How are threads specified on metric bolts?

The specification of threads on metric bolts primarily involves the pitch of the threads. Pitch refers to the distance between adjacent threads, measured in millimeters, and it is a critical dimension that helps in determining how tightly the threads fit together. In the metric system, pitch is expressed in millimeters per thread; for example, a bolt with a pitch of 1.0 means that there is one millimeter between the peaks of consecutive threads.

This pitch measurement is essential because it affects the bolt's ability to securely fasten parts together. The correct pitch ensures compatibility with the corresponding threaded hole or nut, which directly affects the bolt's performance under load. Thus, specifying the pitch is crucial when selecting or ordering metric bolts. Other options, such as the diameter, length, and type of threads, are also important specifications but do not directly indicate how threads are measured in the context of metric bolts.