GB/T 3934-2025Specification of gauges for general purpose screw threads (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents". Drafting. This document replaces GB/T 3934-2003 "Technical Conditions for General Thread Gauges". Compared with GB/T 3934-2003, the only changes are in the structural design. Aside from integration and editorial changes, the main technical changes are as follows:

a) The scope of this document has been changed (see Chapter 1, Chapter 1 of the.2003 edition);

b) The terms and definitions have been changed (see Chapter 3, Chapter 3 of the.2003 edition);

c) The descriptions of the symbols have been changed (see Chapter 4, Chapter 5 in the.2003 edition);

d) The usage rules have been changed (see Chapter 5, Chapter 4 of the.2003 edition);

e) Increased requirements for functionality, features, and controls (see Chapter 5);

f) The Vickers hardness value of the measuring face of the thread gauge measuring head has been changed (see 8.4.1,.2003 edition of 8.4.1);

g) The detection parameters and instrument descriptions have been changed (see Table 13, Table 13 in the.2003 edition);

h) The inspection parameters, inspection methods, inspection locations, and inspection instruments for thread ring gauges have been added (see Table 14);

i) The hardness values of the measuring surfaces of the smooth limit gauges have been changed (see Appendix A, Appendix A of the.2003 edition). Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents. This document was proposed by the China Machinery Industry Federation. This document is under the jurisdiction of the National Technical Committee on Standardization of Measuring Instruments and Gauges (SAC/TC132). This document was drafted by: Chengdu Xinchengliang Tools Co., Ltd., Chengdu Tool Research Institute Co., Ltd., and Hengfeng Tools Co., Ltd. The main drafters of this document are. Xu Yan, Zhao Panzong, Xu Gang, He Yixian, and Yang Minli. This document was first published in 1983, revised for the first time in.2003, and this is the second revision. Technical specifications for ordinary thread gauges

1 Scope

GB/T 3934-2025 is the Chinese national standard covering the go and no-go gauges for metric threads - the gauge tolerances and the wear allowance, the calibration, and the rules on when a gauge is worn past use, which is what keeps a thread interchangeable between two factories. Issued on 31 October 2025, it has been in force since 1 May 2026, replacing GB/T 3934-2003.

This document specifies the symbols and descriptions, classifications, tolerances, requirements, inspection and acceptance of general thread gauges (hereinafter referred to as "thread gauges"). Logos and packaging. This document applies to thread gauges with a thread angle of 60°, a nominal diameter of 1mm to 300mm, and a pitch of 0.2mm to 8mm. Applicable to the inspection of ordinary threads specified in GB/T 192, GB/T 193, GB/T 196 and GB/T 197.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included. For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies. This document.

GB/T 197 Tolerances for Standard Threads

GB/T 14791 Thread Terminology

3 Terms and Definitions

The terms and definitions defined in GB/T 14791 apply to this document.

4.Symbols and Explanations The symbols and descriptions listed in Table 1 apply to this document. Table