1、BRITISH STANDARD CONFIRMED APRIL 1998 BS 3SP 3:1943 Incorporating Amendment Nos. 1, 2 and 3 (Cancelling BS Specification 2 SP 3.) Specification for Aircraft Material Fork joints (lowtensile type) (forsizes No.4B.A. to 1 / 2inch B.S.F. inclusive) NOTEThe Institution desires to call attention to the f
2、act that this Specification is intended to include the technical provisions necessary for the supply of the articles herein referred to, but does not purport to comprise all the necessary provisions of a contract. UDC 629.13.01:621.825.6BS3SP3:1943 This Specification having been approved by the Airc
3、raft IndustryCommittee was published by theauthority of theCouncil of theInstitution asaBritishStandard on 19 February 1943 BSI 05-2000 ISBN 0 580 34456 8 A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their c
4、orrect 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 1 to 7 and a back cover. This standard has been updated (see copyright date) and may
5、have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue Comments 632 May 1947 6218 July 1967 1797 August 1975 Indicated by a sideline in the marginBS3SP3:1943 BSI 05-2000 i Contents Page 1 M
6、anufacture 1 2 Screw threads 1 3 Anti-Corrosion treatment 1 4 Selection for testing 1 5 Mechanical test 1 6 Marking 1 7 Material 1 8 Manufacture 1 9 Design and dimensions 1 10 Material 1 11 Manufacture 2 12 Design and dimensions 2 13 Freedom from defects 2 14 Heat treatment 2 15 Selection and prepar
7、ation of mechanical test samples 2 16 Mechanical tests 2 17 Hardness tests 3 18 Magnetic crack detection 3 Table 1 Fork Joints 4 Table 2 Alternative design of low tensile fork joints for use with the “cold heading” process of manufacture 6ii blankBS3SP3:1943 BSI 05-2000 1 NOTEThe order must state th
8、e material classification letter and part number of the fork joints required in accordance withclause5. 1 Manufacture Fork joints may, at the option of the manufacturer, be made by machining either from bar or from blanks produced by the “cold heading” process. Theyshall be tapped either right hand
9、or left handas specified on the order. 2 Screw threads The screw threads of coated fork joints in non-corrosion resisting steel and those of fork joints in corrosion resisting steel shall not be smaller than the minimum full, effective and core diameters specified in TableIII of BS Specification No.
10、93 forBritish Association Threads, or Table12 of BSSpecification No.84 for British Standard Fine Threads. The screw threads of all fork joints (thosein non-corrosion resisting steel after being coated) shall be required to pass approved gauges. 3 Anti-Corrosion treatment All parts in non-corrosion r
11、esisting steel shall be uniformly coated with cadmium in accordance withthe requirements of specification DTD904 1) . 4 Selection for testing Samples of fork joints may be selected at the discretion of the Inspector and tested as specified inClause5. 5 Mechanical test The finished fork joints select
12、ed as specified in Clause 4 shall be screwed on to the wire as far as the inspection hole and the axial load shall be applied to a pin placed through the holes in the fork joint, no part of the fork joint being gripped in the testing machine. When loaded in this manner the fork joints shall show an
13、ultimate tensile strength notless than that given inTable 1 (Col. 23) andTable 2 (Col. 23). 6 Marking All fork joints shall have the appropriate part number applied on the shank near the tapped endby rolling and shall also bear the mark of the Inspector. If made of corrosion resisting steel they sha
14、ll in addition be marked with the letter “Z” preceding the part number. NOTEFor ordering purposes a letter “Y” shall be inserted in the Part Reference Number for non-corrosion resisting fork joints between the Specification Number and Part Number so as to distinguish clearly between non-corrosion re
