7721 International Standard (ISO INTE RNATIONAL ORGANIZATION FOR STANDARDIZATIONOMEXAYHAPOAHAR OPTAHM3ALMA IO CTAHAAPTM3ALWM-ORGANISATION INTE RNATIONALE DE NORMALISATION Countersunk head screws -- Head configuration and gauging Vis a tete fraisee -- Configuration de la tete et verification par calibre First edition - 1983-09-15 UDC 621.88.091.6 Ref. No. 1SO 7721-1983 (E) Descriptors : fasteners, screws, countersunk head screws, dimensions. Price based on 3 pages Copyright International Organization for Standardization ted 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 developing International interested in a subject for which a technical committee has been authorized 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 Council. International Standard ISO 7721 was'developed by Technical Committee ISO/TC 2, Fasteners, and was circulated to the member bodies in December 1981. It has: been approved by the member bodies of the following countries: Australia Germany, F.R. New Zealand Austria Hungary Norway Beigium India Poland Canada Ireland Romania China Italy South Africa, Rep. of Czechoslovakia Japan Spain Denmark Korea, Dem. P. Rep. of Sri Lanka Egypt, Arab Rep. of Korea, Rep. of Sweden Finland Mexico Switzerland France Netherlands USA The member body of the following country expressed disapproval of the document on technical grounds : United Kingdom International Organization for Standardization, 1983 ? . Printed in Switzeriand ed without license from IHS Not for Resale ISO 7721-1983 (E) INTERNATIONAL STANDARD Countersunk head screws -- Head configuration and gauging 1Scope and field of application This International Standard specifies the characteristics of head configurations of slotted and recessed countersunk head screws, and recommends a gauging method for the head dimensions laid down in the respective product standards. 2 Head configuration -Fmax. dktheoretical max. dk theoretical min. -XDW dkactual max. dk actual min. k +2° 006 p Table 1 Dimensions in millimetres M3M3.5 M16 M 18M 20 M 1,6 M2M25 M5 M8 M10|M12 M14 metric M4 M6 Thread ST ST ST ST ST ST sT ST ST size, d tapping 一 2,2 2,9 3,5 4,2 4,8 5,5 6,3 9,5 5,5 40 4,4 6,3 8,2 3,6 9,4 10,4 11,5 12,6 17,3 20 24 28 32 max. 36. theoretical 3,3 4,1 5,1 5,9 7,7 8,9 9,8 11,9 16,5 23,1 27 30,8 34,7 9'88 min. 10,9 19,2 dk 3 3,8 4,7 7,3 max. 8,4 9,3 10,3 11,3 15,8 18,3 22 25,5 29 32,5 36 actual 17,8 28,5 8 15,4 21,5 31,9 35,4 min. 2,7 3,5 4,4 5,2 6,9 8,9 9,9 10,9 25 F 0,15 0,15 0,2 0,2 .0,25 0,25 0,3 0,3 0,35 0,4 0,4 0,45 0,5 0,6 0,75 max. 0,65 metric 1,2 1,5 1,65 2,35 2,7 2,7 3,3 4,65 6 7 5 8 9 10 k max. (ref.) 2,35 tapping 1,1 1,7 2,6 2,8 3 3,15 4,65 5,25 - CopyrightInternational Organization for Standardization Noreoductionornetworking pemitedwithout licensefromHS Not for Resale