ISO INTERNATIONAL STANDARD 965-1 Fourth edition 2013-09-15 Iso general purpose metric screw threads Tolerances - Part 1: Principles and basic data Filetages métriques IsO pour usages généraux - Tolérances - Partie 1: Principes et données fondamentales Reference number ISO 965-1:2013(E) ISO @IS02013 IS0 965-1:2013(E) COPYRIGHT PROTECTED DOCUMENT @IS02013 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form 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 copyright office Case postale 56 · CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyright@iso.org Web www.iso.org Published in Switzerland i @ IS0 2013 - All rights reserved IS0 965-1:2013(E) Contents Page Foreword ..iv 1 Scope .1 2 Normative references ..1 3 Terms, definitions and symbols. 3.1 Terms and definitions 1 3.2 Symbols 1 4 Tolerance system 5 Tolerance positions ..2 6 Tolerance grades ..5 7 Lengths of thread engagement ..9 8 Recommended tolerance classes ..10 8.1 General .10 8.2 Tolerance quality 10 8.3 Preference order .11 8.4 Combination of internal threads and external threads .11 8.5 Coated threads 11 9 Multiple-start threads .12 10 Formulae. .12 10.1 General .12 10.2 Fundamental deviations .12 10.3 Crest diameter tolerances ..13 10.4 Pitch diameter tolerances .14 10.5 Length of thread engagement 15 11 Root contours ..15 12 Designation. ..17 12.1 General .17 12.2 Designation of single-start screw threads .17 12.3 Designation of multiple-start screw threads .19 12.4 Designation of left-hand threads. 19 Bibliography .20 @ IS0 2013 - All rights reserved ii