When measuring plate thickness, the most accurate reading is given by a:

• A. Steel ruler
• B. Steel tape
• C. Mechanical gage (micrometer)
• D. Feeler gage

Answer: (C)

Measuring plate thickness with the greatest accuracy comes from using a mechanical micrometer. Its finely threaded screw and calibrated scale move the spindle toward the anvil in very small, repeatable steps, providing readings with high resolution (often to 0.01 mm or 0.001 in) and consistent contact pressure for repeatable results. A steel ruler or steel tape has coarse divisions and can bend or tilt, introducing larger errors. A feeler gauge relies on selecting the blade that just fits and depends on judgment and variable pressure, giving only an approximate measurement. The micrometer’s combination of fine resolution and controlled contact makes it the most precise option for thickness measurements.