What is a plug gauge

A measuring tool commonly used includes a circular hole plug gauge and a threaded plug gauge. The circular hole plug gauge is made into a cylindrical shape, with two ends being the through end and the stop end, used to check the diameter of the hole. Thread plug gauge is a tool for measuring the accuracy of internal thread dimensions. This plug gauge can be divided into three types: regular coarse thread, fine thread, and pipe thread. Thread plug gauges with a pitch of 0.35 millimeters or less and a second level accuracy or higher, as well as thread plug gauges with a pitch of 0.8 millimeters or less and a third level accuracy, do not have end gauges. Thread plug gauges below 100mm are taper shank thread plug gauges. A double threaded plug gauge with a diameter of over 100 millimeters.