Which instrument is used to measure outside diameters and lengths?

The instrument primarily used to measure outside diameters and lengths with great precision is the micrometer. Micrometers are designed specifically for measuring small dimensions accurately, typically in the range of millimeters. They operate using a calibrated screw mechanism that allows users to take precise measurements of the thickness or outside diameter of an object by placing it between the spindle and the anvil of the device.

When measuring outside diameters, the micrometer can provide readings with a level of accuracy that is crucial in engineering applications, where very slight deviations can significantly impact functionality and safety. The screw mechanism, along with the scale wrapped around the sleeve and the thimble, allows fine adjustments that help achieve precise measurements, thereby ensuring the accuracy required in engineering design and manufacturing.

The other instruments, while useful in their own right, are typically not as specialized for this type of measurement. For instance, a Vernier caliper is versatile and can measure both external and internal dimensions, as well as depths, but lacks the same level of precision as a micrometer for very small dimensions. A caliper gauge functions to measure the distance between its arms but is generally less precise for fine measurements compared to a micrometer. A dial indicator is mainly used for measuring small distances or assessing surface