What type of measurement tool is used to check the depth of a hole?

A depth gauge is specifically designed to measure the depth of holes, slots, and recesses with precision. It typically consists of a long, slender shaft with a measuring end that can extend down into the hole being measured. The readings on a depth gauge allow machinists to easily determine how deep a hole is, making it an essential tool for ensuring that machining operations meet design specifications.

In contrast, a ruler is a general measurement tool that provides linear measurements but is not suited for measuring depth accurately. A caliper can measure both internal and external dimensions but is not specifically optimized for depth measurements. A height gauge is primarily used for measuring vertical dimensions and is not designed for depth measurement in the same way a depth gauge is. This specialization in measuring depth gives the depth gauge its critical role in machining and inspection processes.