1. Vernier caliper measurement method
Measure with vernier calipers, measure the major diameter of the screw thread, and measure the minor diameter and external dimensions of the nut. If the screw is corroded, first use a steel wire to remove the rust, and compare the measured data with the standard size.
Thread diameter measurement
Thread diameter measurement
Nut width measurement
Nut thickness measurement
2. Pitch gauge measurement method
Use the pitch gauge to measure the pitch. Before measuring with the pitch gauge, make sure that the major diameter of the screw thread measured in the previous step is within the allowable deviation range. If the thread fits the pitch gauge, it is judged as qualified.
3. Pass and stop gauge measurement method
This method is suitable for in-plant inspection. Through gauge and stop gauge measurement can accurately determine whether the screw is within the tolerance range. Only the through gauge (T) can be screwed in manually, and the stop gauge (Z) does not exceed one-third of the thread. It is judged as qualified, otherwise it is unqualified.
The measurement of the nut with the through stop gauge can accurately determine whether the nut is within the tolerance range. The through end (T end) can be manually screwed into the entire nut, and the stop end (Z end) cannot be manually screwed into the 1/3 thread of the tested nut. It is judged as qualified, otherwise it is unqualified.
Of course, the tensile test is also very important, which really reflects the tensile strength of the bolt.