What tool is generally used to calibrate a micrometer or check its accuracy?

What tool is generally used to calibrate a micrometer or check its accuracy?

• A. Gauge block
• B. Dial indicator
• C. Machinist scale
• D. Micrometer caliper

Answer: (A)

A precise reference standard called gauge blocks is used to calibrate a micrometer. Gauge blocks are manufactured to extremely tight tolerances and come with calibration traceability to national standards, giving a known, highly accurate length. To check the micrometer, you close the spindle onto a gauge block (or a stack of blocks) of a specific, precise length and compare the reading to that length. If the micrometer shows the correct length within its stated error across its range, it’s considered accurate. This method provides a stable, repeatable reference across measurements and accounts for the instrument’s operating range and temperature considerations. Other tools like a dial indicator or a machinist scale don’t provide a fixed, traceable length reference for calibration, and a micrometer caliper is another measuring instrument rather than a standard.

A precise reference standard called gauge blocks is used to calibrate a micrometer. Gauge blocks are manufactured to extremely tight tolerances and come with calibration traceability to national standards, giving a known, highly accurate length. To check the micrometer, you close the spindle onto a gauge block (or a stack of blocks) of a specific, precise length and compare the reading to that length. If the micrometer shows the correct length within its stated error across its range, it’s considered accurate. This method provides a stable, repeatable reference across measurements and accounts for the instrument’s operating range and temperature considerations. Other tools like a dial indicator or a machinist scale don’t provide a fixed, traceable length reference for calibration, and a micrometer caliper is another measuring instrument rather than a standard.