JJF 1345-2012 in English

1 Scope

This specification is applicable to the calibration of symmetrical straight flank profile cylindrical thread gauge.

2 Normative References

The following documents are cited by this specification:

JJF 1071-2010 The Rules for Drafting National Calibration Specification
GB/T 3934-2003 Specification of Gauges for General Purpose Screw Threads
GB/T 14791-1993 Terms of Screw Threads
GB/T 27025 General Requirements for the Competence of Testing and Calibration Laboratories

For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms

See GB/T 3934-2003 and GB/T 14791-1993 for the terms of cylindrical threads.

4 General

Cylindrical thread gauge is measuring instrument for comprehensively inspecting dimension and boundary conditions of internal and external cylindrical thread elements and controlling the limiting dimension of cylindrical thread elements.

See Figure 1 for the elements that make up the cylindrical thread.



d2——pitch diameter; d——major diameter; d1——minor diameter; P——pitch;
α1, α2——flank angle; α——thread angle, α＝α1+α2

Note: The patterns and symbols in the figure are applicable to external thread.

The symbols for pitch diameter, major diameter and minor diameter of internal thread are expressed as D2, D and D1 respectively, and others are identical to that of external thread.

5 Metrological Characteristics

Foreword i
Introduction ii
1 Scope
2 Normative References
3 Terms
4 General
5 Metrological Characteristics
5.1 Metrological Characteristics and Symbols
5.2 Metrological Characteristics Calibration Combination
6 Calibration Conditions
6.1 Environmental Conditions
6.2 Standard Instruments and Other Equipment
7 Calibration Items and Methods
7.1 Calibration Item Combination
7.2 Calibration Methods
8 Expression of Calibration Results
9 Recalibration Time Interval
Annex A Calibration of Working Ring Gauges of Small Size and Those for General Purpose
Annex B Example for Assessment on Measurement Uncertainty of Pitch Diameter
Annex C Example for Pitch Diameter Calculation
Annex D Format of Calibration Record and Calibration Certificate Inside Page
Annex E List of Symbols Used in the Specification