JB/T 8825.3-1998 The dimensional accuracy and geometric tolerances of this standard are formulated with reference to the British Standard BS 949.2-1979 "Specifications for Taps (Part 2) Taps with Unified Threads". The rest of the standard is formulated with reference to GB/T 968-1994 "Tolerances for Tap Threads". This standard specifies the technical requirements for the dimensions, materials and hardness, appearance and surface roughness, marking and packaging of Whitworth thread taps and Whitworth nut taps. This standard is applicable to taps and nut taps produced in accordance with JB/T 8825.1 and JB/T 8825.4. This standard was first issued on December 29, 1998. JB/T 8825.3-1998 Technical conditions for Whitworth thread taps JB/T8825.3-1998 standard download decompression password: www.bzxz.net

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Machinery Industry Standard of the People's Republic of China
JB/T8825.3—1998
Whitworth Thread Taps
Technical Conditions
Technical Specification for Whitworth Threads Taps1998-12-29 Issued
National Bureau of Machinery Industry
1999-07-01 Implementation
JB/T8825.3—1998
The dimensional tolerance and geometric tolerance of this standard are formulated in accordance with British Standard BS949.2—1979 "Thread Specification [Part 2] Unified Thread Dimensions". The rest of the standard is formulated in accordance with GB/T969—1994 "Technical Specification for Taps". This standard was first issued on December 29, 1998. The National Knife Standardization Technical Committee proposed and coordinated this standard. The main drafting unit of this standard is Shanghai Cutting Tool Factory. 1 Scope
Machinery Industry Standard of the People's Republic of China
Whitworth Thread Taps
Technical speclfication for whitworth threads tapsJB/T8825.3—t998
This standard specifies the technical requirements for the size, material and strength, appearance and surface roughness, marking and color of Whitworth thread taps (hereinafter referred to as taps) and Whitworth thread master taps (hereinafter referred to as master taps). This standard applies to the thread chains and nut threads produced in accordance with B/8825.1 and J/18225.4. 2 Reference standards
The provisions contained in the following standards constitute the auxiliary texts of this standard by being cited in the standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and the parties using this standard should explore the possibility of adopting the latest versions of the following standards. JB/8825.1-1998 B/T8825.2-1998 Whitworth tap thread tolerance JB/T8825.4-1998 Whitworth tap thread pliers 3 dimensions
thread type and size limit deviation of taps and nuts shall be in accordance with the provisions of JB/T8825.2 3.1
3.2 Cutting and cutting the thread chain, check the middle diameter at the calibration point (when the calibration part of the tap is less than 4 teeth from the front, the middle diameter is checked at 4 teeth from the front end), and the nut key is checked at the midpoint of the cutting part, 1~2 teeth away from the calibration part. The tolerances of the shank diameter and square head of the tap and nut are given in Table 1. 3. 3
The diameter of the shaft
The symmetry of the square head of the threaded chain to the axis of the shank shall not exceed 1/3 of its size tolerance. The tolerance of the total length L of the threaded chain and the tolerance of the threaded length are given in Table 2. Table 2
3/16~3/8
National Pump Industry Standard 1998-12-29 Approved 716-7/8
Square head length
1999-07-0 Implementation
JA/T$825.3—1998
3.6 Check the radial runout of the thread and nut thread tough cutting part, calibration part and orange part before pre-pointing. The limits are given in the table. Table 3
3/4~1%
3. For taps and nuts, the threaded part of the tap should have a specific dimension.
Return to the selected part
3.B The thread profile of the ground thread with a nominal diameter greater than 7.938mm shall be subjected to grinding: when the user allows, the thread profile of the threaded thread may not be ground. 4 Material and Dimensions
Difficulty
Slightly Threaded
Both radial surfaces
4.1 The threaded part of the tap shall be made of W6Mo5Cr4V2 or other high-speed steel (code HSS) with equivalent performance, or it may be made of high-speed steel (code HSS-E). The threaded part of the tap shall be made of 9SiCr, T12A or other grades of tool steel with equivalent performance, Russian tool steel, or it may be made of high-speed steel. The welding handles are made of 45 steel or other steels with equivalent performance. 4.2 The minimum allowable hardness of the threaded part of the tap and nut is given in Table 4. Table 4
1/8-7/32
Alloy tool steel, tool pin
60 HRC www.bzxz.net
G! HRC
High-strength steel
4.3 The hardness of the two times the square head length of the broken shank end of the tap and nut handle should not be less than 30HRC. 5 Appearance and surface roughness
High-strength steel
3. The tap and nut tap surface shall not have defects such as plugging, threading, rust and grinding burns that affect the performance. 5.2 The connection between the front of the tap and the groove of the tap nut should be smooth. 5.3 The upper limit of the surface roughness of the tap and nut thread is given in Table 5. Item
Screw thread
JB/T8825.3—1998
Compensated wire
Previous; Nominal diameter 31.730rmm of the anti-cut screw thread hard handle that roughness - not specified. 6 Marking and packaging 6.1 The taps shall be marked with: a) Manufacturer’s trademark or seller’s trademark: b) Screw code: 3) Thread tolerance band code (cut wire is not allowed to be marked): 4) Dimensional mark of unequal diameter grouped wires (1 ring for the first thread, 2 rings for the second thread or sequence number 1, +/- 5) Material code (HSS for those made of high-performance high-strength steel: HSS-E for those made of carbon-degraded tool steel and alloy tool steel is not allowed to be marked). Note: Wire with a nominal point diameter of 6.350mm is allowed to be marked with only the tolerance band code and the effect code. 6.2 The packaging shall be marked with: 8) Manufacturing! a) Name, trademark and address of the manufacturer or distributor: b) Wire marking:
c) Material brand and code:
d) Number of pieces;
) Year and month of manufacture.
5.3 Packaging
Wires must be treated with rust-proofing before packaging. The packaging must be secure and prevent damage during transportation:
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