Threaded plug gauge for circular knife hole inspection

Some customers will ask us to use threaded plug gauge to check the inner hole of the circular knife.

When the threaded hole is inspected with a threaded plug gauge, sometimes the pass will not pass and the stop will pass. What is going on?

The stop gauge is used to verify the actual ‘the retention stop of the threaded hole, indicating that the actual diameter of the threaded hole is too large to block the stop gauge. The general rule is used to check the working diameter of the threaded hole, the complete tooth type and the standard screw length, and secondly the large diameter of the threaded hole.

The general rule does not indicate that the diameter of the threaded hole is small, for two reasons: one is that the medium diameter is too small or the large diameter is too small, but because of the stop, the situation does not exist; the second is the pitch or the tooth shape. The half-angle error is too large, which hinders the passage of the regulations.

There are two reasons for the adoption of the stop regulation. First, the stop gauge is a truncated tooth type (that is, the height of the tooth type is small), so when the half angle error is large, the stop gauge can pass and the general rule may not pass. Secondly, when the cumulative error of the pitch is large, because the number of deductions is small, the accumulated error in the range of 2-3 deductions of the stop is not enough to block the passage of the stop, but it is constituted within the range of the number of buckles of the general regulations. The cumulative error is enough to prevent the passage of regulations. Then there was a phenomenon that the regulations were not passed and the rules were passed.

In summary, the general rule can not be passed, the stop rule indicates that the threaded hole is unqualified, and the actual diameter is too large, but the large diameter may be too small, or the pitch and the half angle of the tooth type are too large. In fact, as long as the occupation of the pass or the stop through one of the conditions, the threaded hole is unqualified.