Threaded Ring Gauges for Pipe Threads with Calibration Certificate

These gauges come with a certificate that’s traceable to NIST, confirming they were calibrated in a lab. The certificate, sometimes called a test report or a long-form certificate, includes the tested measurements. Use these gauges to verify whether external pipe threads are within tolerance.
Use gauges with NPT, NPTF, and BSPT threads on their own. If it takes no more than one turn for the gauge to sit flush against the end of your threads, they’re within tolerance.
For technical drawings and 3-D models, click on a part number.
Pipe Size | Thread Type | Hardness | Material | Pitch Dia. Tolerance | Each | |
NPT Threads | ||||||
---|---|---|---|---|---|---|
1/16 | NPT | Rockwell C60 | Tool Steel | -0.0002" to 0.0002" | 00000000 | 0000000 |
1/8 | NPT | Rockwell C60 | Tool Steel | -0.0002" to 0.0002" | 00000000 | 000000 |
1/4 | NPT | Rockwell C60 | Tool Steel | -0.0002" to 0.0002" | 00000000 | 000000 |
3/8 | NPT | Rockwell C60 | Tool Steel | -0.0002" to 0.0002" | 00000000 | 000000 |
1/2 | NPT | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
3/4 | NPT | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
1 | NPT | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
1 1/4 | NPT | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
1 1/2 | NPT | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
2 | NPT | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
2 1/2 | NPT | Rockwell C60 | Tool Steel | -0.0005" to 0.0005" | 00000000 | 000000 |
3 | NPT | Rockwell C60 | Tool Steel | -0.0005" to 0.0005" | 00000000 | 000000 |
4 | NPT | Rockwell C60 | Tool Steel | -0.0005" to 0.0005" | 00000000 | 00000000 |
Threaded Ring Gauges for NPT Pipe Threads with Calibration Certificate

To ensure accuracy of external NPT pipe thread measurements, these gauges include a certificate of calibration traceable to NIST that states they’ve passed a test for accuracy.
For technical drawings and 3-D models, click on a part number.
Pipe Size | Pitch Diameter Tolerance | Hardness | Material | Each | |
Class X | |||||
---|---|---|---|---|---|
1/16 | -0.0002" to 0.0002" | Rockwell C60 | Tool Steel | 00000000 | 0000000 |
1/8 | -0.0002" to 0.0002" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
1/4 | -0.0002" to 0.0002" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
3/8 | -0.0002" to 0.0002" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
1/2 | -0.0003" to 0.0003" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
3/4 | -0.0003" to 0.0003" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
1 | -0.0003" to 0.0003" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
1 1/4 | -0.0003" to 0.0003" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
1 1/2 | -0.0003" to 0.0003" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
2 | -0.0003" to 0.0003" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
2 1/2 | -0.0005" to 0.0005" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
3 | -0.0005" to 0.0005" | Rockwell C60 | Tool Steel | 00000000 | 000000 |
4 | -0.0005" to 0.0005" | Rockwell C60 | Tool Steel | 00000000 | 00000000 |
Threaded Ring Gauges for Pipe Threads

Confirm that external pipe threads are sized within tolerance. Manufactured with precision, these gauges meet tight thread tolerances themselves.
Use gauges with NPT, NPTF, and BSPT threads on their own for tests—if it takes no more than one turn for the gauge to sit flush against the end of the threads, they’re within tolerance.
For technical drawings and 3-D models, click on a part number.
Pipe Size | Hardness | Material | Pitch Dia. Tolerance | Each | |
NPT Threads | |||||
---|---|---|---|---|---|
1/16 | Rockwell C60 | Tool Steel | -0.0002" to 0.0002" | 0000000 | 0000000 |
1/8 | Rockwell C60 | Tool Steel | -0.0002" to 0.0002" | 00000000 | 000000 |
1/4 | Rockwell C60 | Tool Steel | -0.0002" to 0.0002" | 00000000 | 000000 |
3/8 | Rockwell C60 | Tool Steel | -0.0002" to 0.0002" | 00000000 | 000000 |
1/2 | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
3/4 | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
1 | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
1 1/4 | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
1 1/2 | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
2 | Rockwell C60 | Tool Steel | -0.0003" to 0.0003" | 00000000 | 000000 |
2 1/2 | Rockwell C60 | Tool Steel | -0.0005" to 0.0005" | 00000000 | 000000 |
3 | Rockwell C60 | Tool Steel | -0.0005" to 0.0005" | 00000000 | 000000 |
4 | Rockwell C60 | Tool Steel | -0.0005" to 0.0005" | 00000000 | 00000000 |