ISO INTERNATIONAL STANDARD 6788 Second edition 1997-12-15 Assembly tools for screws and nuts - Four-way socket wrenches Dimensions and torque test Outils de manceuvre pour vis et écrousClés en croix-Dimensions et essai de torsion ISO Reference number ISO 6788:1997(E) THS under Not for Resale ISO 6788:1997(E) Foreword ISO (the International Organization for Standardization) is a worldwide preparing International Standards is normally carried out through IsO technical committees. Each member body interested in a subject for which atechnicalcommitteehasbeenestablishedhastherighttoberepresented on that committee. International organizations, governmental and non- governmental, in liaison with ISO, also take part in the work. IsO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 6788 was prepared by Technical Committee ISO/TC 29, Small tools, Subcommittee SC 10, Assembly tools for screws andnuts,pliersandnippers. This second edition cancels and replaces the first edition (IsO 6788:1982), whichhasbeentechnicallyrevised. Annex A of this International Standard is for information only. @ISO1997 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced microfilm, without permission in writing from the publisher. International OrganizationforStandardization Case postale 56·CH-1211Geneve 20·Switzerland Internet [email protected] X.400 C=ch; a=400net; p=iso; o=isocs; S=central Printed in Switzerland inational Organization for Standardization from IHS Not for Resale ISO 6788:1997(E) INTERNATIONAL STANDARD @ ISO Assembly tools for screws and nuts Four-way socket wrenches Dimensions and torgue test 1 Scope This International Standard specifies the dimensions of socket heads, in millimetres, of four-way socket wrenches types 1, 2, 3 and 4 and also lays down test conditions to check the suitability of tool performance. This International Standard applies to four-way socket wrenches for assembling screws and nuts with widths across flats of metric dimensions for trucks and cars. The wrenches are listed under number 21 in IS0 1703. 2 Nomative references revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IsO maintain registers of currently valid International Standards. Iso 691:1997, Assembly tools for screws and nuts - Wrench and socket openings - Tolerances for general use. Iso 1174-1:1996, Assembly tools for screws and nuts -Driving squares - Part 1: Driving squares for hand socket tools. Iso 1711-1:1996, Assembly tools for screws and nuts - Technical specifications — Part 1: Hand operated wrenches andsockets Is0 2236:1991, Assembly tools for screws and nuts - Forged and tubular socket wrenches - Maximum outside head dimensions. Is0 3316:1996, Assembly tools for screws and nuts - Attachments for hand-operated square drive socket wrenchesDimensions and tests. 3 Dimensions The dimensions are given in figure 1 and table 1. The tolerances on wrench openings are those specified in IsO 691 in the "unmachined closed" series. Driving squares are those specified in ISo 1174-1. The maximum outside dimensions of socket heads d are 10 % greater than those given in Is0 2236. Copyright Inte nal Organization for Standardizatior