NTERNATIONAL STANDARD (TSO 678 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION -MEKIyHAPOIHAg OPrAHH3ALIMG HO CTAHIAPTH3ALIHH.ORGANISATION INTERNATIONALE DE NORMALISATION Straight bevel gears for general engineering and heavy engineering - Modules and diametral pitches Engrenages coniques a denture droite de mecanique generale et de grosse mecanique - Modules et diametral pitches First edition - 1976-06-15 ISO 678-1976 (E) UDC 621.833.2 Ref. No. IS0 678-1976 (E) Descriptors : gears, bevel gears, teeth modulus, spacing. Price based on 1 page FOREWORD iso (the International Organization for Standardization) is a worldwide federation of national standards institutes (isO Member Bodies). The work of developing International Standards is carried out through IsO Technica! Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmentai, in liaison with iso, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISo Council. Prior to 1972, the results of the work of the Technical Committees were published as IsO Recommendations; these documents are now in the process of being trans- formed into International Standards. As part of this process, Technical Committee ISO/TC 60 has reviewed ISO Recommendation R 678 and found it technically suitable for transformation. International Standard isO 678 therefore replaces ISO Recommendation R 678-1968 to which it is technically identical. ISO Recommendation R 678 was approved by the Member Bodies of the following countries : Hungary Australia South Africa, Rep. of Austria India Spain Belgium Israel Sweden Brazil Italy Switzerland Bulgaria Japan Turkey Chile Netherlands United Kingdom Czechoslovakia New Zealand U.S.S.R. France Poland Yugoslavia Germany Portugal No Member Body expressed disapproval of the Recommendation. The Member Body of the following country disapproved the transformation of ISO/R 678 into an International Standard : Germany @ international Organization for Standardization, 1976 Printed in Switzerland INTERNATIONAL STANDARD ISO 678-1976 (E) Straight bevel gears for general engineering and heavy engineering - Modules and diametral pitches Modules m Diametral pitches P O INTRODUCTION This International Standard, intended essentially to facilitate - 1 the establishment of series of cutting toois, is not intended 1 20 to prevent the use of any unstandardized module or 1,125 18 1,25 16 diametral pitch, which can always be obtained by using the 1,375 14 tool for the module or diametral pitch corresponding to 1,5 12 1,75 11 the next smaller size given in the table. 2 10 2,25 6 2,5 8 2,75 1 SCOPE AND FIELD OF APPLICATION > 3 6 3,5 5.5 This International Standard specifies modules and diametral 4 5 4,5 4.5 pitches of straight bevel gears for general engineering and 5 4 5,5 3.5 heavy engineering. 6 (9,5) 3 2.75 8 2.5 6 2.25 2 DEFINITIONS1) 10 2 11 1.75 2.1 module : The ratio of the pitch, expressed in 12 1.5 14 0.875 millimetres, to the number r (or the quotient of the 16 1.25 18 reference diameter, expressed in millimetres, to the number 20 1 of teeth). 22 25 0.75 28 32 0.625 2.2 diametral pitch : The ratio of the number to the 36 pitch expressed in inches (or the quotient of the number of 40 0.50 45 teeth by the reference diameter expressed in inches). 50 3 VALUES Preference should be given to the use of the modules and NOTES diametral pitches stated in column 1. The module 6,5 in column Il should be avoided. 1 The module of a bevel gear is determined on the complementary cone. The diametral pitches are given in this International The module and the diametral pitch are defined with respect to the Standard only on a provisionai basis; they will be deleted reference surface. after the pe