Gauge

A gauge is a measuring device. A gauge can be as simple as a piece of string cut to a specific dimension or a cutout of an animated character with an outstretched arm and the caption, “You must be this tall to ride this attraction.”

On the other end of the sensitivity spectrum, a gauge can be a calibrated pressure sensing device or a laser measuring device.

In any event, the gauge compares an actual measurement to a set standard to allow the observer to make an assessment.

The measurement process depends on good maintenance and accuracy of the gauge, and in having well-trained employees taking the measurement. Gauge R&R (Gauge Repeatability and Reproducibility) is a formal method of ensuring good measurements.

Go/no-go gauges are a specialized device for checking that a tolerance falls within a certain range.

Many people confuse gauges and poka yoke devices. A gauge simply measures—it doesn’t prevent a process from using a part that is out of tolerance.

A poka yoke may include a gauge as part of the mistake-proofing device, but it must prevent an error, not just identify one.