Precision thread gauges, also known as screw gauges, are measuring tools used to measure the pitch diameter of screws, nuts, and bolts. They are essential tools in manufacturing and engineering, as they help ensure the correct thread dimensions of parts, which is critical for proper fit and function.

There are two main types of precision thread gauges: thread plug gauges and thread ring gauges. Thread plug gauges are used to check the accuracy and pitch of internal threads, while thread ring gauges are used to check the accuracy and pitch of external threads.

Precision thread gauges are available in various designs and sizes, depending on the application and industry. The most common thread standards used are the unified national coarse (UNC) and unified national fine (UNF) standards. Thread gauges are also available in metric and Whitworth standards.

The accuracy of precision thread gauges is critical, and they are manufactured to very high standards. The gauges are made of high-quality materials, such as hardened steel or tungsten carbide, to ensure durability and accuracy. They must be regularly calibrated to ensure that they remain within their specified tolerances.