untitled BSI Standards Publication BS 2A 266 to 2A 271 2016 AEROSPACE SERIES Bolt, 100° Countersunk head, Hi Torque speed drive recess, UNJF thread, split pin hole option, titanium alloy, various fini[.]
BS 2A 266 to 2A 271:2016 BSI Standards Publication AEROSPACE SERIES Bolt, 100° Countersunk head, Hi-Torque speed drive recess, UNJF thread, split pin hole option, titanium alloy, various finishes, Classification: 80 Tf/in2 (1 100 MPa) at TA/+315 °C BS 2A 266 to 2A 271:2016 BRITISH STANDARD Publishing and copyright information The BSI copyright notice displayed in this document indicates when the document was last issued © The British Standards Institution 2016 Published by BSI Standards Limited 2016 ISBN 978 580 91579 ICS 49.030.20 The following BSI references relate to the work on this document: Committee reference ACE/12 Draft for comment 15/30329889 DC Publication history First published January 1977 Second (current) edition February 2016 Amendments issued since publication Date Text affected BRITISH STANDARD BS 2A 266 to 2A 271:2016 Contents Foreword ii Scope Normative references General requirements BS part number 12 Indentification and marking Bibliography List of Figure Figure Figure Figure 12 13 figures – Basic dimensions 2 – Dimensions: length and optional hole position variables – Example of part number call up 12 – Typical dispersion of the various markings 12 List of tables Table – Dimensions (standard shank diameters) Table – Oversize shank diameters Table – Material and protective finish Table – Dimensions: lengths and optional hole position variables Summary of pages This document comprises a front cover, an inside front cover, pages i to ii, pages to 14, an inside back cover and a back cover â The British Standards Institution 2016 ã i BS 2A 266 to 2A 271:2016 BRITISH STANDARD Foreword Publishing information This British Standard is published by BSI Standards Limited, under licence from The British Standards Institution, and came into effect on 29 February 2016 It was prepared by Technical Committee ACE/12, Aerospace fasteners and fastening A list of organizations represented on this committee can be obtained on request to its secretary Supersession This British Standard supersedes BS A 266 to A 271:1977, which is withdrawn Information about this document This British Standard has been prepared to provide a range of 80 Tf/in2 (1 100 MPa) to 90 Tf/in2 (1 250 MPa) titanium alloy bolts with UNJF profile threads and close tolerance shanks for aerospace use The lengths of the bolts are in fractional increments Dimensions for oversize shank diameters are also included When considering the use of cadmium plated titanium bolts, attention is drawn to Def Stan 00-970 Pt.1/12 Section Leaflet 8, which recommends certain limitations on their use When bolts are drilled for split pins, they are suitable for use with hexagonal castle nuts specified in BS A 242 to 245 This is a full revision of the standard, and introduces the following principal changes: • updating and/or providing additional alternative reference document numbers; • adding alternative materials