1、BRITISH STANDARD CONFIRMED APRIL1998 BS 2SP 7: 1943 (CancellingBS Specification BSSP7.) Incorporating Amendment Nos. 1, 2, 3 and 4 Specification for Aircraft Material Fork Joints (HighTensile Type) (ForSizes No. 4 B.A. to 3 / 4 inch B.S.F.inclusive) NOTEThe Institution desires to call attention to t
2、he fact 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.BS2SP7:1943 This Specification having been approved by the Aircraft IndustryCommitt
3、ee was published by the authority of theCouncil of the Institution asaBritish Standard on 19February 1943 BSI 05-2000 ISBN058034446 0 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. C
4、ompliance 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 8 and a back cover. This standard has been updated (see copyright date) and may have had amendments i
5、ncorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date Comments 629 May 1947 2714 February 1957 4084 February 1961 6220 July 1967 Indicated by a sideline in the marginBS2SP7:1943 BSI 05-2000 i Contents Page 1 Manufactur
6、e 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 preparation of
7、mechanical test samples 2 16 Mechanical tests 2 17 Hardness tests 3 18 Magnetic crack detection 3 Table 1 Fork Joints (High Tensile Type) 4 Table 2 Fork Joints (High Tensile Type) 6 Table 3 Fork Joints (High Tensile Type) 7 Table 4 Fork Joints (High Tensile Type) 8ii blankBS2SP7:1943 BSI 05-2000 1 N
8、OTEThe order must state the material classification letter and part number of the fork joints required in accordance with Clause5. 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 b
9、e tapped either right hand or left hand as 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 Tabl
10、e III of BS Specification No.93 forBritish Association Threads, or Table12of 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
11、All parts in non-corrosion resisting steel shall be uniformly coated with cadmium in accordance with the 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 Th
12、e finished fork joints selected as specified in Clause4 shall be screwed on to the wire as far as theinspection hole in the case of sizes up to and including 1 / 2in. and as far as the commencement of the gap in the case of sizes 9 / 16in. and over, and the axial load shall be applied to a pin place
13、d through the holes in the fork joints, no part of the fork joint being gripped in the testing machine. When loaded in this manner the fork joints shall show an ultimate strength not less than that given in Table 1 (Col.25) Table 2 (Col.23) Table 3 (Col.25) and Table 4 (Col.24). 6 Marking All fork j
14、oints 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 stainless steel they shall in addition be marked with the letter “Z” preceding thepart number. NOTEFor ordering purposes a letter “Y” shall be ins
15、erted 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 resisting and corrosion resisting parts. For example, the complete Part Reference Number for 5 / 16in. non-corrosion resistin
16、g fork joint (left-hand thread) is BS SP7 Y/GL and for corrosion resisting steel BSSP7Z/GL, while the corresponding markings on the actual fork joint will be GL and Z/GL. FORK JOINTS MACHINED FROM BAR 7 Material Fork joints machined from bar shall be made from steel bars which have been inspected an
17、d passed bythe Inspector as complying with the latest issue of BS Specification BSS94, BSS96, BSS114 orBSS117 (B.) or BS Specification BSS80 where corrosion resisting steel is specified. 8 Manufacture Fork joints shall be machined bright all over. 9 Design and dimensions All fork joints (those in no
18、n-corrosion resisting steelafter coating) shall be in accordance with thedimensions and limits given inTable 1 and Table 2orTable 3 andTable 4, with the exception that those made in stainless steel shall have the collar (D) and projection (W) omitted. FORK JOINTS MADE BY THE “COLD HEADING” PROCESS (
19、for SIZES 4 B.A. to 13 / 32 in. ONLY). 10 Material a) The fork joints shall be machined from blanks made from steel of the following chemical compositions 2) : 1) Ministry of Technology, Process Specification DTD904 for cadmium plating. Carbon not less than 0.30 nor morethan0.45 per cent. Silicon no
20、t less than 0.10 nor morethan0.35 per cent. Manganese not more than 1.50 per cent. 2) Steel of this composition is covered by BS970 En. 8.BS2SP7:1943 2 BSI 05-2000 b) The complete analysis of every cast shall be supplied to the Inspector. c) When corrosion resisting steel fork joints are required, t
21、he steel shall comply with the chemical composition of BSS80. 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 steelafter coating) shall be in accordance with t
22、he dimensions and limits given inTable 3 andTable 4, 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 no
23、twithstanding that ithas been passed previously 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 me
24、chanical test samples a) Blanks hardened 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
25、 period or a length of wire from which these blanks have been made, and which has been hardened and tempered with the blanks represented. The test pieces machined from the selected blanks or lengths of wire in accordance with Clause16 c) shall comply with the mechanical test requirements ofClause16.
