A limit gauge is not a measuring gauge. Just they are used as inspecting gauges.
· A limit gauge is not a measuring gauge. Just they are used as inspecting gauges.
· The limit gauges are used in inspection by methods of attributes.
· This gives the information about the products which may be either within the prescribed limit or not.
· By using limit gauges report, the control charts of P and C charts are drawn to control invariance of the products.
· This procedure is mostly performed by the quality control department of each and every industry.
· Limit gauge are mainly used for checking for cylindrical holes of identical components with a large numbers in mass production.
Purpose of using limit gauges
· Components are manufactured as per the specified tolerance limits, upper limit and lower limit. The dimension of each component should be within this upper and lower limit.
· If the dimensions are outside these limits, the components will be rejected.
· If we use any measuring instruments to check these dimensions, the process will consume more time. Still we are not interested in knowing the amount of error in dimensions.
· It is just enough whether the size of the component is within the prescribed limits or not. For this purpose, we can make use of gauges known as limit gauges.
The common types are as follows:
1) Plug gauges.
2) Ring gauges.
3) Snap gauges.
TAYLOR’ S PRINCIPLE
It states that GO gauge should check all related dimensions. Simultaneously NOGO gauge should check only one dimension at a time.
Maximum metal condition
It refers to the condition of hole or shaft when maximum material is left on i.e. high limit of shaft and low limit of hole.
Minimum metal condition
If refers to the condition of hole or shaft when minimum material is left on such as low limit of shaft and high limit of hole.
Applications of Limit Gauges
1. Thread gauges
2. Form gauges
3. Serew pitch gauges
4. Radius and fillet gauges
5. Feeler gauges
6. Plate gauge and Wire gauge