The test is divided into internal and external screw thread plug gauge and thread ring, there is a sheet-type gauge thread gauge according tooth.

Threaded plug
     Thread plug gauge to measure the internal thread size of the correctness of the tools can be divided into ordinary coarse teeth, fine teeth, and pipe thread three.

Threaded ring
     Thread ring gauge is used to measure the accuracy of the outer thread size, through the end of one, only the end of one.