JB/T 9988.2-1999 This standard is a revision of ZB J41 002.2-87 "Thread tolerances for high-precision trapezoidal thread broaching taps". During the revision, only editorial changes were made in accordance with relevant regulations, and the technical content remained unchanged. This standard is part of the JB/T 9988 "High-precision trapezoidal thread broaching taps" series of standards. This series of standards includes the following three parts: JB/T 9988.1: Types and dimensions JB/T 9988.2: Thread tolerances JB/T 9988.3: Technical conditions This standard specifies the thread profile of high-precision trapezoidal thread broaching taps and the limit deviations of their basic dimensions, and gives several explanations on the tolerances of high-precision trapezoidal thread broaching taps in Appendix A (Appendix to the standard). This standard applies to high-precision trapezoidal thread broaching taps (hereinafter referred to as taps) used for machining trapezoidal threads (according to JB/T 2886-1992 "Technical Conditions for Trapezoidal Screws and Nuts for Machine Tools", Grades 7, 8, and 9 are not matched as nuts). The threads of taps are divided into Grade 1 and Grade 2. This standard was first published on the date of year. JB/T 9988.2-1999 High-precision trapezoidal thread broaching taps Part 2: Thread tolerances JB/T9988.2-1999 Standard download decompression password: www.bzxz.net

JCs 25.100.50
Machinery Industry Standard of the People's Republic of China
JB/T9988.19988.3-1999
High Precision Trapezoidal Thread Broaching Taps
1999-05-20 Issued
National Machinery Industry Bureau
2000-01-01 Implementation
JB/T9988.2—1999
This standard is a revision of ZBJ41002.287 High Precision Trapezoidal Thread Drawing End Tolerances. The revision has been edited and the technical content has been changed according to relevant regulations. This standard is part of JBT9988 "High Precision Trapezoidal Thread Drawing System Standard". This series of standards includes the following:
J9988.1—1999
High-precision trapezoidal thread broaching taps Part 1: Types and dimensions JE9988.2-1999 High-precision trapezoidal thread broaching wire Part 2: Thread tolerance JB/T9988.31999 High-precision trapezoidal thread broaching wire Part 3: Technical conditions This standard will replace ZBJ41002.2—8 from the date of implementation. Appendix A of this standard is the appendix of the standard.
This standard is proposed and managed by the National Technical Committee for Tool Standardization, and the responsible unit for the reform of this standard is the Tool Research Institute under the Ministry of Development and Reform. The main drafters of this standard are: Yao Tigui, Li Fulu, Zhang Yanguang, Wang Yisu, Tao Weiwei, Jiang Wenyun, Xia Yu. 1 Scope
Machinery Industry Standard of the People's Republic of China
High-precision trapezoidal thread broaching taps
Part 2: Thread tolerances
JE/T9988.2-19
Replacement J410022—87
This standard specifies the requirements for high-precision trapezoidal thread broaching taps The thread type of the wire cutting chain sets the limit deviation of its basic size, and gives some details about the tolerance of high-precision trapezoidal thread cutting key in Appendix 4 (Standard Appendix). This standard is applicable to the thread type of high-precision trapezoidal thread cutting chain (hereinafter referred to as wire cutting chain) used for machining trapezoidal threads (according to JBT2886-1992 Machine Tool Trapezoidal Thread Screw and Nut Technical Conditions" 78, 9 Grades Not Matched as Nuts) and is divided into: Grade 1 and Grade 2. 2 Reference Standards
The provisions contained in the following standards become the provisions of this standard by reference in this standard. When this standard is published, the versions shown are not all valid. All standards may be revised, and the application of the following standards should consider the technical performance of the latest versions. B28-1 Machine Tool Trapezoidal Thread Screw and Nut Technical Conditions 3 Thread Type and Size Limit Deviation
3.1 The thread type of the tap is shown in Figure 1, and the size limit deviation is shown in Table 1. Self-
Edition card public belt
Public welfare parts
Basic model
Approved by the State Machinery Industry Bureau on 1999-05-206
2000-01-01 Real department
Public selection path
> 11.222.4
>22.4-45.0
> 45 -00.n
Large light d
lower deviation! Upper deviation
JB/T9988.7-1909
Lower deviation
1: Deviation
Lower deviation
Upper deviation
Lower and upper deviation
Distance between butterflies
Tooth profile half angle
Tooth effect
Grade 1, 2
, Grade 2
± 10°
【The minor diameter of each level of wire is smaller than the minimum diameter of the processed nut, that is, the minor diameter of the wire teeth should not exceed the minimum diameter of the nut. The main dimensions of the major diameter, middle diameter, and minor diameter are respectively the basic dimensions of the trapezoidal internal thread effect D, D, and D. alternate. i±tor
A1 Tap middle diameter
JB.T9988.21999
Appendix A
(Standard Appendix)
Some explanations on tap thread tolerancebzxZ.net
AI.1 Tap middle diameter tolerance, lower deviation ei, upper deviation es values ​​are calculated as a percentage of (non-matching female middle diameter tolerance T in JB/T2886). Table A1 gives Table A1
Conversion thread version
Pure middle diameter lower deviation
Whose middle diameter tolerance
Thread middle diameter tolerance
A1.2 The relationship between the middle diameter tolerance of the tap specified in this standard and the internal thread middle diameter tolerance band is shown in A1. 28
The basic tooth type thread diameter (medium and light) (horsepower pipe
A1.3) and the processing range suitable for each level of taps are given in Table A2. Table A2
The corresponding thread diameter of thread type
8 and 9
Due to many factors affecting the economic dimensions, such as the properties of the drawn material, the accuracy of the machine tool and tooling, the cutting speed, the type of thread, etc. Therefore, the applicable range of the thread listed in Table A2 can only be used as a reference when selecting the thread. Use the appropriate tap within the range listed in this standard based on the conditions of 1 and the production experience and tests.
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