to the existing BS TA 28; • adding reference document numbers for flushness control and the drive recess; and • specifying a temperature rating relating to the strength class Presentational conventions The provisions of this standard are presented in roman (i.e upright) type Its requirements are expressed in sentences in which the principal auxiliary verb is “shall” Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element Contractual and legal considerations This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application Compliance with a British Standard cannot confer immunity from legal obligations ii ã â The British Standards Institution 2016 BRITISH STANDARD BS 2A 266 to 2A 271:2016 Scope This British Standard specifies the materials, dimensions, finish and inspection requirements for titanium alloy bolts with 100° countersunk heads and UNJF threads for aerospace use NOTE The values in Imperial British units are to be regarded as the standard CAUTION A269 has cadmium as a plating material, which has been restricted and/or banned for use in many countries owing to environmental and health concerns; they should not be used in new product designs Local officials should be consulted about any concerns on using cadmium-plated parts Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies AMS 4967, Titanium alloy, bars, wire, forgings and rings, 6.0Al – 4.0V, annealed, heat treatable BS A 346 (ISO 3161), UNJ threads – General requirements and limit dimensions BS A 101, Specification for general requirements for titanium bolts BS A 242 to 245, Specification for hexagonal castle nuts (of class 3B UNJ thread) BS A 272, Specification for Hi-torque speed drive recesses – Dimensions and gauging for countersunk head fasteners BS A 273, Specification for gauging practice for 100° countersunk head fasteners for flushness control BS EN 2133, Cadmium plating of steels with specified tensile strength ≤ 1450 MPa, copper, copper alloys and nickel alloys BS EN 2808, Anodizing of titanium and titanium alloys BS EN 3813, Titanium alloy TI-P64001 (Ti-6AI-4V) – Annealed – Bar and wire for forged fasteners – De ≤ 50 mm BS M 58 (ISO 8080), Specification for anodic coating of titanium and titanium alloys by the sulphuric acid process BS TA 28, Specification for forging stock and wire of titanium–aluminium–vanadium alloy (tensile strength 1100–1300 MPa) (limiting ruling section 20 mm) DTD 942, Anodizing of titanium and titanium alloys SAE AMS 03-19, Electro-deposition of cadmium SAE AS5272, Lubricant, solid film, heat cured, corrosion inhibiting procurement specification SAE ITC RS678, Fasteners, rolled threads, chamfers, lead threads and runouts â The British Standards Institution 2016 ã BS 2A 266 to 2A 271:2016 BRITISH STANDARD General requirements 3.1 The bolts shall be manufactured, inspected and tested in accordance with the requirements of BS A 101 3.2 All bolts shall conform to the dimensions and tolerances given in Table 1, Table 2, Table and Figure Unless otherwise specified, the dimensions are those before the application of the protective finish 3.3 The principles