Jis B 7420 Pdf May 2026

JIS B 7420:1997

is the primary Japanese Industrial Standard for Plain Limit Gauges . It provides the technical specifications and guidelines for gauges used to inspect holes and shafts for dimensional accuracy. ## Core Specifications

Typically every 5–10 years. The last major revision was 2017. Always check the JSA website for new editions. jis b 7420 pdf

1. Interchangeability: It ensures that a dial gauge from Manufacturer A fits standard holders and has similar performance characteristics to one from Manufacturer B.
2. Calibration: It provides the baseline values used during calibration. When a gauge is calibrated, it is checked against the tolerance tables defined in JIS B 7420.
3. Trust: A dial gauge marked "JIS B 7420 Compliant" guarantees a specific level of build quality and measurement accuracy.

Kaito was working on a prototype for a high-speed rail bearing. The tolerance was so tight it felt more like a suggestion of physics than a reality of manufacturing. He picked up the shaft, wiped it with a lint-free cloth, and reached for the ring gauge. JIS B 7420:1997 is the primary Japanese Industrial

• Cast iron plates: Require aging stress relief to prevent warping.
• Granite plates: Made from dense, fine-grained stone (often quartz diorite or basalt). The standard specifies hardness and water absorption limits.
• Steel plates: Less common, but covered for specific industrial applications.

Wear Limits

: Provides explicit values for the permissible wear of the gauge before it must be retired or recalibrated. ## Review & Availability Interchangeability: It ensures that a dial gauge from

manufacturers

Find who supply gauges compliant with this standard. Explain the specific tolerance tables for IT6 or IT7.