1、BRITISH STANDARD SPECIFICATION GENERAL PURPOSE ACME SCREW THREADS B.S. 1104 : 1957 incorporating amendments issued July A965 (PD 5555). December 1965 (PD 5707) and March 1966 (PD 5795) Price 10)- net I I BRITISH STANDARDS INSTITUTION INCORPORATED BY ROYAL CHARIER BRITISH STANDARDS HOUSE, 2 PARK ST.,
2、 LONDON, W.1 TELEGRAMS: STANDARDS LONDON WI TELEPHONE: 01-629 9ooo BEST COPY AVAILABLE BSI BS*3304 57 Lb24669 0549332 44 B.S. 1104 : 1957 THIS BRITISH STANDARD, having been approved by the Mechanical Engineering indusy Standards Committee and endorsed b) the Chairmm of the Engineering Divisional Cou
3、ncil, was published under the authority of the General Council on 5th June, 957. First published 1943. First revision June 1957. The Institution desires to call attention to the fact that this British Standard does not purport ta include all the necessary provisions of a contract. In order to keep a
4、breast of progress in the industries concerned, British Standards are subject to periodical review. Suggestions for improvements WU be recorded and in due course brought to the notice of the committees charged with the revision of the standards to which they refer. A complete list of British Standar
5、ds, numbering oser 4OO0, indexed and cross-indexed for reference, together with an abstract of each standard, will be found in the Institutions Yearbook, price 15s. For the purpose of converting British units to theu metric equivalents the tables given in B.S. 350, Conversion factors and tables . sh
6、ould be used. This standard makes reference to the following British Standard : B.S. 2517. Definitions for use in mechanical engiiieerhg. British Standarcis are revised, when necessary, by the issue either of amendment slips or of revised editions. It is important that users of British Standardi sho
7、uld ascertain that they are in possession of the latest amendments or editidm. 7 Previous page is blank BSI BS*LLOLi 57 I1624669 0549313 785 B.S. 1104 : 1957 CO-OPER4TING ORGANIZATIONS The Mechanical Engineering Industry Standards Com- mittee, under whose supenisian this British Standard was prepare
8、d, consists of representatives from the following Government departments and scientific aiid industrial organizations :- *Admiralty *Air Ministry Associated Ofices Technical Committee Association of Consulting Engineers (Incorporated) British Chemical Plant Manufacturers Association British Compress
9、ed Air Society *British Electrical and Allied Manufacturers Association *British Engineen Association British Internal Combustion Engine Manufacturers Association British Iron and Stl Federation *Briti$h Railways, The British Transport Commission Central Electricity Authority and Area Boards Crown A
10、gents for Oversea Governments and Adnunistrations *D.S.l.R.-Mechanical Engineering Research Laboratory *Engineering Equipment Users Association Gas Council High Commissioner of India Institute of Marine Engineers Institute of Petroleum Institution of Civil Engineers Institution of Gas Engineers Inst
11、itution of Heating and Ventilating Engineers *Institution of Mechanical Engineers Institution of Mechanical Eng,ineers (Automobile Division) *Institution of Production Engineers *Locomotive and Allied Manufacturers Association of Great Britain *Machine Tool Trades Association Ministry of Pol-r Minis
12、try of Lah 7%: and National Service (Factory Inspectorate) *Ministry of Supp:; Ministry of Transport and Civil Aviation Ministry of Works National Coal Board *National Physical Laboratory D.S.I.R. *Radio Industry Council War CIniCo The orgaoitations marked with an asterisk in the above list. togethe
13、r with the following. were directly represented on the Committee entrusted with the preparation of this standard :- Agricultural Engineers Association British Bolt, Nut, Screw and Rivet Feeration British Valve ManFfacturers Association Cut Thread Screwing Tool Manufacturers Association Engineering S
