International Standard 8991 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAR OPTAHM3ALMA HO CTAHAAPTM3AUWM+ORGANISATION INTE RNATIONALE DE NORMALISATION Designation system for fasteners Systemededesignationdesélementsdefixation First edition -- 1986-12-01 UDC 621.88 Ref. No. ISO 8991-1986 (E) 0 8991-1986 ( Descriptors : fasteners, designation. Copyright International Organization for Standardizatior Price based on 2 pages d without license from IHS Not for Resale Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through isO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- 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. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. InternationalStandardISO8991waspreparedbyTechnicalCommitteeISO/TC2 Fasteners. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. International Organization for Standardization, 1986 Printed inSwitzerland No reproduction or networking permited without license from IHS Not for Resale ISO 8991-1986 (E) INTERNATIONAL STANDARD Designation system for fasteners 1 Scope and field of application This International Standard specifies a system for the designation of fasteners in product standards. 2 System Denomination (name ofproduct) Reference to the appropriate. International Standard Thread size or nominal size (e.g. diameter) Further diameters or features (e.g. tolerance of pin diameter, if necessary) Nominal length (for bolts, screws, studs, pins, if necessary) Thread length or shank length (if necessary) Type of product (if necessary). Property class or hardness or material Product grade (if necessary) Type of drive (if necessary) Surface protection (if necessary) Copyright International Organization for Standardization No reproduction or networking permited without license from IHS by IHS und Not for Resale