1、BRITISH STANDARD BSENISO 7721-2:1995 Specification for Countersunk flat head screws Part 2: Penetration depth of cross recesses The European Standard EN ISO7721-2:1994 has the status of a British Standard UDC 621.882.215.6.091.6BSENISO7721-2:1995 This British Standard, having been prepared under the
2、 directionof the Engineering SectorBoard, was published underthe authority of the Standards Board and comes into effect on 15January1995 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference GME/9 Draft for comment 89/70631 DC ISBN 0 580 23629 3 Cooperatin
3、g organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk S
4、tandard Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland National Standards Authority of Ireland Italy Ente Nazionale I
5、taliano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Swit
6、zerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSENISO7721-2:1995 BSI 11-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN ISO 7721-2 3 Natio
7、nal annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back coverBSENISO7721-2:1995 ii BSI 11-1999 National foreword This British Standard has been prepared under the direction of the Engineering Sector Board and is the English lan
8、guage version of EN ISO7721-2:1994 Countersunk flat head screws Part2: Penetration depth of cross recesses, published by the European Committee for Standardization (CEN). It is identical with ISO7721-2:1990, published by the International Organization for Standardization (ISO). EN ISO7721-2:1994 was
9、 produced as a result of international discussions in which the United Kingdom took an active part. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard
10、does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theENISOtitle page, pages2 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendmen
11、ts incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 7721-2 July 1994 UDC 621.882.215.6.091.6 Descriptors: Fasteners, screws, countersunk head screws, cross recessed screws, dimensions English version Counte
12、rsunk flat head screws Part2: Penetration depth of cross recesses (ISO7721-2:1990) Vis mtaux tte fraise Partie2: Profondeur de pntration des empreintes cruciformes (ISO7721-2:1990) Senkschrauben Teil2: Eindringtiefen von Kreuzschlitzen (ISO7721-2:1990) This European Standard was approved by CEN on19
13、94-07-26. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obt
14、ained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Sec
15、retariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committ
16、ee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref. No. EN ISO7721-2:1994 EENISO7721-2:1994 BSI 11-1999 2 Foreword This European Standard has been taken over by the T
17、echnical Committee CEN/TC185, Threaded and non-threaded mechanical fasteners and accessories, from the work of ISO/TC2, Fasteners, of the International Organization for Standardization (ISO) This European Standard shall be given the status of a national standard, either by publication of an identica
18、l text or by endorsement, at the latest by January1995, and conflicting national standards shall be withdrawn at the latest by January1995. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, Fr
19、ance, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. NOTENormative references to international publications are listed in Annex ZA (normative). Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Dimensions 3
20、 Annex A (informative) Bibliography 5 Annex ZA (normative) Normative references to international publications with their relevant European publications 5 Figure 1 Screw with underhead shoulder 3 Figure 2 Screw without underhead shoulder 3 Table 1 Dimensions 4ENISO7721-2:1994 BSI 11-1999 3 1 Scope Th
21、is part of ISO7721 specifies the penetration depth of cross recesses of countersunk flat head screws for the two series1 and2 (deep and shallow, respectively). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part
22、of ISO7721. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO7721 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IE
23、C and ISO maintain registers of currently valid International Standards. ISO 225:1983, Fasteners Bolts, screws, studs and nuts Symbols and designations of dimensions. ISO 4757:1983, Cross recesses for screws. ISO 7721:1983, Countersunk head screws Head configuration and gauging. 3 Dimensions For app