14、tandards Coordinating Committee Gauge and Tool Makers Association Ground Thread Tap Assrnialion National Association of Manne Engine Builden Radio Communication and Electro such threads do not form part of this standard. The limits and tolerances in this standard relate to sinsle-start Acme threads,
15、 and may be used, if considered suitable, for multi-start Acme threads. The latter threads are employed where single-start threads do not provide the fast relative traversing motion which is sometimes necessary. The recommended system for gauging the threads is to British principles and practice. SE
16、CrION ONE: SPECIFICATION OF ACME SCREW THREAD 1. This British Standard recommends a Standard Series of diameters and associated pitches for General Purpose Acme form screw threads, for the nominal size range W in. to 5 in. and specifies the limiting dimensions, tolerances and allovanccs for four cla
17、sses of thread. Information is also provided whereby the limiting dimensions for any other screw thread of Acme form niay be determined, but the use of these special diameterlpitch combinations should be avoided wherever possible. Recommendations are given in Section Two regarding the types and dime
18、nsions of gauges to be used. SCOPE DEFINITIONS 2. For the pirposes of this ritisli Standard the dcfinitioiis given in B.S. 2517, Definitions for use in mcchanical engineering, shall apply. The two definitions which follow are quoted from that standard. Pircli. The distance, measured pralle1 to the a
19、uk, betweeii corre- sponciini points on adjacent thread forms in the same axial plane section and on the same side of the axis. NOTE. Thc pitch (in inches) is the reciprocal of the number of the thrcads per inch. 0.9067 15 0.8967 0.8067 o. 8435 0.8335 .g 0.8233 0.8133 0-7933 0.7833 -U .i! 0.8033 -Cl
20、earance Basic dor db Basic effective dia Basic minor dia T - Clearance Class 2G 3C 4G 5G Nut tolerance zone Screw tolerance zone PL. 3 Dheral tolerances, clearances and plloiranfe for he four cW of genemi purpo Acme threads of 1 in. din.4 T P I - BSI BS*LL04 57 m Lb2Ybb9 0549324 560 m B.S. 1104 : 10
21、57 h. Class 2G k 0.04 0.04 0.03 0.03 0.02 0.02 0.01 0.01 O 0 0.01 0.01 0.02 002 0.03 003 004 0.04 0.05 0.05 0.06 O 06 Nomid riu lin 2 in Jin 4in Sin C!ass 3C in. 0.02 0.02 0.01 0.01 O 0 0.01 0.01 0.02 O2 0.03 0.03 Nominal size I in lin 3in 4m Sin 1 y.fie.ctiy ,b*w)l in. O02 O01 O 0.0 I 0.02 Class 4G
22、 in. I I 1 1 I I I , 7-1 0.02 0.01 0 0.01 0.02 Nominal sim lin 2 in 3 in 4m sin h. Class 5G in. 0.02 0.02 O01 0.01 O 0 0.01 0.01 0.02 0.02 Nominal Size lin 2in 3in 4in Sin Fig. 4. EBective diameter tolerances and allowances for the siandard seeries. I5 BSI BS*L104 57 W Lb24669 0549325 4T7 B.S. 1104
23、: 1957 TADLE I BASIC DIMENSIONS OF THE STANDARD SERIES OF GENERAL PURPOSE ACME SCREW THREADS (See Figs. i and 2) Ai u.leted Aiutch. 1966. I 1 !23 4 5 6 7 I- - ,_ I I I Wid7 I 9 ?O - .- - . . . . . . . _ _. . . -. - -. - - _. - - . -. _. -. Major diameter Eecire diameter Miwr diameter _-_ - -. -. . .
24、 .- . . -. . - . _. . . . . . . . -. -_ Mu. TOI. Min. _ _I.- . . . _ in. in. 0.1775 0.0073 04550 0.0091 O*Z17 5 0.009 4 0.380 O 0.009 6 om i o.ooa o in. 0*110 2 0.223 1 0.245 9 0.308 1 0.370 4 in. 1 in. j in. ia. ir . in. 0.2500 0.005 O 0.245 O 1 0.215 8 0.004 9 C 210 9 0.312 5 0405 O I 0.307 5 0.27
25、3 8 0.005 3 04685 0.3750 0.0050 I 0*3700 0.3213 0.0061 0.315 2 0.437 5 0.005 O I 0.432 5 0.383 8 0-006 3 0.377 5 0.5000 04050 0.4950 I 04458 0.0064 0.4394 1 I I 1- -t- 0.557 e 0.007 2 0.550 6 0.661 5 0008 1 0.653 4 0.910 7 0.008 5 0,902 2 0.786 1 ; O408 3 I , 0.717 8 0.480 O j 0.010 7 0.563 3 0.012
26、2 0.688 3 O412 5 0413 3 ! 0.012 7 04062 , 0.6188 0,0083 I 0.741 7 0.0083 , 0.8667 0.0083 0.9917 0.469 3 0.551 1 0.615 8 0800 6 0840 O 0.964 9 1.089 6 1.214 4 - 1.464 (i 1.713 6 1.878 3 2.121 9 - 2.377 6 2.457 9 2.957 4 3.456 8 3956 3 4,455 a 0625 O 0.750 O 0.875 O 1-OOo o - 1.125 O 1450 O 1.375 o 1.
