Which instrument incorporates a calibrated screw and is widely used for precise measurement of components?

• A. Vernier caliper
• B. Micrometer
• C. Dial caliper
• D. Magnetic base

Answer: (B)

The micrometer uses a calibrated screw to convert tiny rotations into precise linear movement, giving very fine measurement resolution. When you rotate the thimble, the spindle moves toward or away from the anvil by a fixed amount each turn (the screw pitch, typically 0.5 mm per revolution). The sleeve scale provides the main reading, while the thimble graduation adds a fractional part, usually to 0.01 mm, so you can read measurements with high precision. This setup makes it ideal for measuring outside diameters, thicknesses, or small components where a caliper’s precision isn’t enough. A vernier or dial caliper can measure well, but they generally don’t reach the same level of precision as a micrometer. The magnetic base is just a mounting accessory, not a measuring tool.