24、lication of the penetration depths of cross recesses specified in Table 1, different underhead configurations are provided in order to attain sufficient head strength (seeFigure 1 and Figure 2). Both types satisfy the conditions of the common head style as specified in ISO7721 1) NOTE 1Symbols and d
25、esignations of dimensions are specified in ISO225. 1) Will be revised and published under number ISO7721-1 Figure 1 Screw with underhead shoulder Figure 2 Screw without underhead shoulderENISO7721-2:1994 4 BSI 11-1999 Table 1 Dimensions Dimensions in millimetres Recess No. a Cross recesses Series 1
26、(deep) Series 2 (shallow) Thread (d) Type H Type Z Type H Type Z Penetration depth b m Penetration depth b m Penetration depth b m Penetration depth b m Metric Other min. max. ref. min. max. ref. min. max. ref. min. max. ref. M1,6 0 0,6 0,9 1,6 0,70 0,95 1,6 M2 0 0,9 1,2 1,9 0,95 1,20 1,9 0,9 1,2 1,
27、9 0,95 1,20 1,9 ST2,2 0 0,9 1,2 1,9 0,95 1,20 2 M2,5 1 1,4 1,8 2,9 1,48 1,73 2,8 1,25 1,55 2,7 1,22 1,47 2,5 M3 ST2,9 1 1,7 2,1 3,2 1,76 2,01 3 1,4 1,8 2,9 1,48 1,73 2,8 M3,5 ST3,5 2 1,9 2,4 4,4 1,75 2,20 4,1 1,6 2,1 4,1 1,61 2,05 4 M4 ST4,2 2 2,1 2,6 4,6 2,06 2,51 4,4 2,1 2,6 4,6 2,06 2,51 4,4 M5 S
28、T4,8 2 2,7 3,2 5,2 2,60 3,05 4,9 2,3 2,8 4,8 2,27 2,72 4,6 ST5,5 3 2,8 3,3 6,6 2,73 3,18 6,3 M6 ST6,3 3 3,0 3,5 6,8 3,00 3,45 6,6 2,8 3,3 6,6 2,73 3,18 6,3 M8 ST8 4 4,0 4,6 8,9 4,15 4,60 8,8 3,9 4,4 8,7 3,87 4,32 8,5 M10 ST9,5 4 5,1 5,7 10 5,19 5,64 9,8 4,8 5,3 9,6 4,78 5,23 9,4 Application c Screws
29、 without underhead shoulder Screws without underhead shoulder Self-tapping screws Wood screws Screws of property class4.8 Screws with underhead shoulder Screws of property class8.8 Thread forming screws Thread cutting screws entirely heat treated Screws of property classes8.8 and9.8 Thread cutting s
30、crews Thread forming screws a Cross recesses in accordance with ISO4757. b Penetration depth measured in accordance with ISO4757. c Specified for steel screws, application for other materials at manufacturers option. ENISO7721-2:1994 BSI 11-1999 5 Annex A (informative) Bibliography 1 ISO7046:1983, C
31、ross recessed countersunk flat head screws (common head style) Product grade A and property class4.8 only 2) . 2 ISO7046-2:1990, Cross recessed countersunk flat head screws (common head style) Grade A Part2: Steel of property class8.8, stainless steel and non-ferrous metals. Annex ZA (normative) Nor
32、mative references to international publications with their relevant European publications This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed
33、hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). 2) Will
34、be revised and published under number ISO7046-1. IEC publication Year Title EN/HD Year ISO 225 1983 Fasteners Bolts, screws, studs and nuts Symbols and designation of dimensions EN 20225 1991 ISO 4757 1983 Cross recesses for screws EN ISO 4757 1994 ISO 7721 1983 Countersunk head screws Head configur
35、ation and gauging EN 27721 19916 blankBSENISO7721-2:1995 BSI 11-1999 National annex NA (informative) Committees responsible The United Kingdom participation in the preparation of this European Standard was entrusted by the Engineering Sector Board to Technical Committee GME/9, upon which the followi
36、ng bodies were represented: BEAMA Ltd. British Constructional Steelwork Association Ltd. British Industrial Fasteners Federation British Steel Industry British Steel Industry (Wire Section) Gauge and Tool Makers Association National Association of Fastener Stockholders Society of Motor Manufacturers
37、 and Traders Ltd. Washer Manufacturers Association of Great Britain The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Plastics Federation Portable Electric Tool Manufacturers Association Small Electrical Appliances Marketing Associa
38、tion Timber Trade Federation National annex NB (informative) Cross-references Publication referred to Corresponding British Standard ISO 225:1983 BS EN20225:1992 Fasteners Bolts, screws, studs and nuts Symbols and designations of dimensions ISO 4757:1983 BS EN ISO4757:1995 Cross recesses for screws
39、ISO 7721:1983 BS EN 27721:1992 Countersunk head screws Head configuration and gaugingBSENISO 7721-2:1995 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Eu
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