When measuring, an instrument with a calibrated scale is used. The measuring instrument can be rigid or adjustable (caliper gauge). When gauging, the form or a measure is compared with a gauge that represents a desired measure. The gauge is rigid.
Both functions are used for thread cutting. They are used in both main applications.
Thread gauges are used to check the quality of a thread produced. Threads are standardized and so gauges can be used. Gauges usually have a good side and a bad side. It is marked with a red ring.
Thread templates are used to determine the pitch of a thread. The nominal size and the pitch are used to determine a thread. A caliper gauge is required to measure the nominal size.
The pitch and nominal diameter data can be used to determine the thread type and size by means of thread tables. Nut and bolts can be assigned in this way. Even before re-cutting defective threads, you should know exactly which type of thread is to be machined.