15、sisting and corrosion resisting parts. For example, the complete Part Reference Number for 7 / 16in. non-corrosion resisting fork joint (left-hand thread) isS.P. 3Y/420L and for corrosion resisting steel S.P. 3Z/420L, while the corresponding markings on the actual fork joint willbe420L and Z/420L. F
16、ORK JOINTS MACHINED FROM BAR. 7 Material Fork joints machined from bar shall be made from steel bars which have been inspected and passed by the Inspector as complying with the latest issue ofBS Specification S. 1 or S. 96, or where corrosion resisting steel is specified from the latest issue of one
17、 of the following BS Specifications, S. 61, S. 62 orS. 80. 8 Manufacture Fork joints shall be machined bright all over. 9 Design and dimensions All fork joints (those in non-corrosion resisting steel after coating) shall be in accordance with the dimensions and limits given inTable 1 andTable 2, wit
18、h the exception that those made in corrosion resisting steel shall have the collar (D) and projection (W) omitted. FORK JOINTS MADE BY THE “COLDHEADING” PROCESS (forSIZES 4 B.A. to 3 / 16 in. ONLY). 10 Material a) The fork joints shall be machined from blanks made from steel of the following chemica
19、l compositions 2) : b) The complete analysis of every cast shall be supplied to the Inspector. 1) Ministry of Technology, Process Specification DTD 904 for cadmium plating. Carbon not less than 0.25 nor more than0.35 per cent. Silicon not less than 0.10 nor more than0.35 per cent. Manganese not less
20、 than 0.50 nor more than0.90 per cent. Sulphur not more than 0.06 per cent. Phosphorus not more than 0.06 per cent. 2) Steel of this composition is covered by BS 970 En. 5.BS3SP3:1943 2 BSI 05-2000 c) When corrosion resisting steel fork joints are required, the steel shall comply with the chemical c
21、omposition S. 61, S. 62 or S. 80. 3) 11 Manufacture The blanks shall be made by an approved process from material in a suitably softened condition. 12 Design and dimensions All fork joints (those in non-corrosion resisting steel after coating) shall be in accordance with the dimensions and limits gi
22、ven inTable 2, with the exception that those made in corrosion resisting steel shall have the projection (W) omitted. 13 Freedom from defects a) The fork joints shall be free from defects. b) Any fork joint may be rejected at any time forfaults in manufacture notwithstanding thatit has been passed p
23、reviously on chemical composition and mechanical tests. 14 Heat treatment a) All blanks before machining shall be hardened and tempered to the required ultimate strength. b) No blanks shall be re-hardened more than three times. 15 Selection and preparation of mechanical test samples a) Blanks harden
24、ed and tempered by a continuous process. During each period of continuous heat treatment not exceeding8hours, at least one test sample shall be selected. This test sample shall be either one of the blanks of the largest diameter that has been treated during this period or a length of wire from which
25、 these blanks have been made, and which has been hardened and tempered withthe blanks represented. The test pieces machined from the selected blanks or lengths ofwire in accordance with Clause16 c) shall comply with the mechanical test requirements ofClause16. b) Blanks hardened by a continuous proc
26、ess or in batches and tempered in batches comprising one tempering furnace charge. Sufficient test samples shall be hardened with the blanks to enable at least one test sample to be tempered with each batch. This test sample may be either one blank of the largest diameter from the tempered batch or
27、a length of wire from which the largest blanks in the tempered batch have been made. The test pieces machined from the selected blanks or lengths of wire in accordance with Clause16 c) shall comply with the mechanical test requirements of Clause16. c) If any test piece fails to meet the mechanical t
