1、INTERNATIONAL STANDARD ISO 28574973/AMENDMENT 2 Pubiished 1986-09-15 INTERNATIONAL ORGANIZATION FOR STANDARDRATION. MEXYHAPOHAR OPrAHM3AMFi l-l0 CTAHflAPTlrl3AMlbORGANISATION INTERNATIONALE DE NORMALISATION Ground thread taps for ISO metric threads of tolerantes 4H to 8H and 46 to 6G coarse and fine
2、 pitches - Manufactured tolerantes on the threaded Portion AMENDMENT 2 Tarauds & fifets rectitk pour filetages mhtriques fS0 de tolbance 4H a 8H et 4G a 6G & pas gros et a pas fins - Tolhrances dexbcution de Ia pafiie tail#e AMENDEMENT 2 1 Amendment 2 to ISO 2857-1973 was prepared by Technicai Commi
3、ttee ISO/TC 29, Sma/ tools. Page 6 Deiete sub-ciause 4.5 and Substitute the foiiowing : 4.5 Tolerante on pitch The iimits of toierance on the pitch shaii be as shown in tabie 4, which also Shows the iength over which the measurement shail be made, expressed in number of pitches. Table 4 - Tolerante
4、on pitch t Pitch mm L 0,25 0,3 0,35 0,4 0,45 0,5 0,6 0,7 0,75 03 1 1,25 1,5 1,75 2 2,5 3 3,5 4 4,5 5 5,5 w 6 r - gi Measuring length Limits of in number of tolerante of pitches IJm 12 =f-8 9 L8 7 f8 f9 f 10 * 12 f 13 i 14 4 15 zk 16 f 17 f 18 UDC621.993 Ref. No. ISO 2857,1973/A2-1986 (E) Descriptors
5、 : tools, cutting tools, taps, screw threads, dimensional tolerantes. International Organkation for Standardkation, 1986 0 Printed in Switzerland Price group A ISO 285701973/A2-1986 (EI NOTE - The tolerante on pitch is based on the diametral equivalent of the pitch error, so that, in general, it sha
6、ll not exceed IO % of the 5H nut thread pitch diameter tolerante. The measuring length is based on seven pitches which falls within the “normal” length of thread engagement as detailed in ISO 965/1. However, for pitches finer than 1,5 mm, the measuring length has been increased to approximately 50 %
7、 of the Standard tap thread length to bring it within the scope of practical measurement. Page 7 Ciause 6 Last iine of the tabie, deiete “Cumulative pitch error TP over any number of threads” and insert “Tolerante on pitch” ?ages 8, 70 and 12 Annexes A and B Deiete three times : “Cumulative pitch error TP over any number of threads This error is fixed at + 0,05 % of the considered measuring iength with a minimum of Zr 0,008 mm.” and insert three times : “Tolerante on pitch See 4.5.”