26、 b) Blanks hardened by a continuous process 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 larg
27、est diameter from the tempered batch or a length of wire from which the largest blanks in the tempered batch have been made. The test pieces machined fromthe selected blanks or lengths of wire in accordance with Clause16 c) shall comply with the mechanical test requirements of Clause16. c) If any te
28、st piece fails to meet the mechanical tests, two further samples selected as in paragraph a) or b) above shall be submitted to the mechanical tests specified in Clause16. If either of these test pieces fails to meet the mechanical tests specified the blanks represented may be rejected or, at the req
29、uest of the manufacturer, be re-heat treated and re-tested in accordance 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 machi
30、ned from the selected samples to the dimensions of the largest possible size of theBritish Standard tensile test piece Figures1,2,3or4of British Standard Specification No.2A4. Alternatively, at the option of the manufacturer the tensile test maybe made on the full cross section of the unmachined tes
31、t sample. d) i) Izod test. The Izod test pieces shall be machined from the selected samples to the dimensions of the British Standard notched bar test piece Figure7or10 of British Standard Specification No.2A4 and tested ina 120 ft. lb. Izod machine. ii) When the dimensions of a test sample are such
32、 that neither of the British Standard notched bar test pieces can be made from it, the nicked fracture test see paragraph e) shallbe substituted for the Izod test. Sulphur not more than 0.06 per cent. Phosphorus not more than 0.06 per cent. 3) Steel with chemical composition of BSS 80 is covered by
33、BS970 En. 57. Ultimate Tensile Stress Not less than 55 and not more than 65 tons per sq. in. Elongation on4 Not less than 15 per cent. Izod Not less than 40 ft. lb. Nicked fracture See paragraph e) below. ABS2SP7:1943 BSI 05-2000 3 e) Nicked fracture test. A test piece, nicked orsawn so that the are
34、a of the portion to be fractured is not less than one-half of the original sectional 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 In
35、spector. When continuous tempering is employed the blanks shall be selected for hardness tests at regular intervals and when tempered in batches the blanks shall be selected from each tempered batch. The hardness numbers obtained must be not less than248and not more than302on the Brinell Scale or th
36、eir equivalent values on the scale of themethod adopted. 18 Magnetic crack detection Each blank shall be subjected to an examination by means 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
37、 freedom from cracks.BS 2 SP 7:1943 4 BSI 05-2000 Table 1 Fork Joints (High Tensile Type) (No.4 B.A. to 1 / 2in. B.S.F. inclusive) NOTEThe centre of the pinhole A and the centre line of the slot P must be within 0.010 inch of the centre lineoftheFork Joint. The Inspection Hole H must be drilled at r
38、ight angles to the axis of the Fork Joint at thespecifieddistance M from the end of the shank. Its actual position on the circumference of the shank may be determined by convenience of manufacture. Sketch showing Fork Joint with collar D omitted as manufacturing mark for Fork Joints made in corrosio
