1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ICS 21.060.10 ISBN 0-626-15631-9 SANS 1700-3-12:1996 Edition 1 and nat. amdt 1 ISO 7721-2:1990 Edition 1 Any reference to SABS 1700-3-12 is deemed to be
4、a reference to this standard (Government Notice No. 1373 of 8 November 2002) SOUTH AFRICAN NATIONAL STANDARD Fasteners Part 3: Forms, dimensions and designations Section 12: Countersunk flat head screws Penetration depth of cross recesses This national standard is the identical implementation of ISO
5、 7721-2:1990 and is adopted with the permission of the International Organization for Standardization. Published by Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Afric
6、a SANS 1700-3-12:1996 Edition 1 and nat. amdt 1 ISO 7721-2:1990 Edition 1 Table of changes Change No. Date Scope Nat. amdt 1 2004 Amended to change the designation of SABS standards to SANS standards with no technical changes. Abstract Specifies the penetration depth of cross recesses of countersunk
7、 flat head screws for the 2 series 1 and 2 (deep and shallow, respectively). Keywords countersunk fasteners, depth measurement, designations, dimensions, fasteners, patterns (product engineering), recesses, screws (bolts), specifications. National foreword This South African standard was approved by
8、 National Committee StanSA TC 5120.01, Screw threads and fasteners, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This edition is technically identical to SABS 1700-3-12:1996. INTERNATIONAL STANDARD 77212 First edition 1990-09-o 1 Count
9、ersunk flat head screws - Part 2: Penetration depth of cross recesses l/is ZI m this can only be achieved by a sufficiently deep cross recess. IS0 7721-2 was developed in order to find a compromise which, as far as possible, would meet both requirements. This part of IS0 7721 specifies deep cross re
10、cesses for countersunk head screws of low strength: a good wrenchability is achieved and the head strength is still sufficient. This execution will be used in IS0 7046-I (see annex A). For screws of higher strength, sufficient head strength can only be at- tained by a shallower penetration depth of
11、the cross recesses. If such screws also require good wrenchability, then, under the conditions of the common head style, a shoulder has to be provided under the head, in addition to the larger penetration depth, in order to guarantee suffi- cient head strength. This compromise, which unfortunately r
12、esults in different but inter- changeable types of cross recessed flat countersunk head screws, is at the moment the only way of reaching an agreement at the international level. . . . Ill This page intentionally left blank INTERNATIONAL STANDARD IS0 772%2:1990(E) Countersunk flat head screws - Part
13、 2: Penetration depth of cross recesses 1 Scope This part of IS0 7721 specifies the penetration depth of cross recesses of countersunk flat head screws for the two series 1 and 2 (deep and shallow, re- spectively). 2 Normative references The following standards contain provisions which, through refe
14、rence in this text, constitute provisions of this part of IS0 7721. 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 IS0 7721 are encouraged to investi- gate the possibility of applying the most rece
15、nt edi- tions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 225:1983, Fasteners - Bolts, screws, studs and nuts - Symbols and designations of dimensions. IS0 4757:1983, Cross recesses for screws. IS0 7721:1983, Countersunk
16、 head screws - Head configuration and gauging. 3 Dimensions For application of the penetration depths of cross recesses specified in table 1, different underhead configurations are provided in order to attain suffi- cient head strength (see figure 1 and figure 2). Both types satisfy the conditions o
17、f the common head style as specified in IS0 7721l). NOTE 1 Symbols and designations of dimensions are specified in IS0 225. IP n _- b I L-h-L- a max = 2S P Figure 1 - Screw with underhead shoulder 7 b 1 a max = 2P Figure 2 - Screw without underhead shoulder 1) Will be revised and published under num
18、ber IS0 7721-1 IS0 772+2:1990(E) Table I - Dimensions Dimensions in milllmetres ST2,2 0 o,g 192 179 0,95 A,20 2 - -.- - - _ - - M2,5 - 1 194 138 299 I,48 I,73 2,8 I,25 I,55 2,? I,22 I,47 2,5 - M3 ST2,9 1 157 291 372 I,?6 2,Ol 3 134 118 279 I,48 I,?3 2,8 N3,5 ST3,5 2 199 2,4 4,4 I,?5 2,20 4,l I,6 291
19、 411 I,61 2,05 4 M4 ST4,2 2 291 2,6 4,6 2,06 2,51 4,4 2,l 2,6 4,6 2,06 2,51 4,4 M5 ST4,8 2 2,? 3,2 5,2 2,60 3,05 4,9 2,3 2,8 4,8 2,2? 2,?2 4,6 3 2,8 3,3 6,6 2,?3 3,18 6,3 _- -_ _ ST5,5 - - - - M6 A118 Ml0 ST6,3 ST8 ST9,5 Application 3, 3,0 3,5 6,8 3,00 3,45 6,6 2,8 3,3 6,6 2,?3 3,18 6,3 4,O 496 839
20、4,15 4,60 8,8 3,9 494 897 3,8? 4,32 8,5 - 591 5,? IO 5,19 5,64 9,8 4,8 5,3 9,6 4,?8 5,23 9,4. Screws without underhead shoulder Screws without underhead shoulder Self-tapping screws Wood screws Screws of property Screws of property class 4.8 class 8.8 entirely heat treated Thread forming screws Scre
21、ws with under-head shoulder Thread cutting screws Screws of property classes 8.8 and 9.8 Thread cutting screws Thread forming screws I) Cross recesses in accordance with IS0 4757. 2) Penetration depth measured in accordance with IS0 4757. 3) Specified for steel screws, application for other material
22、s at manufacturers option. 2 IS0 7721=2:1990(E) Annex A (informative) Bibliography I IS0 7046:1983, Cross recessed countersunk flat head screws (common head style) - Product grade A and property class 4.8 only.*1 2 IS0 7046-2:1990, Cross recessed countersunk f7at head screws (common head style) - Grade A - Part 2: Steel of property class 8.8, stainless steel and non-ferrous metals. 2) Will be revised and published under nurnber IS0 7046-l.
