JB/T 8825.2-1998 This standard is formulated with reference to the relevant parts of British Standard BS 949.2-1979 "Specification for Taps (Part 2) Taps with Unified Threads". The thread limit size deviation is in accordance with the relevant provisions of BS 949, and some incorrect dimensions have been modified. The half-angle deviation is formulated with reference to my country's national standard GB/T 968-1994 "Tolerances of Tap Threads". This standard specifies the limit deviations of thread profile and size of Whitworth thread taps. This standard is applicable to Whitworth thread taps. This standard was first issued on December 29, 1998. JB/T 8825.2-1998 Whitworth thread tap thread tolerance JB/T8825.2-1998 standard download decompression password: www.bzxz.net

ICS 25. 100. 50
Machinery Industry Standard of the People's Republic of China
JB/T 8825.2—1998
Whitworth Thread Taps
Thread Tolerance
Manufacturing tolerances on the threaded portion for whitworth threads tapsPublished on 1998-12-29
National Bureau of Machinery Industry
Implemented on 1999-07-01
JB/T8825.2--1998
This standard is formulated with reference to the relevant parts of British Standard BS949.2-1979 "Tap Specification (Part 2) Taps with Unified Threads". The limit deviation of thread size is in accordance with the relevant provisions of S949, and some incorrect dimensions have been modified. The half-angle deviation is formulated with reference to the national standard GB/T96B-1994 "Tap Thread Tolerance". This standard was first issued on December 29, 1998. Appendix A of this standard is a prompt appendix.
This standard was proposed and managed by the National Technical Committee for the Promotion of Tool Standards. The main drafting unit of this standard: Shanghai Cutting Tool Factory. 1 Scope
Mechanical Industry Standard of the People's Republic of China
Whitworth thread taps
Thread tolerances
Maaufacturiag tolerances on the threaded portion for whitworth threads taps This standard specifies the limit deviations of thread profile and size of Whitworth thread taps (hereinafter referred to as taps). This standard is not applicable to taps for machining Whitworth threads. Tap thread profile and size limit pad
JB/T 8825.2-1998
The thread profile of the tap is shown in Figure 1, and the size limit deviations are given in Tables 1 and 2 (the upper deviation of the tap major diameter, and the upper and lower deviations of the minor diameter are specified by the manufacturer). | |tt |
Guohao Machinery Industry Bureau approved Drawing 1 on 1998-12-29
Implemented on 1999-07-01
Nana Code
1/8-40BSw
3/16-24 BSW
1/4-20BSW
5/16-18ESW
3/8-16
7/6-14BSW
-1/2-12BSW
9/16-12BSW
5/8-11 BSW
1116-11 BSW
3/4-t0BSw
7/8-9 BSw
I-8BSw
1%-7 BSw
1%-7 BSW
%-6 BSW
1%-5 BSW
2-4 BSw
Major diameter d
Lower deviation「+
2nd grade grinding
3rd grade grinding
Lower deviation【+】
2nd grade grinding
3rd grade grinding
Upper deviation【】
2nd grade grinding
3rd grade grinding
Pitch tolerance for every 25.4mm
2nd grade, 3rd grade
Half angle deviation 4=
2nd grade, 3
±50°
±25″
±45°
JB/T 8825.2 -1998
Thread code
2y-4 Bsw
2 years old-BSW
2%-3y BsW
3-3YBsw
3%-3y BSW
3%-3yBsw
3% -3B3W
4-3BSW
Thread code
3/16-32BSF
7/32-28 BSF
1/4-26BSF
9/32-26BSF
Large diameter d
Lower adjustment difference +】
3rd grade grinding
Large diameter d
Lower deviation (+)
2nd grade grinding
3rd grade grinding
Table (finished)
Zhongjingshan
Lower deviation (+)
2nd grade grinding
Deviation (-)
2nd grade grinding
Zhongjingshan||tt ||Lower deviation (+)
2nd level grinding
3rd level grinding
3 short grinding
Upper deviation (+)
2nd level grinding
3rd level grinding
Sea 25.4mm upper screw roll
2nd level, 3rd level
Each 25.4mm upper burst distance deviation roll
2nd level, 3rd level
Half angle deviation 4
2nd level, 3
Half angle deviation 4
2nd level, 3
JB/T 8825-2 - 1998
Screw code
5/1622 8SF
3/8-20 BSF
7/16-18BSF
1/2-16 BSF
9/16-16 BSF
5/8-14BSF
11/16-1 4 BSF | | tt | | 3/4-12BSF | BSF
1%-7 BSP
2-7 BSF
Large diameter d
Lower energy difference (+))
2nd grade
3rd grade grinding
Table 2 (continued)
Middle diameter
Lower deviation (+)
2nd grade grinding
3rd grade grinding
Road 2
Pitch deviation per 25.4mm
2nd grade, 3rd grade
Half angle deviation 4
2. Grade, 3
±30°
JB/T 8825.2 -
Luo system code
2-6 BSF
2-6BSF
2%-6BSF
3Y-S BSF
3-4BSF
44%BSF
5.644 95.250|| tt||Large diameter a
Lower enough (+)
2 grinding
3 level grinding
Table 2 (Finish)
Medium diameter d
Lower deviation (+)
2nd grade paste
3rd grade
Upper deviation (+)
2 paper grinding
3 satin grinding
0.1480.218
Every 25.4mm upper pitch deviation
2nd grade, 3rd grade
Half angle deviation 4
2nd grade, 3wwW.bzxz.Net
JB/T 8825.2 -1998
JB/T 8825.2—1998
Appendix A
(Appendix to the standard)
Corresponding relationship between the tolerance zone of the middle diameter of the tap and the tolerance zone of the middle diameter of the internal thread A1 The corresponding relationship between the tolerance zone of the middle diameter of the tap and the tolerance zone of the middle diameter of the internal thread is shown in Figure A1. The medium-light tolerance of the internal thread is replaced by the medium-light tolerance of the internal thread.
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