39、n resisting Steel.BS 2 SP 7:1943 BSI 05-2000 5 Table 1 Fork Joints (High Tensile Type) (No.4 B.A. to 1 / 2in. B.S.F. inclusive) 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 26 27 Part No. (See Footnote) Size of ForkJoint. A B C D E F G H J K L M N P Q R S T U V X Y Minimum Ultim
40、ate Tensile Strength. Approx. Weight. a Part No. of Standard Pin. (see latest issue of BS Specification BS SP 4.) Rt. Hd. Thd. Lt. Hd. Thd. + .001 + .005 0 + .01 0 + .01 0 + .015 0 + .015 0 + .015 0 + .04 0 + .015 0 + .04 0 + .04 0 + .015 0 + .01 0 + .01 0 + .01 0 + .04 Right Hand orLeft Hand Thread
41、. Pin Drill Rad. a 0 + .01 .01 + .01 in. in. in. in. in. in. in. in. in. in. in. in. in. in. in. in. in. in. in lb. lb. B BL 4 B.A. 5 / 32 5 / 32 .24 .07 .28 .05 .36 1 / 16 .33 .30 .21 .31 .25 .07 .03 .18 .18 1.20 4 B.A. .24 .20 .05 1,155 .010 A 2 C CL 2” 3 / 16 3 / 16 .29 .08 .33 .05 .44 1 / 16 .38
42、 .35 .24 .34 .30 .10 .04 .22 .22 1.30 2” .28 .25 .05 2,090 .015 B 3 D DL b 7 / 32 in. B.S.F. 7 / 32 15 / 64 .35 .10 .40 .05 .48 1 / 16 .48 .45 .29 .39 .36 .11 .07 .24 .26 1.44 7 / 32 in. B.S.F. .32 .29 .07 2,860 .030 C 4 E EL 1 / 4 ” 1 / 4 17 / 64 .39 .11 .45 .05 .56 1 / 16 .55 .50 .33 .43 .41 .125
43、.08 .28 .30 1.53 1 / 4 ” .37 .33 .08 3,795 .045 D 5 F FL b 9 / 32 ” 9 / 32 19 / 64 .44 .12 .50 .05 .60 1 / 16 .60 .55 .36 .46 .46 .14 .11 .30 .34 1.63 9 / 32 ” .41 .38 .08 5,115 .065 E 6 G GL 5 / 16 ” 11 / 32 21 / 64 .48 .12 .55 .05 .70 1 / 16 .70 .65 .40 .50 .50 .14 .12 .35 .40 1.74 5 / 16 ” .49 .4
44、2 .09 6,270 .095 G 7 H HL b 11 / 32 ” 11 / 32 23 / 64 .53 .15 .60 .05 .70 1 / 16 .75 .65 .45 .55 .55 .17 .17 .35 .43 1.80 11 / 32 ” .51 .45 .10 7,865 .110 G 8 J JL 3 / 8 ” 13 / 32 25 / 64 .59 .15 .67 .05 .82 1 / 16 .87 .75 .48 .58 .60 .17 .17 .41 .48 1.95 3 / 8 ” .57 .51 .10 9,350 .140 J 9 K KL b 13
45、 / 32 ” 7 / 16 27 / 64 .63 .15 .71 .05 .88 1 / 16 .97 .85 .51 .61 .63 .188 .20 .44 .55 2.07 13 / 32 ” .63 .55 .10 11,275 .160 K 9 L LL 7 / 16 ” 15 / 32 29 / 64 .68 .15 .76 .05 .92 1 / 16 1.05 .90 .54 .64 .68 .188 .23 .46 .59 2.15 7 / 16 ” .69 .60 .10 12,980 .195 L 10 M ML b 15 / 32 ” 1 / 2 31 / 64 .
46、72 .15 .80 .05 .98 1 / 16 1.10 .95 .57 .67 .72 .219 .26 .49 .64 2.22 15 / 32 ” .73 .64 .10 15,180 .230 M 11 N NL 1 / 2 ” 17 / 32 33 / 64 .77 .15 .85 .05 1.06 1 / 16 1.20 1.05 .60 .70 .77 .25 .26 .53 .67 2.35 1 / 2 ” .78 .69 .10 17,050 .270 N 13 NOTEWhere Fork Joints are manufactured in corrosion res
47、isting Steel (S 80) the Part Numbers must bear the prefix letter “Z” e.g., Z/D, Z/DL. a The figures in Cols. 22 and 26 are given for the information of designers and not for purposes of inspection. b These sizes are obsolescent and must not be used for new designs.BS 2 SP 7:1943 6 BSI 05-2000 Table
48、2 Fork Joints (High Tensile Type) 9 / 16 in. to 3 / 4in. B.S.F. inclusive NOTESThe centre of the pinhole A and the centre line of the slot P must be within 0.010 inch of the centre line of the Fork Joint. Sketch showing Fork Joint with collar D omitted as manufacturing mark for ForkJoints made in co
49、rrosion resisting Steel. 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. (See Footnote) Size of ForkJoint. A B C D E F G L N P Q R S T U V W X Y Z Minimum Ultimate Tensile Strength. Approx. Weight. a Part No. of Standard Pin. (see latest issueof BS Specification BSSP 4.) Rt. Hd. Thd. Lt. Hd. Thd. + .001 + .005 .005 0 + .015 0 + .015 0 + .015 0 + .02 0 + .04 0 + .015 0 + .01 0 + .01 0 + .01 0 + .04 Right-Hand or Left-Hand Thread. Pin
