JIS B 7731 (Shore hardness test — Calibration of reference blocks)

JIS B 7731 · JIS standard

JIS B 7731 is the Japanese Industrial Standard for calibrating the Shore hardness reference blocks used to indirectly verify Shore hardness testing machines (durometers). Calibrated blocks are what let a durometer be checked and trusted. To calibrate Shore reference blocks or match them to your durometers, talk with our team.

What JIS B 7731 Covers

The standard defines how Shore hardness reference blocks are calibrated and certified across the relevant hardness range, so they can serve as the reference for checking Shore durometers used on rubber, elastomers, and plastics.

Why It Matters

Shore hardness is a quick, common check on elastomers and soft plastics, so a durometer that has drifted can misjudge material. Calibrated JIS B 7731 blocks keep those readings defensible.

Reading the Designation

Cited as JIS B 7731 with its edition year. Confirm the edition and the Shore scale (such as A or D) relevant to your work.

How Reference Blocks Are Used

Indirect verification with certified blocks is the practical check that keeps a durometer in tolerance:

Select reference blocks that bracket the hardness range you test.
Measure each block with the durometer under normal conditions.
Compare the readings against the certified block values and permitted tolerance.