and nuts Hand torque tools - Part 2: Requirements for calibration and determination of measurement uncertainty Outils de manoeuvre pour vis et écrous - Outils dynamométriques a commande manuelle Partie 2: Exigences d'étalonnage et détermination de I'incertitude demesure Reference number ISO 6789-2:2017(E) rso International Organization for Standardization @ IS0 2017 HEJIANG INST OF STANDARDIZATION C1 5956617 ed without license from IHS IS0 6789-2:2017(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org PrganizationforStandardization icensee-ZHEJIANG INST OF STANDARDIZRoISQ s1.7 - All rights reserved Not for Resale, 2017/5/11 02:38:00 etworking permitted without license from IHS IS0 6789-2:2017(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. .1 2 Normative references 3 Terms, definitions and symbols 3.1 Terms and definitions . 2 3.2 Symbols, designations and units ..2 4 Requirements for calibration ..4 4.1 Calibration during use .4 4.2 Calibration method. ..4 4.3 Calibration system 4 5 Measurement error .5 5.1 Calculation of the relative measurement error .5 5.2 Exemplary calculations of the relative measurement error .5 5.2.1 Example1 5.2.2 Example 2. ..6 6 Sources of uncertainty ..7 6.1 General .7 6.2 Evaluation of Type B uncertainties due to the torque tool 6.2.1 Scale, dial or display resolution, r Variation due to the reproducibility of the torque tool, brep. 6.2.2 ..10 6.2.3 Variation due to the interface between the torque tool and the calibrationsystem.. ..11 6.2.4 Variation due to the variation of the force loading point, bj. .12 6.3 Evaluation of Type A uncertainty due to the torque tool ..13 6.3.1 General ..13 6.3.2 Variation due to the repeatability of the torque tool, bre ..13 7 Determination of the calibration result .13 7.1 Determination of the relative standard measurement uncertainty, w. ..13 7.2 Determination ofthe relative expanded measurement uncertainty, w ..14 7.3 Determination of the relative measurement uncertainty interval, w" ..14 8 Calibration certificate ..15 Annex A (informative) Calculation example for an indicating torque tool (Type I) ..16 Annex B (informative) Calculation example for a setting torque tool (Type Il) ..25 Annex C (normative) Minimum requirements for the calibration of the torque measurement device and the estimation of its measurement uncertainty .34 Bibliography .41 iii =ZHEJIANG INST OF STANDARDIZATION C15956617 vithoutlicense from IHS Not for Resale, 2017/5/11 02:38:00