BRITISH STANDARD AEROSPACE SERIES BS A 311 1997 ISO 13921 1996 Aerospace — Screws, 100° reduced countersunk head, internal offset cruciform ribbed or unribbed drive, normal shank, short or medium leng[.]
Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BRITIS H S TAND ARD AE RO S PAC E S E RIE S BS A 1 : 997 IS O 92 : 996 Aerospace — Screws, 0 ° reduced countersunk head, internal offset cruciform rib b ed or unrib b ed drive, normal shank, short or medium length MJ threads, metallic material, coated or uncoated, strength classes less than or equal to 1 0 MPa — D imensions IC S 49 Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS A 311:1997 Committees responsible for this British Standard The p rep aration of this Britis h S tandard was entrusted b y Technical C ommittee AC E /1 , Aerosp ace fas teners and fas tening s ystems , up on which the following b odies were rep res ented: British Indus trial Fasteners Federation Minis try of D efence S ociety of Britis h Aerosp ace C omp anies This Britis h S tandard, having b een p rep ared under the direction of the E ngineering S ector Board, was p ub lis hed under the authority of the S tandards Board and comes into effect on Amendments issued since publication March 97 Amd No © BS I 1 - 9 The following BS I references relate to the work on this s tandard: C om mittee reference AC E /1 D raft for comment 4/71 D C ISBN 580 26628 D ate C omments Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS A 311:1997 Contents Page Committees responsib le National foreword ii Scope Normative references C onfiguration and dimensions Figure 1 Table List of references © BSI 1 - 998 Inside front cover Inside back cover i Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS A 31 :1 997 National foreword This British Standard has been prepared by Technical Committee ACE/1 It is identical with ISO 3921 : 996, head, Aero sp ace — Screw s, 00° reduced countersunk internal o ffset cruciform rib b ed or unrib b ed driv e, m edium length MJ threads, m etallic m aterial, classes les s than or eq ual to norm al shank, coated or uncoated, 00 MPa — Dim ensio ns short or s trength , published by the International Organization for Standardization (ISO) Cross-references International standard ISO 3353: 992 C orresponding British Standard BS 2A 231 : 993 Rolled threads for b olts Lead and runout req uirem ents (Identical) ISO 5855- 2: 988 BS 6293 Aero sp ace Part 2: 994 MJ threads Lim it dim ensions for b olts and nuts (Identical) ISO 791 3: 994 BS 2A 296: 995 Bolts and screw s, m etric Tolerances of fo rm and p os ition (Identical) 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 does not of itself confer immunity from legal obligations Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages and 2, an inside back cover and a back cover This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover ii © BSI 1 - 998 Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS A 311:1997 Scope ISO 86- : 988, ISO system of lim its and fits — Part 2: Tab les of s tandard tolerance grades and This International Standard specifies the lim it dev iations for holes and shafts dimensions of 00° reduced countersunk head ISO 3353: 992 , screws with internal offset cruciform rib bed or Aero sp ace — Rolled threads for unribb ed drive, close or large tolerance normal b olts — Lead and runout req uirem ents shank, short or medium length MJ threads, in ISO 5855- : 988, metallic material, coated or uncoated, with strength Part 2: Lim it dim ensions fo r b olts and nuts classes less than or equal to 1 00 MPa ISO 791 3: 994, This International Standard is applicab le to the Aeros p ace — MJ threads — Aeros p ace — Bolts and screw s, m etric — Tolerances o f fo rm and p o sitio n compilation of aerospace product standards ISO 42 75: — cruciform , Normative references 1) 1) ISO 42 76: — The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard At the time of publication, the editions indicated were valid All standards are subj ect to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated b elow Memb ers of IEC and ISO maintain registers of currently valid International Standards , Aerosp ace — Drives , internal, offset rib b ed — Metric series , Aerosp ace — Drives , internal, offset cruciform — Metric series Configuration and dimensions See Figure and Tab le D imensions and tolerances are expressed in millimetres They are applicable after any surface coating, but before the application of any lubricant D etails of form not stated are left to the manufacturer’s discretion Tolerances