of flushness control and recommended gauging practice shall be in accordance with BS A 273 3.4 The dimensions of the Hi-torque speed drive recesses shall be as specified in BS A 272 3.5 The material and protective finish requirements shall be as specified in Table Figure Basic dimensions a) Dimensions of bolt b) Enlarged view of head Notes 1) The thread lead and runout shall conform to the requirements of SAE ITC RS678 2) See Figure and Table for length dimensions “E”, “L” and “M” 3) The split pin hole option was originally designed to suit the hexagonal castle nuts specified in BS A 242 to 245 4) Holes shall have the sharp edges removed 5) For flushness control and gauging of head and drive recess, see BS A 272 and BS A 273 ã â The British Standards Institution 2016 03 04 05 06 07 08 Dia code Table 190 250 3125 375 4375 500 Nom UNJF 10–32 1/4–28 5/16–24 3/8–24 7/16–20 1/2–20 Shank dia Thread size A) 1895 2495 312 3745 437 4995 A 268 B) Max A 267 A 266 øA Type: Dimensions (standard shank diameters) 189 249 3115 374 4365 499 Min (1 of 2) 1895 2495 312 3745 437 4995 Max A 269 C) øA Type: 1885 2485 311 3735 436 4985 Min 063 071 083 083 100 100 381 443 506 615 631 757 Min Ref Thread lead & runout Max T × Pitch 385 507 635 762 890 1.017 Max 10 øV 376 497 625 752 880 1.007 Min 11 Dimensions in inches BRITISH STANDARD BS 2A 266 to 2A 271:2016 â The British Standards Institution 2016 ã • © The British Standards Institution 2016 D) C) B) A) 03 04 05 06 07 08 080 106 133 160 188 215 Ref Absolute minimum 328 449 577 704 832 959 14 D D) 13 øB 3147 4245 5389 6532 7676 882 Basic Gauging diameter 15 øN (2 of 2) 029 0342 0395 045 0503 0557 Max 0263 0316 037 0426 0481 0537 Min 16 17 Head protrusion Protrusion above gauging diameter P Dimensions (standard shank diameters) 0027 0026 0025 0024 0022 002 Flushness tolerance 18 025 025 025 025 025 025 Max 19 R 015 015 015 015 020 020 Min 20 130 184 239 302 354 416 ±.020 Cham 21 øG 073 083 104 125 146 167 22 øJ hole +.007 +.0055 tol 23 24 Driver and recess number The screw threads shall conform to the basic thread form, diameter and related pitches specified in BS A 346 for class 3A Before application of protective finish After application of protective finish Applies to standard bolt shank diameter only Head height dimensions are reduced with oversize shanks Reduction is: 0065 in for 05156 in oversize bolts and 013 in for 0312 in oversize bolts 12 Dia code Table BS 2A 266 to 2A 271:2016 BRITISH STANDARD BRITISH STANDARD Table BS 2A 266 to 2A 271:2016 Oversize shank diameters Dimensions in inches Dia code Thread size First oversize (code X) øA øA Type: Type: Second oversize (code Y) øA øA Type: Type: A 269 B) A 266 03 04 05 06 07 08 A) B) UNJF A 268 Max 10–32 1/4–28 5/16–24 3/8–24 7/16–20 1/2–20 2026 2651 3276 3901 4526 5151 A 269 B) A 266 A 267 10 A 267 A) Min Max Min A 268 A) Max 2021 2646 3271 3896 4521 5146 2026 2651 3276 3901 4526 5151 2016 2641 3266 3891 4516 5141 2182 2807 3432 4057 4682 5307 Min Max Min 2177 2802 3427 4052 4677 5302 2182 2807 3432 4057 4682 5307 2172 2797 3422 4047 4672 5297 Before application of protective