Limit gauges are used to check the dimensions of a manufactured component. As gauges are without scale, we are unable to use it to determine the actual size of dimensions of parts. They are different from a conventional measuring tool. We use a limit gauge to inspect whether a work piece is within the specified tolerance. They are also often known as a Go and No-Go gauge. A principle of using such gauges, is for the Go end to be used to check that the dimension of the part passes inspection. On the other hand, the No-Go gauge should not be able to pass the same dimension of the part. It serves as a check when a measured part fails inspection.
The Go- and No-Go gauges are produced according to the dimensions of the manufactured component. The Go gauge is usually equivalent to the minimum permissible dimension of the component. The No Go gauge is equivalent to the maximum permissible dimension of the measured component.
Limit gauges are precise and user friendly. They are normally produced to one tenth of the tolerance of the component they are used to measure. For instance, if the tolerance of the manufactured part stands at 0.07 mm, the limit gauge is usually precisely produced to 0.007 mm. Limit gauges are also wear and corrosion resistant. Ideally, they should also be produced with a thermally stable material. It should be resistant to expansion and contraction in different environmental conditions.
Many of us believe that measuring manufactured parts is the ideal method. However, this may not necessarily be the most practical solution all the time. It is time consuming to measure each dimension of your workpiece in big volumes. Limit gauges offer a quicker and easier way to check parts in large quantities. Besides this, we would want to achieve accuracy of the inspection and still be able to do it in the most economical way. This makes limit gauges an ideal solution for repetitive checking of manufactured parts. Other alternatives of checking dimensions using precision instruments, like the caliper and micrometer, tend to be time consuming and requires skilled or semi-skilled operators.