27、500 o I 0.993 6 I 0-010 O 0.983 6 1 0855 O 0.015 O 1.118 3 1 0.010 1 1.108 f 0,980 O I 0.015 1 1.2327 1.1050 1 0.0154 1.357 3 , 1.230 O ! 0.015 6 1.112 5 1.237 5 1,362 5 1.487 5 - 1.737 5 1,987 5 2.253 3 2.483 3 - 2,733 3 2.916 3 3.475 a 3.975 a 3.475 O 4475 c 0.012 5 0.012 5 0012 5 0.012 5 - 0.012
28、5 0.012 5 0.016 7 0.016 1 - 0016 7 0.025 O 0.025 0.025 3 0.025 O 0.025 a I i I - 1417 1 1 0*0137 1.866 5 I 0.011 O 2-074 3 0.012 3 2.323 8 I 0.012 5 I -1- - 1.606 4 1455 5 2.062 o 2.311 3 - 0.016 O 0.016 4 0.018 4 0.018 8 1.750 O 2.m o 2.250 o 1.500 o - 2.750 O 3400 O 3.500 o 4.000 o 4-500 o 6.000 O
29、 - 1.480 O 1.730 O 1.896 7 2.146 2.573 4 2.739 5 3.238 8 3.738 o 4.237 3 4.136 4 0,012 7 0.014 7 0.015 1 0.015 5 0.01 6 2 0.015 a - 2.5607 2.3967 2.7248 I 2.4800 3.2237 I 2.9800 3-722 5 1 3 480 O 4,2215 3 9800 4.720 2 4:480 O 0.019 I 0.022 I 0.022 z 0.023 1 0.023 1 0.024 i - BSI BS* should be made a
30、nd the effective diameter equivalent, dO, of such error calculated from the formula d0 = 3.867 x 8,. The diametral play between the nut and the plug gauge should then be measured with the aid of a dial gauge to see that the total play is not less than de. 17. The tolerances on the diameters of Acme
31、thread gauges are given in Table 12. For all screw gauges for Classes 5G, 4G and 3G, the pitch error between any two threads not further apart than 1 in. shill not exceed 0.0002 inches. For gauges longer than 1 in. the cumdative pitch error shall not exceed the following amounts :- TOLFWCES FOR GAUG
32、ES 0403 in. for gauges over 1 in. up to and including 3 in. C4 in. for gauges over 3 in. up to and including 5 in. (0006 in. for gauges over 5 in. up to and including 10 in. For Class 2G gauges, O.OOO1 in. shall be added to each of the above values. Columq 5 of Table 12 gives the allowable tolerance
33、s on the flank-angles of the gauge thread. The deviation from the true thread form caused by such irregularities as convex or concave flanks of thread, or slight pro- jections on the thread form, shall not exceed the tolerances permitted on the flank angle. The tolerances on half-angle of thread are
34、 inclusive of all errors of form. (See also Clause 2 of Appendix B.) BSI BS*LLO4 57 Lb24bb9 0549339 T91 B.S. 1104 : 1957 TABLE 12 TOLERANCES FOR GO AND NOT GO SCREW THREAD AND PLAIN GAUGES. 11213, 4 151 6 . . . . . . . . - . , Simple eeaive diameter I ! oi screw plug ! on half 1- per I minus on ring
35、 rnd caiper : (+) and minor ingle 0 diamclers of thread screw rim aud ! cdipen (-1 I classes) i 4G and 56 Tolerances I Tolrrrncn on . . .j maior diameter I Tolerance Threidr i Plus on plug gauges,. (all inch uaugn Classes ZG 3G. (all clarrer _. . Tolcrmrci on in. in. minutes 16 0000 5 0.001 10 14 0.
36、000 5 0.001 10 12 O*OOO 6 0*001 10 10 0.000 6 0,002 10 8 0.000 1 0402 8 in. 0.000 3 0.000 4 0.000 4 0.000 4 0.000 5 - _. _-I_ - - Cliss 213 CIwe, 3G. I 4G and SC 6 0.000 9 o O00 I o 002 8 O O00 6 5 00010 O O00 8 0.002 8 O000 7 4 o 001 1 o O00 8 o 002 8 o O00 8 3 0.001 3 o O00 8 0.002 6 o O01 o 2 o 0
37、01 5 0.001 o o 002 6 o O01 2 - NOTE 1. The tolerances for pitch and angle of Acme screw thread gauges are inde- pendent of and additional to those given for the simple effcctive diameter. NOTE 2. Pitch and angle errors have the effect of increasing the eective diameter ofa plug gauge and decreasing
38、the effective diameter of a ring gauge. NOTE 3. For tolerances on pitch see Clause 17 of Section: TWO . 29). GAUGE LIMITS FOR THE STANDARD SERIES OF G&“. PURPOSE ACME THREADS 18. The limits and tolerances for gauges for the Standard Series of general purpose Acme threads are set out in full in Tables 13 to 17. BSI BSULLO4 57 1624669 0549340 703 m B.S. 1104 : 1957