finish After application of protective finish Table Material and protective finish Basic BS number Material Mechanical properties Protective finish A266 A267 Titanium alloy Ti-6Al-4V to BS TA 28 or BS EN 3813 or AMS 4967 0.2% proof stress: not less than 70 Tf/in2 (970 MPa) None Anodized in accordance with DTD 942 or BS EN 2808 or BS M 58 (ISO 8080) Anodized in accordance with DTD 942 or BS EN 2808 or BS M 58 (ISO 8080) + MoS2 dry film lube (heat cured) in accordance with SAE AS5272, Type (Joint Services Designation ZX-34, NATO S-1738) Cadmium plated in accordance with SAE AMS 03-19 or BS EN 2133 on nickel strike Not yet allocated Not yet allocated A268 Tensile strength: not less than 80 Tf/in2 (1 100 MPa) and not more than 90 Tf/in2 (1 250 MPa) A269 A) A270 A271 A) Elongation on 5.65 not less than 8% ŒSo Inactive for new design Figure Dimensions: length and optional hole position variables Unallocated diameter/length codes shall not be used â The British Standards Institution 2016 ã 0302 0303 0304 0305 0306 0307 0308 0309 0310 0311 0312 0313 0314 0315 0316 0317 0318 0319 0320 0321 0322 0323 0324 0325 0326 0327 0328 0329 0330 Dia/length code Table 125 188 250 312 375 438 500 562 625 688 750 812 875 938 1.000 1.062 1.125 1.188 1.250 1.312 1.375 1.438 1.500 1.562 1.625 1.688 1.750 1.812 1.875 531 594 656 718 781 844 906 968 1.031 1.094 1.156 1.218 1.281 1.344 1.406 1.468 1.531 1.594 1.656 1.718 1.781 1.844 1.906 1.968 2.031 2.094 2.156 2.218 2.281 10–32 UNJF L ±.010 E ±.015 396 459 521 583 646 709 771 833 896 959 1.021 1.083 1.146 1.209 1.271 1.333 1.396 1.459 1.521 1.583 1.646 1.709 1.771 1.833 1.896 1.959 2.021 2.083 2.146 M ±.010 – 0403 0404 0405 0406 0407 0408 0409 0410 0411 0412 0413 0414 0415 0416 0417 0418 0419 0420 0421 0422 0423 0424 0425 0426 0427 0428 0429 0430 Dia/length code (1 of 6) – 656 718 780 843 906 968 1.030 1.093 1.156 1.218 1.280 1.343 1.406 1.468 1.530 1.593 1.656 1.718 1.780 1.843 1.906 1.968 2.030 2.093 2.156 2.218 2.280 2.343 – 188 250 312 375 438 500 562 625 688 750 812 875 938 1.000 1.062 1.125 1.188 1.250 1.312 1.375 1.438 1.500 1.562 1.625 1.688 1.750 1.812 1.875 1/4–28 UNJF L ±.010 E ±.015 Dimensions: lengths and optional hole position variables – 491 553 615 678 741 803 865 928 991 1.053 1.115 1.178 1.241 1.303 1.365 1.428 1.491 1.553 1.615 1.678 1.741 1.803 1.865 1.928 1.991 2.053 2.115 2.178 M ±.010 – 0503 0504 0505 0506 0507 0508 0509 0510 0511 0512 0513 0514 0515 0516 0517 0518 0519 0520 0521 0522 0523 0524 0525 0526 0527 0528 0529 0530 Dia/length code – 188 250 312 375 438 500 562 625 688 750 812 875 938 1.000 1.062 1.125 1.188 1.250 1.312 1.375 1.438 1.500 1.562 1.625 1.688 1.750 1.812 1.875 – 719 781 843 906 969 1.031 1.093 1.156 1.219 1.281 1.343 1.406 1.469 1.531 1.593 1.656 1.719 1.781 1.843 1.906 1.969 2.031 2.093 2.156 2.219 2.281 2.343 2.406 – 549 611 673 736 799 861 923 986 1.049 1.111 1.173 1.236 1.299 1.361 1.423 1.486 1.549 1.611 1.673 1.736 1.799 1.861 1.923 1.986 2.049 2.111 2.173 2.236 Dimensions in inches 5/16–24 UNJF L ±.010 E ±.015 M ±.010 BS 2A 266 to 2A 271:2016 • © The British Standards Institution 2016 BRITISH