What tool is often used to measure bolt diameter?

The caliper is a versatile measuring tool commonly used to measure the diameter of bolts accurately. One of the main reasons the caliper is well-suited for this task is its design, which allows it to measure both external and internal dimensions. When measuring a bolt's diameter, a caliper can easily slide over the surface, providing precise readings.

Calipers are capable of measuring in both imperial and metric units and usually have a scale marked on them, which can help users quickly determine the diameter. Unlike measuring tapes, which can be cumbersome for small dimensions, calipers offer a high degree of accuracy and can measure down to fractions of a millimeter or decimal inches. The user can simply place the jaws of the caliper around the bolt to obtain a direct measurement, making it a convenient and effective choice for this application.

Other measurement tools, while they have their own specific uses, might not provide the same level of precision needed for measuring bolt diameters. For instance, micrometers are excellent for very precise measurements, but they may not be as convenient for various bolt sizes. Digital gauges provide similar precision as calipers but might not be as universally accessible or easy to transport. Measuring tapes, while useful for longer lengths, are not ideal for measuring