For quality inspectors, manufacturing engineers, and gauge designers, accessing the full is essential for:
The standard was first established on March 1, 1964, and was last revised on March 20, 1997, into the current version, JIS B 7420:1997. This revision harmonized the Japanese standard with the international standard , "Inspection of plain workpieces – Part 1: Plain limit gauges," aligning Japanese practices with global norms.
The JIS B 7420 standard is not an isolated document. It was developed in direct alignment with the international standard , titled "Inspection of plain workpieces - Part 1: Plain limit gauges". In standardization terminology, the relationship is designated as MOD (Modified) . This means that while the JIS version is technically equivalent to the ISO draft, it includes additional or modified elements. jis b 7420 pdf
Before diving into the technical specifications of a , it helps to understand why limit gauges remain foundational in machine shops and assembly lines:
While the official sources are the safest bet, some third-party sites may host copies of the standard. It is critical to treat these with extreme caution. It was developed in direct alignment with the
To understand the standard, it's essential to know its key definitions:
Plain limit gauges for dimensions not exceeding 500 mm. Corresponding ISO: ISO/DIS 1938-1. Key Technical Requirements of JIS B 7420 Before diving into the technical specifications of a
| Gauge Name (English) | Gauge Name (Japanese) | Primary Function | | :--- | :--- | :--- | | | 限界プレーンゲージ (Genkai Purēn Gēji) | The overarching category for gauges used in dimensional inspection. | | Ring Gauge | 環ゲージ (Wa Gēji) | An outer ring gauge used to inspect the outer diameter (OD) of shafts or cylindrical parts. | | Plug Gauge | 栓ゲージ (Sen Gēji) | A cylindrical "plug" type gauge used to inspect the inner diameter (ID) of holes or bores. |
Utilize precise gauge tolerances for IT6–IT16 classes as defined in JIS B 0401.