Verify whether pipe fitting threads fall within tolerance. These gauges are attached to a handle, giving you a solid gripping point to thread and unthread them quickly. All are precisely manufactured to tight thread tolerances. If the gauges wear down, you can install new ones (not included) on the taperlock handle.

Use gauges with NPSM and BSPP threads for go/no-go tests. The end with a go gauge checks the minimum internal thread size, and the end with a no-go gauge checks the maximum. Your fitting is within tolerance if it’s easy to thread in the go gauge but difficult to thread the no-go gauge more than two turns.

Gauges with a calibration certificate traceable to NIST were calibrated in a lab. The certificate, sometimes called a test report or long-form certificate, details the tested measurements.