1、INTERNATIONAL STANDARD IS0 2857-19731AMENDMENT 1 Published 1984-07-15 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION- MEXAYHAPOflHAfl OPTAHM3ALblfl IlO CTAHAAPTM3ALlMM.ORGANISATlON INTERNATIONALE DE NORMALlSATlON Ground thread taps for IS0 Metric threads of tolerance 4H to 8H and 4G to 6G coarse and
2、 fine pitches - Manufacturing tolerances on the threaded portion AMENDMENT 1 Amendment 1 to international Standard IS0 2857-1973 was developed by Technical Committee lSO/TC 29, Small tools, and was circulated to the member bodies in January 1983. It has been approved by the member bodies of the foll
3、owing countries: Australia Hungary Austria India Belgium Italy China Japan Czechoslovakia Poland Germany, F. R. Romania South Africa, Rep. of Sweden Switzerland United Kingdom USSR The member bodies of the following countries expressed disapproval of the document on technical grounds: France USA UDC
4、 621.993 Ref. No. IS0 2857-1973/Al-1984 (E) , 2 Q) Descriptors : tools, cutting tools, taps, screw threads, dimensional tolerances. - 0 International Organization for Standardization, 1984 Printed in Switzerland Price based on 3 pages IS0 28571973/Al-1984 (E) Delete clause 4.4 and substitute: 4.4 To
5、lerances on the half-angle a/2 of thread The values for tolerances on the half-angle a/2 are based on the pitch of the thread and shall be in accordance with the values of table 3. Table 3 - Tolerances on the half-angle a/2 Pitch Tolerance on a/2 02 0,25 zk 70 0,3 0,35 * 50 Ot4 0,45 Or5 AI 35 0,6 01
6、7 0,75 z!I 30 W3 1 I,25 + 25 L5 I,75 2 23 * 20 3 3,5 4 4,5 5 III 15 5,5 6 NOTE - For a given pitch, the half-angle tolerance a/2 has been calculated so that the equivalent error on the virtual pitch diameter does not exceed a stated proportion of the pitch diameter tolerance To2 for the correspondin
7、g class 5 nut thread. The stated proportion is 8 %, except for pitches finer than 0,4 mm where it is 10 %. The calculated values have been rounded off to the nearest 5 to bring them within the scope of practical measurement. 2 IS0 285701973/A%1984 (E) Page 7 Clause 6 Delete the line before the last
8、in the left-hand column and substitute: “Tolerance on the half-angle of pitch (a/2)“. Page 9 Annex A In the table, replace the column “Tolerance on a and a/2” by the following: I Designation nomUinal / rFr I - M 1 I -_- - - - - - - - - i - - - - - - - - 1 -_- 1 - 1 - - - m-v I - ai - - - - - - 1 - -
9、 -m-v - - rl - If 50 zk 35 AI 25 ;:2 19 15 I,8 2 22 2,5 3 3,5 4 4,5 5 6 I t- E l-+-l E-l _+ 20 III 15 3 IS0 2857-1973/Al-1984 (E) Page 77 Annex B In the table, replace the column “Tolerance on a and a/Z” by the following: Class of taps Thread d Pitch Designation nomina, P M 1 x 0,2 1 M I,1 x 0,2 1 M
10、 1,2x0,2 I,2 M 1,4 x 0,2 I,4 02 M I,6 x 0,2 I,6 M I,8 x 0,2 I,8 M 2 x 0,25 2 M 2,2 x 0,25 2,2 0,25 M 2,5 x 0,35 2,5 M 3 x 0,35 3 0,35 M 3,5 x 0,35 3,5 M 4 x 0,5 4 M 4,5 x 0,5 4,5 M 5 x 0,5 5 0,5 M 5,5 x 0,5 5,5 M 6 x 0,75 6 - M 7 x 0,75 7 0,75 - M8 xl 8 M9 xl 9 1 Ml0 xl M 10 x 1,25 10 M 12 x 1,25 I,
11、25 12 - M 12 x I,5 1,5 Ml4 x1,25 VI 14 x I,5 . 14 I,25 _ VI 15 x I,5 15 VI 16 x I,5 16 I,5 VI 17 x I,5 17 VI18 x1,5 VI18 x2 I8 2 VI20 x1,5 I,5 M20 x2 2o 2 M22 x1,5 I,5 M22 x2 I22 2 M24 x1,5 24 I,5 VI24 x2 2 VI25 x1,5 VI25 x2 25 I,5 2 VI27 x1,5 115 - - VI27 x2 . 27 2 VI28 x1,5 I,5 VI28 x2 .28 2- - M
12、30 x I,5 vI3Ox2 30 2- I- -I Toter. or CYl2 -I I!z 70 _-_-_-_- - -_- - -I -_-_-_- - - _- _-_-_- -I I I!I 50 _-_-_- I -P-q _-_-_- f- 35 -p-p _-_- I I!z 30 _-_-_- _-_- -I -_-_- 1 -_- _- I _-_- -.- - 31 25 -P-P - -_-_- _- It 20 _-_- rt 25 _-_-_- I!I 20 _- 3 25 _- & 20 _-_-_-_- 31 25 _-_- + 20 _-_- IL 25 _- - -_- - Ik 20 _-_- I!I 25 _-_ -_-_- -_- - f 20 _-_- - 31 25 _ -_.- ._._. - -. -_- -_- - It 20 _-_-.-_ -.- ?I 25 _ _._ - _-_ - _-_ - - - + 20 n nominal 1 I, 12 9 116 M 2 22 2,5 3 315 4 4,5 5 5,5 6 7 8 9 IO 12 14 15 16 17 18 20 22 24 25 27 28 30 32 4
