1、through regulation
     Before use: should measure after measure the relevant inspection agency inspection before they go into production in the field.
     When you use: should pay attention to the measured thread tolerance class and the deviation Tolerance class code and ring identified deviations same code (such as M24 * 1.5-6h and M24 * 1.5-5g two identical ring shape, which is not the same thread tolerance , misuse will generate batch defective products).
2、only the rules
     When you use: should pay attention to the measured thread tolerance class and the deviation identification code and ring tolerance level, the same error code
     Inspection measurement process: First, to clean up the thread measured oil and impurities, and then in the ring after being tested positive thread with thumb and index finger rotating ring gauge, screw thread length in the two pitches of qualified, otherwise, as unqualified goods.