What is a micrometer?

• A. A tool for cutting wood.
• B. A precise measurement device often found in machine shops for measuring the outside of objects.
• C. A measurement tape that coils.
• D. A soft-faced mallet.

Answer: (B)

A micrometer is a precision measuring instrument used to determine the outside dimensions of small objects with high accuracy. In an outside micrometer, a spindle moves toward a fixed anvil as you turn a very precise screw; the tiny movement is read on a sleeve scale and a rotating thimble, giving measurements in thousandths of an inch (or hundredths of a millimeter). This level of precision is essential in machine shops for checking diameters, thicknesses, or other external dimensions to tight tolerances. It's not a tool for cutting, not a coilable tape measure, and not a mallet, but a dedicated instrument for exact sizing.