263 NTERNATIONAL STANDARD Tso INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKIYHAPOAHAS OPFAHH3AIHH IIO CTAHIAPTH3ALIHIM-ORGANISATION INTERNATIONALE DE NORMALISATION ISO inch screw threads -- General plan and selection for screws, bolts and nuts - Diameter range 0,06 to 6 in First edition - 1973-04-01 UDC 621.882.082.2 Ref. No. ISO 263-1973 (E) Descriptors : fasteners, threads, screw threads, screws, bolts, nuts (fasteners), dimensions, diameters, thread pitch, designation. Price based on 5 pages d without license from IHS Not for Resale 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 Technical 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-governmental, 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 Councit. 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 transformed into International Standards. As part of this process, International Standard ISO 263 3 replaces ISO Recommendation R 263-1962 drawn up by Technical Committee ISO/TC 1, Screw threads. The Member Bodies of the following countries approved the Recommendation : Argentina France New Zealand Australia Germany Norway Greece Poland Austria Hungary Canada Spain eipu Switzerland Chile Colombia United Kingdom Israel Italy Czechoslovakia U.S.A. Denmark Japan Finland Netherlands The Member Bodies of the following countries expressed disapproval of the Recommendation on technical grounds : Bulgaria Sweden U.S.S.R. @ International Organization for Standardization, 1973 : Printed in Switzerland d without license from IHS Not for Resale INTERNATIONAL STANDARD ISO 263-1973 (E) IsO inch screw threads -- General plan and selection for screws, bolts and nuts - Diameter range 0.06 to 6 in 1 SCOPE AND FIELD OF APPLICATION 2.2.1 Series with graded pitches This International Standard tabulates Iso inch screw There are three series with graded pitches. They are headed "coarse", "fine" and "extra-fine", in compliance with threads (except for pipe threads) having the basic profile for triangular screw threads specified in ISO 68, /SO general present practice. purpose screw threads - Basic profile. These terms denote the relative magnitudes of the pitches it comprises both a general plan of the iso inch screw of the three series for any given diameter of thread and do threads and the ISO inch screw threads for screws, bolts not imply any difference in the quality of the threads in the and nuts, the latter being a selection from the former. series. ft contains sizes in the diameter range 0.06 to 6 in, The coarse and fine thread series shall be the first choice for comprising a number of series of diameter/pitch general engineering applications, and they form the selected combinations, together with a system of thread series for the commercial production of screws, bolts and designations. nuts. It remains for each industry to choose for itseif, by means 2.2.2 Series with constant (uniform) pitches of selection among the screw threads of this International Standard, the diameter/pitch combinations appropriate to In addition to the three series of graded pitches, Table 1 its own needs. includes columns of constant pitches which have been selected from the range 4 to 32 threads per inch. Each of 2 THREADS SERIES these series is limited to an appropriate range of diameters. The general plan is characterized by a number of thread series, i.e. groups of diameter/pitch combinations distin- gui