1. Standard conditions for smooth plug gauge measurement: the temperature is 20°C, and the measuring force is zero.
2. The gauge that checks the maximum physical size of the workpiece (that is, the hole is the smallest and the shaft is the maximum limit size) is called a general gauge.
The gauge that checks the minimum physical size of the workpiece (that is, the hole is the largest and the shaft is the smallest limit size) is called a stop gauge.
3. The gauges that conform to the principle of judging the limit size (that is, the Taylor principle) are as follows:
The gauging face of a go gauge shall be a complete surface corresponding to the shape of the hole or shaft (commonly called a full-form gauge), of dimensions equal to the largest physical dimension of the workpiece, and of a length equal to the mating length.
The measuring surface of the stop gauge should be point-shaped, and the dimension between the two measuring surfaces is equal to the minimum physical size of the workpiece.
If the gauge conforming to Taylor’s principle is inconvenient or difficult to use in some occasions, the gauge that deviates from Taylor’s principle can be used under the condition that the shape error of the inspected workpiece will not affect the matching properties.
4. Inspect the workpiece with a gauge that conforms to this standard. If the pass gauge can pass but the stop gauge cannot pass, the workpiece should be a qualified product.
5. When the manufacturer inspects the workpiece, the operator should use new or less worn general gauges; the inspection department should use the same form as the operator and more worn general gauges.
When the user representative checks the workpiece with the gauge, the go gauge should be close to the maximum physical size of the workpiece, and the stop gauge should be close to the minimum physical size of the workpiece.
6. Inspect the workpiece with a gauge that conforms to this standard. If there is any dispute in the judgment, the gauge with the following dimensions should be used to resolve it;
The general gauge should be equal to or close to the maximum physical dimension of the workpiece;
The stop gauge should be equal to or close to the minimum physical dimension of the workpiece;