ISO INTERNATIONAL 239 STANDARD Second edition 1999-10-01 Drill chuck tapers Cones d'emmanchement pour mandrins de perceuse ISO Reference number ISO 239:1999(E) ISO239:1999(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO committees. Each member body interested in a subject for which a technical committee has been established has liaison with IsO, also take part in the work. sO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization, International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 3. 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 239 was prepared by Technical Committee ISO/TC 29, Small tools. This second edition cancels and replaces the first edition (isO 239:1974) which has been technically revised. @ISO1999 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56· CH-1211 Geneve 20 Switzerland [email protected] Internet Printed in Switzerland ISO 239:1999(E) INTERNATIONAL STANDARD @ISO Drill chuck tapers 1 Scope This International Standard lays down the dimensions of drill chuck tapers and includes two distinct types : a) Morse taper type; Jacobs taper type. b) It includes, for each type of taper, a table giving the dimensions. 2 Interchangeability 2.1 Morse taper type See Figure 1 and Table 1. The tapered portions are identical with the following Morse tapers: No.1, for tapers B6, B10 and B12; No.2, for tapers B16 and B18; No.3, for tapers B22 and B24. The length of each of these tapers is, of course, distinctly less than the overall length of the corresponding Morse small end (e.g. B10) or to the part nearest the large end (e.g. B12). 2.2 Jacobs taper type See Figure 2 and Table 2. Table 2 reproduces and classifies the normal dimensions of Jacobs tapers; they also observe the generally accepted designations, in spite of their somewhat illogical appearance. The range of increasing values for diameter D contains two No. 2 tapers, the first of which is a short taper; between