1、BS ISO13921:2008ICS 49.030.20NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDAerospace Screws,100 degrees reducedcountersunk head,internal offsetcruciform ribbedor unribbed drive,normal shank, shortor medium lengthMJ threads, metallicmaterial, coated oruncoated,
2、 strengthclasses less than orequal to 1 100 MPa DimensionsThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31 October2008 BSI 2008ISBN 978 0 580 55027 0Amendments/corrigenda issued since publicationDate CommentsBS ISO 13921:2008National forewordTh
3、is British Standard is the UK implementation of ISO 13921:2008. Itsupersedes BSA311:1997 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee ACE/12, Aerospace fasteners and fastening systems.A list of organizations represented on this committee can be obtai
4、ned onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS ISO 13921:2008Reference numberISO 13921:2008(E)I
5、SO 2008INTERNATIONAL STANDARD ISO13921Second edition2008-08-15Aerospace Screws, 100 degrees reduced countersunk head, internal offsetcruciform ribbed or unribbed drive, normal shank, short or medium length MJ threads, metallic material, coated or uncoated, strength classes less than or equal to 1 10
6、0 MPa Dimensions Aronautique et espace Vis tte fraise 100 degrs rduite, empreinte cruciforme dporte, avec ou sans saillies antidrapantes, tige normale et filetages MJ courts ou de longueur moyenne, en matriau mtallique, revtues ou non revtues, des classes de rsistance infrieures ou gales 1 100 MPa D
7、imensions BS ISO 13921:2008ISO 13921:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer perfo
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10、ecretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in w
11、riting from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reservedBS ISO
12、13921:2008ISO 13921:2008(E) ISO 2008 All rights reserved iiiForeword 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 commit
13、tees. 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, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the In
14、ternational Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International
15、 Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the
16、subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 13921 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 4, Aerospace fastener systems. This second edition cancels and replaces the first edition (
17、ISO 13921:1996), which has been technically revised. BS ISO 13921:2008BS ISO 13921:2008INTERNATIONAL STANDARD ISO 13921:2008(E) ISO 2008 All rights reserved 1Aerospace Screws, 100 degrees reduced countersunk head, internal offset cruciform ribbed or unribbed drive, normal shank, short or medium leng
18、th MJ threads, metallic material, coated or uncoated, strength classes less than or equal to 1 100 MPa Dimensions 1 Scope This International Standard specifies the dimensions of 100 reduced countersunk head screws with internal offset cruciform ribbed or unribbed drive, with close or large tolerance
19、 normal shank and short or medium length MJ threads, in metallic material, coated or uncoated, with strength classes less than or equal to 1 100 MPa. This International Standard is applicable to the compilation of aerospace product standards. 2 Normative references The following referenced documents
20、 are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 286-2, ISO system of limits and fits Part 2: Tables of standard tolerance grade
21、s and limit deviations for holes and shafts ISO 3353-1, Aerospace Lead and runout threads Part 1: Rolled external threads ISO 5855-2, Aerospace MJ threads Part 2: Limit dimensions for bolts and nuts ISO 7913, Aerospace Bolts and screws, metric Tolerances of form and position ISO 14275, Aerospace Dri
22、ves, internal, offset cruciform, ribbed Metric series ISO 14276, Aerospace Drives, internal, offset cruciform Metric series 3 Configuration and dimensions See Figure 1 and Table 1. Dimensions and tolerances are expressed in millimetres. They are applicable after any coating (tolerance on shank diame
23、ter before coating is also specified for heat cured matrix coatings), but before the application of any lubricant. Details of form not stated are left to the manufacturers discretion. Tolerances of form and position shall be as specified in ISO 7913 if not otherwise stated on product standard. BS IS
24、O 13921:2008ISO 13921:2008(E) 2 ISO 2008 All rights reservedDimensions in millimetres Break sharp edges 0,1 to 0,4 Key 1 thread aBlended convex form permitted. bIn accordance with ISO 3353-1. Figure 1 BS ISO 13921:2008ISO 13921:2008(E) ISO 2008 All rights reserved 3Blank page BS ISO 13921:2008ISO 13
25、921:2008(E) 4 ISO 2008 All rights reservedTable 1 D1Coated screws Uncoated screws Tol. Tol. D2D3D4D5D6One hole optionalDiameter code Thread anom. before coatingbclose large close large max. min. nom. Tol. H13 c040 MJ4 0,7-4h6h 4 6,25 5,45 4,82 3 ,0051,1 050 MJ5 0,8-4h6h 5 7,8 6,8 5,79 3,4 060 MJ6 1-
26、4h6h 6 0,030 0,045 0,010 0,035 9,4 8,2 7,71 4,2 1,5 070 MJ7 1-4h6h 7 10,95 9,75 9 5,2 080 MJ8 1-4h6h 8 12,5 11,3 10,28 6,2 1,9 100 MJ10 1,25-4h6h 10 0,033 0,048 0,013 0,038 15,6 14,4 12,86 7,9 120 MJ12 1,25-4h6h 12 18,75 17,55 15,43 9,8 2,4 140 MJ14 1,5-4h6h 14 21,85 20,65 18 11,5 160 MJ16 1,5-4h6h
27、16 25 23,8 20,57 13,5 3 180 MJ18 1,5-4h6h 18 0,036 0,051 0,016 0,041 28,1 26,9 23,14 15,5 200 MJ20 1,5-4h6h 20 0,040 0,055 0,020 0,045 h12 cf7 ch12 c31,2 30 25,71 17,5 0,5 3,8 BS ISO 13921:2008ISO 13921:2008(E) ISO 2008 All rights reserved 5Table 1 (continued) L2L3E F G H L1 0,2 dThread Thread R min
28、. ,0008short medium short medium nom. Tol. Drive codee0,08 0,6 0,4 0,95 3 to 40 7,5 10 5 6 0,4 R3 0,85 0,5 1,18 4 to 50 9 12 6 7,5 0,5 R4 0,71 1,44 5 to 60 10 14 8,5 0,82 1,67 6 to 70 11 15 7 9,5 R5 0,93 1,9 6 to 80 11,5 16,5 7,5 10,5 0,7 R6 1,15 2,37 8 to 100 14,5 20,5 9 13 0,8 ,002R8 1,4 2,86 10 t
29、o 120 16 22,5 10 14,5 0,9 R10 1,62 3,32 10 to 140 19 26 12 17 R12 1,87 3,81 10 to 160 20,5 28,5 12,5 18,5 1,1 R14 2,09 4,28 11 to 180 22,5 31 14,5 21 0,1 2,32 0,6 4,74 12 to 200 24,5 33,5 15 22,5 1,3 ,003R16 aIn conformity with ISO 5855-2, except for the maximum thread major diameter, dmax, of bolts
30、 with a close tolerance on D1, which shall be equal to (D1,min 0,025). bHeat cured organic matrix coatings for close tolerance normal shanks. cSee ISO 286-2. dIncrements: 1 for L1u 30; 2 for 30 100. If greater lengths are required, they shall be chosen using these increments. eIn accordance with ISO
31、 14275 or ISO 14276. BS ISO 13921:2008ISO 13921:2008(E) ICS 49.030.20 Price based on 4 pages ISO 2008 All rights reserved BS ISO 13921:2008This page has been intentionally left blank BS ISO13921:2008BSI GroupHeadquarters 389Chiswick High Road,London, W4 4AL, UKTel +44 (0)20 8996 9001Fax +44 (0)20 89
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