STANDARD 0331 0332 0334 0336 0338 0340 0342 0344 0346 0348 0350 0352 0354 0356 0358 0360 0362 0364 0366 0368 0370 0372 0374 0376 0378 0380 0382 0384 0386 Dia/length code Table 1.938 2.000 2.125 2.250 2.375 2.500 2.625 2.750 2.875 3.000 3.125 3.250 3.375 3.500 3.625 3.750 3.875 4.000 4.125 4.250 4.375 4.500 4.625 4.750 4.875 5.000 5.125 5.250 5.375 2.344 2.406 2.531 2.656 2.781 2.906 3.031 3.156 3.281 3.406 3.531 3.656 3.781 3.906 4.031 4.156 4.281 4.406 4.531 4.656 4.781 4.906 5.031 5.156 5.281 5.406 5.531 5.656 5.781 10–32 UNJF L ±.010 E ±.015 2.209 2.271 2.396 2.521 2.646 2.771 2.896 3.021 3.146 3.271 3.396 3.521 3.646 3.771 3.896 4.021 4.146 4.271 4.396 4.521 4.646 4.771 4.896 5.021 5.146 5.271 5.396 5.521 5.646 M ±.010 0431 0432 0434 0436 0438 0440 0442 0444 0446 0448 0450 0452 0454 0456 0458 0460 0462 0464 0466 0468 0470 0472 0474 0476 0478 0480 0482 0484 0486 Dia/length code (2 of 6) 1.938 2.000 2.125 2.250 2.375 2.500 2.625 2.750 2.875 3.000 3.125 3.250 3.375 3.500 3.625 3.750 3.875 4.000 4.125 4.250 4.375 4.500 4.625 4.750 4.875 5.000 5.125 5.250 5.375 2.406 2.468 2.593 2.718 2.843 2.968 3.093 3.218 3.343 3.468 3.593 3.718 3.843 3.968 4.093 4.218 4.343 4.468 4.593 4.718 4.843 4.968 5.093 5.218 5.343 5.468 5.593 5.718 5.843 1/4–28 UNJF L ±.010 E ±.015 Dimensions: lengths and optional hole position variables 2.241 2.303 2.428 2.553 2.678 2.803 2.928 3.053 3.178 3.303 3.428 3.553 3.678 3.803 3.928 4.053 4.178 4.303 4.428 4.553 4.678 4.803 4.928 5.053 5.178 5.303 5.428 5.553 5.678 M ±.010 0531 0532 0534 0536 0538 0540 0542 0544 0546 0548 0550 0552 0554 0556 0558 0560 0562 0564 0566 0568 0570 0572 0574 0576 0578 0580 0582 0584 0586 Dia/length code 1.938 2.000 2.125 2.250 2.375 2.500 2.625 2.750 2.875 3.000 3.215 3.250 3.375 3.500 3.625 3.750 3.875 4.000 4.125 4.250 4.375 4.500 4.625 4.750 4.875 5.000 5.125 5.250 5.375 2.469 2.531 2.656 2.781 2.906 3.031 3.156 3.281 3.406 3.531 3.656 3.781 3.906 4.031 4.156 4.281 4.406 4.531 4.656 4.781 4.906 5.031 5.156 5.281 5.406 5.531 5.656 5.781 5.906 2.299 2.361 2.486 2.611 2.736 2.861 2.986 3.111 3.236 3.361 3.486 3.611 3.736 3.861 3.986 4.111 4.236 4.361 4.486 4.611 4.736 4.861 4.986 5.111 5.236 5.361 5.486 5.611 5.736 Dimensions in inches 5/16–24 UNJF L ±.010 E ±.015 M ±.010 BRITISH STANDARD BS 2A 266 to 2A 271:2016 © The British Standards Institution 2016 • 0388 0390 0392 0394 0396 Dia/length code Table 5.500 5.675 5.750 5.875 6.000 5.906 6.031 6.156 6.281 6.406 10–32 UNJF L ±.010 E ±.015 5.771 5.896 6.021 6.146 6.271 M ±.010 0488 0490 0492 0494 0496 Dia/length code (3 of 6) 5.500 5.625 5.750 5.875 6.000 5.968 6.093 6.218 6.343 6.468 1/4–28 UNJF L ±.010 E ±.015 Dimensions: lengths and optional hole position variables 5.803 5.928 6.053 6.178 6.303 M ±.010 0588 0590 0592 0594 0596 Dia/length code 5.500 5.625 5.750 5.875 6.000 6.031 6.156 6.281 6.406 6.531 5.861 5.986 6.111 6.236 6.361 Dimensions in inches 5/16–24 UNJF L ±.010 E ±.015 M ±.010 BS 2A 266 to 2A 271:2016 • © The British Standards Institution 2016 BRITISH STANDARD 0604 0605 0606 0607 0608 0609 0610 0611 0612 0613 0614 0615 0616 0617 0618 0619 0620 0621 