28、ests, two further samples selected as in paragraph a) orb) above shall be submitted tothe mechanical tests specified in Clause16. Ifeither of these test pieces fails to meet the mechanical tests specified the blanks represented may be rejected or, at the request of the manufacturer, be re-heat treat
29、ed and re-tested inaccordance with Clause8. 16 Mechanical tests a) All tests shall be carried out to the satisfaction of the Inspector. b) The mechanical properties of the material shall be as follows: c) Tensile test. The tensile test pieces shall be machined from the selected samples to the dimens
30、ions of the largest possible size of the British Standard tensile test piece Figures 1, 2, 3 or 4 of British Standard Specification No. 2 A 4. Alternatively, at the option of the manufacturer the tensile test may be made on the full cross section of the unmachined test sample. d) i) Izod test. The I
31、zod test pieces shall be machined from the selected samples to the dimensions of the British Standard notched bar test piece Figures7 or10 of British Standard Specification No.2A4 and tested ina120ft. lb. Izod machine. ii) When the dimensions of a test sample are such that neither of the British Sta
32、ndard notched bar test pieces can be made from it, the nicked fracture test see paragraph e) shall be substituted for the Izod test. 3) Steel with chemical composition of S. 61 is covered by En. 56A, S. 62 by En. 56 and S. 80 by En. 57 all of BS 970. Ultimate Tensile Stress Not less than 35 tons per
33、 sq. in. Elongation on 4 Not less than 15percent. Izod Not less than 40 ft. lb. Nicked fracture See paragraph e) below. ABS3SP3:1943 BSI 05-2000 3 e) Nicked fracture test. A test piece, nicked orsawn so that the area of the portion to be fractured is not less than one-half of the original sectional
34、area, must be free from defects when broken by a minimum number of blows. 17 Hardness tests Hardness tests shall be carried out by an approved method on representative hardened and tempered blanks selected by the Inspector. When continuous tempering is employed the blanks shall be selected for hardn
35、ess tests at regular intervals and when tempered in batches the blanks shall be selected from each tempered batch. The hardness numbers obtained must indicate uniformity of heat treatment among the batches ofblanks. 18 Magnetic crack detection Each blank shall be subjected to an examination by means
36、 of an electro-magnetic crack detector of a type approved by the Deputy Director General of Aeronautical Inspection and shall be thoroughly inspected to verify freedom from cracks.BS 3SP 3:1943 4 BSI 05-2000 Table 1 Fork Joints (Low Tensile Type.) NOTESThe centre of the pinhole A and the centre line
37、 of the slot P must be within 0.010 inch of the centre line of the Fork Joint. The Inspection Hole (H) must be drilled at right angles to the axis of the Fork Joint at the specified distance M from the end of the shank. Its actual position on the circumference of the shank may be determined by conve
38、nience of manufacture.BS 3SP 3:1943 BSI 05-2000 5 Table 1 Fork Joints (Low Tensile Type.) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Part No. (SeeFootnote) Size of Fork Joint. A B C D E F G H J K L M N P Q R S T U Right-Hand or Left-Hand Thread V Pin Drill Rad. b Minimum Ultim
39、ate Tensile Strength. Approx. Weight. b Part No. of Standard Pin. (see latest issue ofBS Specification SP 4) Rt. Hd. Thd. Lt. Hd. Thd. + .001 + .005 0 + .01 0 + .01 0 + .015 0 + .015 0 + .04 0 + .015 0 + .04 0 + .04 0 + .015 0 + .01 0 + .01 0 + .01 0 + .04 in. in. in. in. in. in. in. in. in. in. in.
40、 in. in. in. in. in. in. in. in. in. lb. lb. 412 412 L. 4 B.A. 5 / 32 5 / 32 .23 .07 .28 .05.36 1 / 16 .40 .35 .20 .30 .26 .10 .04 .18 .19 1.1 4 B.A. .23 1 155 .010 A 2 413 413 L. 2” 3 / 16 3 / 16 .28 .08 .32 .05.48 1 / 16 .50 .40 .25 .35 .33 .15 .06 .24 .24 1.3 2” .31 2 090 .016 B 3 411 411 L. B.S.
