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
The standard focuses on "GO" and "NOT GO" gauging practices to ensure parts meet tolerance requirements without requiring expensive measurement equipment.
Dimensional Range: Applies to workpieces not exceeding 500 mm.
Tolerance Grades: Specifically covers grades IT6 to IT16 as defined in JIS B 0401.
Gauge Types: Includes specifications for plain plug gauges, plain ring gauges, and gap gauges (snap gauges).
International Alignment: It is technically based on ISO/DIS 1938-1, though it includes specific Japanese additions for measuring methods and trade disputes. ## Key Inspection Principles
According to the JIS B 7420 summary on PhysicsNorm, the standard utilizes a simple pass/fail system:
GO Gauge: Represents the maximum material limit (largest shaft or smallest hole). It must pass through or over the workpiece freely.
NOT GO Gauge: Represents the least material limit. It must not enter or pass over the workpiece.
Wear Limits: Provides explicit values for the permissible wear of the gauge before it must be retired or recalibrated. ## Review & Availability
Current Status: The 1997 version remains the active standard as of early 2026. jis b 7420 pdf
Document Length: Approximately 52 pages of technical data and annexes. Where to find it:
Official copies are available through the Japanese Standards Association (JSA).
Digital PDF downloads can be purchased from global providers like DIN Media or Intertek Inform.
🎯 Key Takeaway: Use this standard if you are manufacturing precision mechanical parts for the Japanese market that require high-volume inspection using limit gauging. If you'd like, I can:
Find manufacturers who supply gauges compliant with this standard. Explain the specific tolerance tables for IT6 or IT7.
Compare this to the ISO 1938 standard to see if your current tools already comply.
Let me know what specific part of the standard you need to apply! JIS B 7420:1997 Plain limit gauges - Intertek Inform
JIS B 7420:1997 is a critical Japanese Industrial Standard titled "Plain Limit Gauges."
It serves as the primary technical blueprint for manufacturing and inspecting dimensional accuracy in holes and shafts. Intertek Inform Core Function & Scope
This standard specifies the design, dimensions, and tolerances for plain limit gauges and reference disks. Intertek Inform Target Workpieces : Dimensional inspection of holes and shafts up to Tolerance Grades : Applies to tolerance grades IT6 to IT16 as defined in JIS B 0401. International Alignment : It is closely based on ISO/DIS 1938-1 JIS B 7420:1997 is the primary Japanese Industrial
, maintaining technical consistency with global standards for plain limit gauges. Intertek Inform Key Features of the PDF Standard
A typical "JIS B 7420 PDF" provides comprehensive technical tables and diagrams essential for quality control: 分析测试百科网 Gauge Classification : Defines the shapes and sizes of Wear Limits
: Specifies the permissible wear for gauges to ensure they remain accurate over repeated uses. Manufacturing Specs : Includes details on gauge blanks, handles, and materials. Terminology
: Establishes standard definitions for measuring instruments like ring gauges and plug gauges. 日本規格協会 JSA GROUP Webdesk Why It’s Essential for Manufacturers Precision Control
: It ensures that components like shafts and bores fit perfectly by using standardized "limit" testing rather than variable manual measurements. Cost Efficiency
: By standardizing the gauges used across industries, it reduces custom tooling costs and simplifies third-party inspections. Interchangeability
: Parts manufactured to JIS B 7420 specs are guaranteed to be interchangeable, which is vital for global supply chains. NormSplash Accessing the Standard
You can find the official document through these authoritative platforms: JIS B 0251:2008 - NormSplash
JIS B 7420 standard, titled "Plain Limit Gauges," is a foundational Japanese Industrial Standard used in manufacturing to ensure dimensional accuracy. It defines the design, tolerances, and inspection criteria for "Go" and "No-Go" gauges used to check holes and shafts. Overview of JIS B 7420 Revised in 1997, this standard is technically aligned with ISO/DIS 1938-1
but includes specific Japanese measuring methods and additional guidance for trade disputes. It applies to workpieces with dimensions up to and tolerance grades from IT6 to IT16 Intertek Inform Core Metrological Concepts Title and scope: defines the parts, components, or
The standard revolves around the principle of limit gauging, which determines if a part's actual size falls within its specified limits without measuring an exact numerical value. : Designed to check the Maximum Material Limit (MML)
—the largest possible shaft or the smallest possible hole. A "Go" gauge must fit or pass through the part. NOT GO Gauges : Designed to check the Least Material Limit (LML)
—the smallest shaft or the largest hole. These should not fit or pass through the part. Wear Allowance
: JIS B 7420 accounts for the gradual wear of "Go" gauges by allowing a specific portion of the tolerance zone for "permissible wear," ensuring the gauge remains valid over time. NormSplash Gauge Types and Design
The standard specifies various physical forms for these inspection tools: Plug Gauges : Used for internal diameters (holes). Ring and Snap Gauges : Used for external diameters (shafts). Reference Disks : Used specifically for calibrating or checking gap gauges. Intertek Inform Manufacturing Significance
JIS B 7420 is essential for high-volume production because it allows for rapid "Pass/Fail" inspection without expensive digital measuring equipment. It provides a standardized framework that prevents disputes between manufacturers and purchasers by defining how to handle components that are very close to their tolerance limits. NormSplash
For further technical details, you can find official versions of the JIS B 7420:1997 at platforms like Intertek Inform for a specific IT grade or shaft size? JIS-B-7420-1997-1.pdf - PhysicsNorm
Use the standard’s recommendations to set calendar reminders for surface plate re-calibration every 12–24 months.
They require a surface plate (typically granite) that meets the flatness tolerance for Grade 0 as defined in Table 2 of the standard. You will need a calibration certificate referencing that specific grade and standard.
The standard also addresses how the plate must be supported (e.g., three-point leveling systems) to prevent deflection under load.