Identify one common tool used for measuring dimensions in machining.

A caliper is a precise measuring tool commonly used in machining to measure the dimensions of an object, such as the distance between two opposite sides or the diameter of a hole. Calipers can provide both internal and external measurements and can be highly accurate, often reading to a thousandth of an inch or millimeter, depending on the type of caliper used—whether it's a Vernier, dial, or digital caliper. This level of precision makes calipers essential for ensuring that machining processes produce parts that meet exact specifications.

Rulers, while useful for general measurements, do not offer the same level of accuracy as calipers, especially when measuring small or intricate parts. Drills are cutting tools used to create holes and do not measure dimensions. Anvils, typically part of a blacksmith's setup, serve as a surface for shaping metal rather than measuring dimensions. Thus, the versatility and precision of calipers make them a standard choice in machining applications.