What tool is typically used to measure diameter in a machining context?

In machining, a caliper is commonly used to measure the diameter of objects due to its design and versatility. Calipers come in various forms, which allow for internal, external, and depth measurements, making them suitable for a range of machining tasks. Their scale or digital readout provides the user with a clear measurement, which can be especially important in precision machining where accurate dimensions are critical.

Micrometers, while also capable of measuring diameter, are generally more specialized tools that excel in providing highly precise measurements in a narrower range and can be less versatile than calipers for varying size jobs. A ruler, although it can measure length and hence diameter indirectly, is not precise enough for the accuracy required in machining applications. Gage blocks are used for calibration and setting standards but are not practical for direct measurement of diameter in most machining tasks.

Thus, the caliper's design and adaptability for measuring different diameters make it the preferred tool in a machining context.