Which tool is typically used to measure holes in machining?

The tool commonly used to measure holes in machining is a dial bore gauge. This specialized measuring instrument is designed specifically for checking the internal diameters of holes with high precision. It consists of a dial indicator mounted on a precision gauge that can be inserted into the hole. As the gauge is adjusted to fit snugly within the bore, any variations in size can be accurately read on the dial.

One key feature of dial bore gauges is their ability to detect slight imperfections in the hole's diameter, whether they are due to wear, tooling issues, or other factors. This level of precision is crucial in machining processes where hole specifications are critical to the functionality of the parts being produced.

While calipers can measure larger diameters and external dimensions, they may not provide the same level of accuracy for internal measurements. Micrometers are excellent for measuring external diameters and can measure depth as well, but they are less practical for accessing holes compared to dial bore gauges. Height gauges are designed for measuring vertical dimensions and are not applicable to hole measurement specifically. Therefore, the dial bore gauge stands out as the most appropriate choice for measuring holes effectively.