0622 0623 0624 0625 0626 0627 0628 0629 0630 0631 0632 Dia/length code Table 250 312 375 438 500 562 625 688 750 812 875 938 1.000 1.062 1.125 1.188 1.250 1.312 1.375 1.438 1.500 1.562 1.625 1.688 1.750 1.812 1.875 1.938 2.000 891 954 1.016 1.079 1.141 1.203 1.266 1.329 1.391 1.453 1.516 1.579 1.641 1.703 1.766 1.829 1.891 1.953 2.016 2.079 2.141 2.203 2.266 2.329 2.391 2.453 2.516 2.579 2.641 3/8–24 UNJF L ±.010 E ±.015 676 739 801 864 926 988 1.051 1.114 1.176 1.238 1.301 1.364 1.426 1.488 1.551 1.614 1.676 1.738 1.801 1.864 1.926 1.988 2.051 2.114 2.176 2.238 2.301 2.364 2.426 M ±.010 0704 0705 0706 0707 0708 0709 0710 0711 0712 0713 0714 0715 0716 0717 0718 0719 0720 0721 0722 0723 0724 0725 0726 0727 0728 0729 0730 0731 0732 Dia/length code (4 of 6) 250 312 375 438 500 562 625 688 750 812 875 938 1.000 1.062 1.125 1.188 1.250 1.312 1.375 1.438 1.500 1.562 1.625 1.688 1.750 1.812 1.875 1.938 2.000 906 968 1.031 1.094 1.156 1.218 1.281 1.344 1.406 1.468 1.531 1.594 1.656 1.718 1.781 1.844 1.906 1.968 2.031 2.094 2.156 2.218 2.281 2.344 2.406 2.468 2.531 2.594 2.656 7/16–20 UNJF L ±.010 E ±.015 Dimensions: lengths and optional hole position variables 741 803 866 929 911 1.053 1.116 1.179 1.241 1.303 1.366 1.429 1.491 1.553 1.616 1.679 1.741 1.803 1.866 1.929 1.991 2.053 2.116 2.179 2.241 2.303 2.366 2.429 2.491 M ±.010 – 0805 0806 0807 0808 0809 0810 0811 0812 0813 0814 0815 0816 0817 0818 0819 0820 0821 0822 0823 0824 0825 0826 0827 0828 0829 0830 0831 0832 Dia/length code – 312 375 438 500 562 625 688 750 812 875 938 1.000 1.062 1.125 1.188 1.250 1.312 1.375 1.438 1.500 1.562 1.625 1.688 1.750 1.812 1.875 1.938 2.000 – 1.094 1.157 1.220 1.282 1.334 1.407 1.470 1.532 1.594 1.657 1.720 1.782 1.844 1.907 1.970 2.032 2.094 2.157 2.220 2.282 2.344 2.407 2.470 2.532 2.594 2.657 2.720 2.782 – 904 967 1.030 1.092 1.144 1.217 1.280 1.342 1.404 1.467 1.530 1.592 1.654 1.717 1.780 1.842 1.904 1.967 2.030 2.092 2.154 2.217 2.280 2.342 2.404 2.467 2.530 2.592 Dimensions in inches 1/2–20 UNJF L ±.010 E ±.015 M ±.010 BRITISH STANDARD BS 2A 266 to 2A 271:2016 © The British Standards Institution 2016 • 0634 0636 0638 0640 0642 0644 0646 0648 0650 0652 0654 0656 0658 0660 0662 0664 0666 0668 0670 0672 0674 0676 0678 0680 0682 0684 0686 0688 0690 Dia/length code Table 2.125 2.250 2.375 2.500 2.625 2.750 2.875 3.000 3.125 3.250 3.375 3.500 3.625 3.750 3.875 4.000 4.125 4.250 4.375 4.500 4.625 4.750 4.875 5.000 5.125 5.250 5.375 5.500 5.625 2.766 2.891 3.016 3.141 3.266 3.391 3.516 3.641 3.766 3.891 4.016 4.141 4.266 4.391 4.516 4.641 4.766 4.891 5.016 5.141 5.266 5.391 5.516 5.641 5.766 5.891 6.016 6.141 6.266 3/8–24 UNJF L ±.010 E ±.015 2.551 2.676 2.801 2.926 3.051 3.176 3.301 3.426 3.551 3.676 3.801 3.926 4.051 4.176 4.301 4.426 4.551 4.676 4.801 4.926 5.051 5.176 5.301 5.426 5.551 5.676 5.801 5.926 6.051 M ±.010 0734 0736 0738 0740 0742 0744 0746 0748 0750 0752 0754 0756 0758 0760 0762 0764 0766 0768 0770 0772 0774 0776 0778 0780 0782 0784 0786 0788 0790 Dia/length code (5 of 6) 2.125 2.250 2.375 2.500 2.625 2.750 2.875 3.000 3.125 3.250 3.375 3.500 3.625 3.750 3.875 4.000 