JB/T 9995-1999 This standard is a revision of ZB J41 012-89 "Thread tolerances of 55° cylindrical pipe threads taps". During the revision, only editorial changes were made according to relevant regulations, and the technical content was not changed. The original standard non-equivalently adopted the international standard ISO 5969-1979 "Thread tolerances of ground thread taps for pipe threads G series and Rp series". This standard specifies the limit deviations of the thread profile and basic dimensions of 55° cylindrical pipe threads, and gives some explanations on the thread tolerances of 55° cylindrical pipe threads taps in Appendix A (suggestive appendix). This standard is applicable to taps for machining 55° cylindrical pipe threads. This standard is divided into three types of tap thread tolerances: G series, GD series and Rp series. The thread tolerances of G series and GD series taps are applicable to the processing of pipe threads without thread seals (according to GB/T 7307-1987 "Pipe threads without thread seals"), and the thread tolerances of Rp series taps are applicable to the processing of pipe threads with thread seals (according to GB/T 7306-1987 "Pipe threads with thread seals"). This standard was first issued on . JB/T 9995-1999 Thread tolerances of 55° cylindrical pipe threads JB/T9995-1999 Standard download decompression password: www.bzxz.net

ICS25.100.50
Machinery Industry Standard of the People's Republic of China
JB/T9995-1999
Thread Tolerance of 55° Cylindrical Pipe Thread Tap
1999-05-20 Release
National Bureau of Machinery Industry
2000-01-01 Implementation
JBRF9995-1999
This standard is for the revision of the thread tolerance of ZBJ41012-8V&55\Toilet Pipe Thread. During the revision, only the relevant provisions are followed for the revision. The technical content is technical. According to the standard, the international standard [S05969-1979 is adopted. The thread tolerance of G series and R series pipes needs to be replaced by this standard from the date of implementation. The items in this standard are minor additions. This standard is proposed and managed by the Standardization Technical Committee of the city. The responsible unit for the standard is the Institute of Technology. The main authors are Jiang Xiuguan, Yin Jia, Hu Youbao, Xue Xueguang, Scope of the Standard: Mechanical Industry Standard of the People's Republic of China: 55° cylindrical pipe thread tap thread tolerances. IR/T 0995-T999: 1984-12-89. This standard specifies the limit deviation of the thread tooth form and basic size of 55° cylindrical pipe thread. In the Appendix A (Reminder Appendix), some instructions on the thread tolerance of 55° cylindrical pipe thread are given. This standard is applicable to the processing of 55° cylindrical pipe thread. This standard is divided into three types of thread tolerances: G series, G-series and RF series. The thread tolerances of the 3.L series are applicable to pipe threads with non-thread sealing function (refer to GR/T7.307-1987 for pipe threads with non-thread sealing function. The thread tolerances at 3R are applicable to pipe threads with thread sealing function! According to H7306-1987 for pipe threads with thread sealing function)
2 References
The provisions contained in the following standards are the provisions of this standard through reference in this standard. When this standard is published, the revisions shown are effective. All standards contain revisions. Parties using this standard should consider the possibility of using the latest version of the following standards: GB/T9681994
Thread tolerances
GB/T73061987 Thread grades for pipes with threaded seals GR/T7307-1987 Thread types and dimensional tolerances for pipes without threaded seals
3.1 The thread types of G series and D series wire chains are shown in Figure 1, and the dimensional tolerances are shown in Tables 1 and 2. a) Standard thread tooth form () large light (D,)-minor diameter (D,)-middle diameter (a)-middle diameter tolerance (T-minor diameter tolerance approved by the State Machinery Industry on May 20, 1999) b) Standard thread tooth form JS large light lower than the lower middle diameter (cs-middle diameter adjustment difference) H-original triangle two degrees (P-pitch) implemented on January 1, 2000 Basic size: 75.184 JE/I9995-1999 29 039 36 418
Basic size for
Exploding fat and dense silk
Tooth type and
Basic good size
47 B03
151130
JBT9995-1999
Basic size
136951
+47 : 94
Taichi City
20 587
34 939
：62.752
Screw deviation
JB/r999S—1999
3.2 Long P series of wire chain thread type as shown in Figure 2, size limit deviation see Table 30.137329
Nut thread type
b) Wire auxiliary thread type
Basic size
75 184
87 884
1 White/ten 9995—1999
Basic size
15 o06
109,--74
Hepburn sizebzxZ.net
Thread pitch confirmation
± 25'
A1 Wire thread middle diameter
JR/T9995-1999
Appendix A
(Reminder Appendix]
About the description of the thread tolerance of the wire chain
A"! The thread middle diameter tolerance T, lower tolerance ct, and lower tolerance e values ​​are calculated as a percentage of the (all levels of nut thread middle diameter tolerance T) given in Table 1,
Flower ladder series
G-pattern to
Labor standard thread middle diameter lower tolerance||tt ||The tolerance band of the thread diameter specified in this standard is relative to the tolerance band of the thread diameter as shown in the company AI.
A2 The thread diameter and the thread diameter of the basic tooth type (-) are determined by the manufacturer/self-determination. The upper and lower deviations JS are calculated by formula (A) and (A2) GD series
Rp series
JS= -0.3 t ..
Thread tooth type half angle and pitch
4 The deviation of the half angle and pitch of the thread type specified in the standard is determined by the Japanese T968 (A1)
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