41、F. 7 / 32 c in. 7 / 32 15 / 64 .34 .10 .40 .05.56 1 / 16 .53 .48 .25 .35 .42 .20 .05 .28 .27 1.5 in. 7 / 32B.S.F. .34 2 860 .030 C 5 414 414 L. 1 / 4 ” 1 / 4 17 / 64 .385 .11 .48 .05.62 1 / 16 .60 .50 .30 .40 .48 .20 .08 .31 .30 1.5 1 / 4 ” .39 3 795 .046 D 6 415 415 L. 9 / 32 c ” 9 / 32 19 / 64 .44
42、 .12 .50 .05.72 1 / 16 .78 .60 .30 .40 .58 .20 .08 .36 .34 1.7 9 / 32 ” .45 5 115 .076 E 8 416 416 L. 5 / 16 ” 11 / 32 21 / 64 .49 .12 .56 .05.86 1 / 16 .78 .70 .35 .45 .68 .25 .05 .43 .37 1.85 5 / 16 ” .50 6 270 .104 G 10 417 417 L. 11 / 32 ac ” 11 / 32 23 / 64 .54 .15 .62 .05.90 1 / 16 .78 .70 .35
43、 .45 .73 .25 .09 .45 .39 1.90 11 / 32 ” .55 7 865 .135 G 11 418 418 L. 3 / 8 a ” 13 / 32 25 / 64 .58 .15 .66 .051.00 1 / 16 .90 .80 .40 .50 .78 .30 .12 .50 .44 2.1 3 / 8 ” .62 9 350 .168 J 12 419 419 L. 13 / 32 ac ” 7 / 16 27 / 64 .63 .15 .71 .051.06 1 / 16 1.05 .95 .45 .55 .78 .34 .13 .53 .54 2.35
44、13 / 32 ” .67 11 275 .208 K 12 420 420 L. 7 / 16 a ” 15 / 32 29 / 64 .68 .15 .76 .051.14 1 / 16 1.1 1.0 .45 .55 .83 .36 .18 .57 .58 2.45 7 / 16 ” .74 12 980 .250 L 13 421 421 L. 15 / 32 ac ” 1 / 2 31 / 64 .73 .15 .81 .051.20 1 / 16 1.25 1.1 .50 .60 .93 .38 .13 .60 .62 2.6 7 / 16 ” .74 15 180 .293 M
45、15 422 422 L. 1 / 2 a ” 17 / 32 33 / 64 .77 .15 .85 .051.26 1 / 16 1.3 1.17 .55 .65 .98 .40 .18 .63 .64 2.7 1 / 2 ” .81 17 050 .334 N 16 a The Institution recommends that these sizes be ultimately replaced by Fork Joints in high tensile steel. b The figures in Cols. 22 and 24 are given for the infor
46、mation of designers and not for purposes of inspection. c These sizes are obsolescent and must not be used in new designs. Where Fork Joints are manufactured in Corrosion Resisting Steel (S 61, S 62 or S 80 the Part Numbers must bear the prefix letter “Z” e.g., Z/412, Z/412 L.0 .015 +0 .015 +0 .015
47、+.010 .005 +0 .015 +0 .015 +0 .015 +.010 .005 +.010 .005 +0 .015 +0 .015 + .020 0 +BS 3SP 3:1943 6 BSI 05-2000 Table 2 Alternative design of low tensile Fork Joints for use with the “cold heading” process of manufacture NOTESThe centre of the pinhole A and the centre line of the slot P must be withi
48、n 0.010 inch of the centre line of the Fork Joint. The Inspection Hole H must be drilled at right angles to the axis of the Fork Joint at the specified distance M from the end of the shank. Its actual position on the circumference of the shank may be determined by convenience of manufacture.BS 3SP 3
49、:1943 BSI 05-2000 7 Table 2 Alternative design of low tensile Fork Joints for use with the “cold heading” process of manufacture 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 22A 22B 23 24 25 Part No. Size of Fork Joint. A B C D E F G H J K L M N P Q R S T U Right-Hand or Left-Hand Thread V Pin Drill Rad. a W X Minimum Ultimate Tensile Strength Approx. Weight. a Part No. of Standard Pin. (see latest issue of BS Specification SP 4.) Rt Hd. Thd. Lt. Hd. Thd. + .001 + .005 0 + .01 0 + .01 0