4.125 4.250 4.375 4.500 4.625 4.750 4.875 5.000 5.125 5.250 5.375 5.500 5.625 2.781 2.906 3.031 3.156 3.281 3.406 3.531 3.656 3.781 3.906 4.031 4.156 4.281 4.406 4.531 4.656 4.781 4.906 5.031 5.156 5.281 5.406 5.531 5.656 5.781 5.906 6.031 6.156 6.281 7/16–20 UNJF L ±.010 E ±.015 Dimensions: lengths and optional hole position variables 2.616 2.741 2.866 2.991 3.116 3.241 3.366 3.491 3.616 3.741 3.866 3.991 4.116 4.241 4.366 4.491 4.616 4.741 4.866 4.991 5.116 5.241 5.366 5.491 5.616 5.741 5.866 5.991 6.116 M ±.010 0834 0836 0838 0840 0842 0844 0846 0848 0850 0852 0854 0856 0858 0860 0862 0864 0866 0868 0870 0872 0874 0876 0878 0880 0882 0884 0886 0888 0890 Dia/length code 2.125 2.250 2.375 2.500 2.625 2.750 2.875 3.000 3.125 3.250 3.375 3.500 3.625 3.750 3.875 4.000 4.125 4.250 4.375 4.500 4.625 4.750 4.875 5.000 5.125 5.250 5.375 5.500 5.625 2.907 3.032 3.157 3.282 3.407 3.532 3.657 3.782 3.907 4.032 4.157 4.282 4.407 4.532 4.657 4.782 4.907 5.032 5.157 5.282 5.407 5.532 5.657 5.782 5.907 6.032 6.157 6.282 6.407 2.717 2.842 2.967 3.092 3.217 3.342 3.467 3.592 3.717 3.842 3.967 4.092 4.217 4.342 4.467 4.592 4.717 4.842 4.967 5.092 5.217 5.342 5.467 5.592 5.717 5.842 5.967 6.092 6.217 Dimensions in inches 1/2–20 UNJF L ±.010 E ±.015 M ±.010 BS 2A 266 to 2A 271:2016 10 ã â The British Standards Institution 2016 BRITISH STANDARD 0692 0694 0696 Dia/length code Table 5.750 5.875 6.000 6.391 6.516 6.641 3/8–24 UNJF L ±.010 E ±.015 6.176 6.301 6.426 M ±.010 0792 0794 0796 Dia/length code (6 of 6) 5.750 5.875 6.000 6.406 6.531 6.656 7/16–20 UNJF L ±.010 E ±.015 Dimensions: lengths and optional hole position variables 6.241 6.366 6.491 M ±.010 0892 0894 0896 Dia/length code 5.750 5.875 6.000 6.532 6.657 6.782 6.342 6.467 6.592 Dimensions in inches 1/2–20 UNJF L ±.010 E ±.015 M ±.010 BRITISH STANDARD BS 2A 266 to 2A 271:2016 © The British Standards Institution 2016 • 11 BS 2A 266 to 2A 271:2016 BRITISH STANDARD BS part number Part No shall be contiguous (i.e no spaces), for example A268D0416X (see Figure 3) Figure Example of part number call up Indentification and marking 5.1 The bolts shall have the manufacturer’s identification and BS part number applied to the upper face of the head, except for the 10–32 UNJF size, in which case the diameter code (03) may be omitted The special features code shall be omitted, as it is physically apparent 5.2 The method of marking bolts and packages shall be as specified in BS A 101 NOTE Figure 12 • Figure shows a typical dispersion of the various markings Typical dispersion of the various markings © The British Standards Institution 2016 BRITISH STANDARD BS 2A 266 to 2A 271:2016 Bibliography Further reading Def Stan 01-5, Fuels, lubricants and associated products Def Stan 00-970 Pt.1/12 Section Leaflet 8, Protection of structure – the penetration of titanium alloys by solid cadmium â The British Standards Institution 2016 ã 13 BS 2A 266 to 2A 271:2016 14 ã â The British Standards Institution 2016 BRITISH STANDARD This page deliberately left blank This page deliberately left blank NO 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