Which of the following tools might be used to check a micrometer for accuracy?

Which of the following tools might be used to check a micrometer for accuracy?

• A. Dial test indicator
• B. Calipers
• C. Gauge block
• D. Feeler gauge

Answer: (C)

The main idea is using a precise length standard to verify a micrometer’s accuracy. Gauge blocks provide that reference because they are manufactured to tightly specified, known lengths. By measuring a gauge block with the micrometer and comparing the reading to the block’s true size (and noting any zero error when the jaws are closed), you can confirm the micrometer is measuring correctly across its range. You can also stack blocks to test multiple distances and check consistency. Dial test indicators measure small deflections and are not a fixed length standard, so they aren’t used to verify a micrometer. Calipers are less precise and can introduce larger errors, making them less suitable for checking micrometer accuracy. Feeler gauges assess gaps rather than provide a precise fixed length, so they don’t serve as a calibration reference for a micrometer. Gauge blocks remain the best choice for this purpose.

The main idea is using a precise length standard to verify a micrometer’s accuracy. Gauge blocks provide that reference because they are manufactured to tightly specified, known lengths. By measuring a gauge block with the micrometer and comparing the reading to the block’s true size (and noting any zero error when the jaws are closed), you can confirm the micrometer is measuring correctly across its range. You can also stack blocks to test multiple distances and check consistency.

Dial test indicators measure small deflections and are not a fixed length standard, so they aren’t used to verify a micrometer. Calipers are less precise and can introduce larger errors, making them less suitable for checking micrometer accuracy. Feeler gauges assess gaps rather than provide a precise fixed length, so they don’t serve as a calibration reference for a micrometer. Gauge blocks remain the best choice for this purpose.