JIS B 7420 is a standard for torque wrenches, which are used to apply a specific amount of torque to a fastener or a bolt. The standard covers the calibration and adjustment of torque wrenches, ensuring that they are accurate and reliable.
It defines the "Go" and "No-Go" gauging principles. The "Go" gauge must fit the workpiece to ensure it doesn't exceed the maximum material limit, while the "No-Go" gauge must not fit to ensure the minimum material limit isn't breached .
: Specifically applies to tolerances IT6 to IT16 as defined in JIS B 0401 .
To ensure durability and usability, JIS B 7420 mandates specific design features:
If you need to know the specific tolerance calculation for a 20mm H7 hole based on this standard, I can help you find that. JIS B 7420 - 1997-03-31 - DIN Media