BRITISH STANDARD AEROSPACE SERIES BS A 312 1997 ISO 12260 1996 Aerospace — Screws, pan head, internal offset cruciform ribbed or unribbed drive, stepped shank, short or medium length MJ threads, metal[.]
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 : 997 IS O 2 60 : 996 Aerospace — Screws, pan head, internal offset cruciform rib b ed or unribb ed drive, step ped 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 312:1997 Committees responsible for this British Standard The p rep aration of this Britis h S tandard was entrus ted to 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 - 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 26647 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 312:1997 Contents Page Committees responsib le National foreword ii Scope Normative references C onfiguration and dimensions Figure 1 Table List of references © BSI 01 - 999 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 2:1 997 National foreword This British Standard has been prepared by Technical Committee ACE/1 It is identical with ISO 2260: 996, Aero sp ace — Screw s , crucifo rm rib b ed o r unrib b ed driv e, thread, to m etallic m aterial, step p ed shank, coated or unco ated, 00 MPa — Dim ensions, p an head, internal o ffset s hort o r m edium length MJ strength classes les s than or eq ual published by the International Organization for Standardization (ISO) Cross-references Publication referred to Corresponding British Standard ISO 286- 2: 988 BS EN 20286- 2: 993 ISO system o f lim its and fits Tab les of standard tolerance grades and lim it dev iatio ns for ho les and shafts (Identical) ISO 3353: 992 BS 2A 231 : 993 Rolled threads for b olts Lead and runout req uirem ents (Identical) ISO 5855- 2: 988 BS 6293 Aeros p ace Part 2: 994 MJ threads Lim it dim ensio ns for b olts and nuts (Identical) ISO 791 3: 994 BS 2A 296: 995 Bo lts and screw s, m etric To lerances of fo rm and p o sition (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 01 - 999 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 312:1997 Scope ISO 86- : 988, ISO s ystem of lim its and fits — Part 2: Tab les o f standard tolerance grades and This International Standard specifies the lim it dev iations for holes and shafts dimensions of pan head screws with internal offset cruciform ribb ed or unrib bed drive, stepped shank, ISO 3353: 992 , Aero sp ace — Rolled threads for short or medium length MJ threads, in metallic b olts — Lead and runout req uirem ents material, coated or uncoated, with strength classes ISO 5855- : 988, less than or equal to 1 00 MPa Part 2: Lim it dim ensio ns for b olts and nuts Aeros p ace — MJ threads — This International Standard is applicab le to the ISO 791 3: 994, compilation of aerospace product standards m etric — Tolerances o f fo rm and p o sitio n 1) , Aeros p ace — Bolts and screw s, Normative references ISO 42 75: — The following standards contain provisions which, ISO 42 76: — through reference in this text, constitute provisions cruciform — Metric series cruciform , 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 1) , Aerosp ace — Drives , internal, offset Configuration and dimensions See Figure and Tab le D imensions and tolerances are expressed in millimeters They are applicable after any surface coating, but before the application of any lubricant Tolerances of form and position are specified in ISO 791 Figure 1) To b e published © BSI 01 - 999 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 : 997 Tab le D iameter cod e Thread a D1 h1 40 MJ4×0,7 – 4h6h b D2 D3 –03 6,7 , D4 nom D5 tol h1 –0 , b + 0,2 K L1 c L2 nom 0,4 2,4 ± ,2 short to 40 7,5 – to 50 10 0,4 12 0,5 3,9 8,7 10 3,4 4,6 10,7 12 4,2 3,6 to 60 10 14 70 MJ7×1 – 4h6h 5,6 12,7 14 5,2 0,7 4,2 to 70 11 15 80 MJ8×1 – 4h6h 6,6 14,7 16 6,2 MJ10×1,25 – 4h6h 8,3 18,7 20 7,9 9,8 12 , 0,7 –0 to 80 11,5 16,5 0,8 to 100 14,5 20,5 0,8 0,9 7,2 to 120 16 22,5 0,9 4,8 , d D rive nom MJ5×0,8 – 4h6h MJ12×1,25 – 4h6h 10,3 22,7 24 T code medium MJ6×1 – h6h 00 0, tol 050 ± 0,5 10 R Thread 60 20 E tol max 1,6 0,4 R4 0,5 R5 2,4 0,6 – 2,8 0,7 3,2 0,8 R8 R10 1,2 R12 , – 4,8 , R6 a In accordance with ISO 5855-2 b See ISO 286-2 c Increments: for L1 < 30 for 30 < L < 100 for L1 > 100 d In accordance with ISO 14275 or ISO 14276 © BSI 01-1999 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 List of references See national foreword © BSI 01 - 999 BS A 312:1997 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