Understanding the Taylor Principle of Gauging
Taylor’s principle states that the “GO” gauge should always be designed so that it will cover the maximum metal condition (MMC) of as many dimensions as possible in the same limit gauge, whereas a “NOT GO” gauge should cover the maximum metal condition of one dimension only.
According to the rule, a GO plug gauge should have a full circular section and be of a full length of the hole, it has to control the diameter at any one point.
This ensures that any lack of straightness or parallelism of the hole will prevent the entry of the full-length GO plug gauge.
For example, let us assume that a bushing is to be inspected. The bush to mate a shaft. The shaft, therefore, opposed the part in relation to the bushing.
Therefore the form of “GO” plug gauge should exactly coincide with the form of the shaft.
For this purpose, the “GO” plug gauge must be of adequate length not less than the length of the future association of bushing and shaft.
If this condition is not satisfied, part inspection with the gauge may prove to be defective or even entirely that the bush being inspected has a curved axis and a short “GO” plug gauge is employed.
CHECKING A BUSH WITH A CURVED AXIS
The show plug gauge will pass through all the curves of the bent bushing. This will lead to the erroneous inclusion that the workplace is within the prescribed limits.
Actually, the problem such as bent bushing cannot match properly with the opposed part. A “GO” plug gauge of appropriate length will not pass through a part or curved bushing, and the error will be revealed.
A long “GO” plug gauge will check the cylindrical surface not in one direction but in a number of sections simultaneously.
Generally, the length of the “GO” plug gauge will check the cylindrical surface, not in one direction, but in a number of sections simultaneously.
The length of the “GO” plug gauge should not be less than 1.5 times the diameter of the hole. The length of the “NOT GO” gauge is kept smaller than the “GO” gauge.