of form and position are specified in ISO 791 Figure 1) To b e published © BSI 1 - 998 Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI BS A 1 : 997 Tab le D D C o ate d scre ws D iame te r Thre ad co d e D D H L c Unco ate d ab scre ws no m to l clo se 040 MJ4 × 0, – 4h6h 050 MJ5 × 0, – 4h6h to l large clo se large max mi n 6, 5 , 45 4, 82 0, 95 to 40 7, 6, , 79 1,18 to ± 0, – 0, 01 – 0, 03 60 MJ6 × – 4h6h 9, 70 MJ7 × – 4h6h , 95 80 MJ8 × – 4h6h – 0, 01 00 MJ1 × , – 4h6h – 0, 03 20 MJ1 × , – 4h6h 40 MJ1 × , – 4h6h 14 – 0, 01 60 MJ1 × , – 4h6h 16 – 0, 041 80 MJ1 × , – 4h6h 18 200 MJ2 × , – 4h6h 20 h1 d f7 d h1 d 8, , 71 , 44 to 60 , 75 , 67 to 2, 11,3 0, 1,9 to 80 5, 4, , 86 , 37 to 0 8, 75 7, 5 , 43 , 86 to 2 , 85 0, 65 18 3, 32 to 40 25 23, 20, 57 , 81 to 60 8, 6, 23, 4, 1 to 80 31 , 30 25, 71 4, 74 to 0 – 0, 02 – 0, 045 Tab le L D i ame te r L Thre ad D F R E D Y Thre ad D ri ve co d e co d e sho rt me d i u m sho rt me d iu m no m to l no m – 0, 08 to l H1 e d 040 7, 10 0, 0, , 85 0, 0, 08 1,1 0, R3 0, R4 – 0, 05 12 7, 3, 1,5 060 10 14 070 11 15 8, 4, , 71 9, 5, , 82 R5 0, – 0, 1,9 80 11,5 6, 7, 0, 6, 00 4, 0, 13 7, 120 16 22, 10 4, 9, 40 19 26 12 17 , 93 ± 0, R6 1,15 0, 1,4 0, 0, R8 2,4 R1 0, 11,5 , 62 60 0, 8, 2, 8, 3, , 87 80 22, 31 4, 21 5, , 09 200 4, 33, 15 22, 7, , 32 a c In accordance with IS O 85 - d D For coated or uncoated s crews with a clos e tolerance on max = L L for for e D , the thread maj or diameter, 3, d R1 , s hall b e – 0, 02 I ncrements : ≤ for < d R1 – 0, 1,3 b R1 1,1 L 30 ≤ 00 > 00 I f greater lengths are required, they s hall b e chos en us ing thes e increments S ee I S O 86 - I n accordance with IS O 42 75 or I S O 42 76 © BS I 1 - 99 Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI (see clause List of references Normative references © BSI 1 - 998 2) BS A 311:1997 Li cen sed Copy: Lon d on Sou th Ban k U n i versi ty, Lon d on Sou th Ban k U n i versi ty, Sat Dec 09 03: 32: 42 G M T+00: 00 2006, U n trol l ed Copy, (c) BSI | | | | | | | | | BSI Ð British Standards Institution | | | | | | | BSI is the independent national body responsible for preparing British Standards It | | | | | | | presents the UK view on standards in E urope and at the international level It is incorporated by Royal Charter Revisions | | | | British Standards are updated by amendment or revision Users of British Standards should make sure that they possess the latest amendments or editions | | | It is the constant aim of BSI to improve the quality of our products and services We | | | | | | | | would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover Tel: 02 8996 9000 Fax: 02 8996 7400 | | BSI offers members an individual updating service called PLUS which ensures that | | | | | | | | | | subscribers automatically receive the latest editions of standards Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services Tel: 02 8996 9001 Fax: 02 8996 7001 | | | | In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless | | | | | | otherwise requested Information on standards | | | | | | | | | BSI provides a wide range of information on national, E urop ean and international standards through its Library and its Technical Help to E xporters Service Various BSI electronic information services are also available which give details on all its products and services Contact the Information C entre Tel: 02 8996 71 1 Fax: 02 8996 7048 | | | Subscribing members of BSI are kept up to date with standards developments and | | | | | | | | | receive substantial discounts on the purchase price of standards For details of these and other benefits contact Membership Administration Tel: 020 8996 7002 Fax: 02 8996 7001 Copyright | | Copyright subsists in all BSI publications BSI also holds the copyright, in the UK, of | | the publications of the international standardization bodies E xcept as permitted | | | | | | under the C opyright, D esigns and Patents Act 988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means ± electronic, photocop ying, recording or otherwise ± without p rior written permission from BSI | | | | This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations If these | | details are to be used for any other purpose than implementation then the prior | | written permission of BSI must be obtained | | | | | | | | | | | | | | | BSI | | 389 C hiswick High Road | | London | | W4 4AL | | | | | | | If permission is granted, the terms may include royalty payments or a licensing agreement Details and advice can be obtained from the Copyright Manager Tel: 02 8996 7070