Npt Ring Gauges | McMaster-Carr

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26 Products

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.

Class X Gauge—NPT Thread

Use gauges with NPT 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.

Pipe Size	Hardness	Material	Pitch Dia. Tolerance	Certificate Type		Each
1/16	Rockwell C60	Tool Steel	-0.0002" to 0.0002"	Calibration Certificate Traceable to NIST	2121A131	0000000
1/8	Rockwell C60	Tool Steel	-0.0002" to 0.0002"	Calibration Certificate Traceable to NIST	2121A132	000000
1/4	Rockwell C60	Tool Steel	-0.0002" to 0.0002"	Calibration Certificate Traceable to NIST	2121A133	000000
3/8	Rockwell C60	Tool Steel	-0.0002" to 0.0002"	Calibration Certificate Traceable to NIST	2121A134	000000
1/2	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	Calibration Certificate Traceable to NIST	2121A135	000000
3/4	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	Calibration Certificate Traceable to NIST	2121A136	000000
1	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	Calibration Certificate Traceable to NIST	2121A137	000000
1 1/4	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	Calibration Certificate Traceable to NIST	2121A138	000000
1 1/2	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	Calibration Certificate Traceable to NIST	2121A139	000000
2	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	Calibration Certificate Traceable to NIST	2121A141	000000
2 1/2	Rockwell C60	Tool Steel	-0.0005" to 0.0005"	Calibration Certificate Traceable to NIST	2121A142	000000
3	Rockwell C60	Tool Steel	-0.0005" to 0.0005"	Calibration Certificate Traceable to NIST	2121A143	000000
4	Rockwell C60	Tool Steel	-0.0005" to 0.0005"	Calibration Certificate Traceable to NIST	2121A145	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.

Class X Gauge—NPT Thread

Use gauges with NPT 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.

Pipe Size	Hardness	Material	Pitch Dia. Tolerance		Each
1/16	Rockwell C60	Tool Steel	-0.0002" to 0.0002"	2365A21	0000000
1/8	Rockwell C60	Tool Steel	-0.0002" to 0.0002"	2365A211	000000
1/4	Rockwell C60	Tool Steel	-0.0002" to 0.0002"	2365A212	000000
3/8	Rockwell C60	Tool Steel	-0.0002" to 0.0002"	2365A213	000000
1/2	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	2365A214	000000
3/4	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	2365A215	000000
1	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	2365A216	000000
1 1/4	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	2365A217	000000
1 1/2	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	2365A218	000000
2	Rockwell C60	Tool Steel	-0.0003" to 0.0003"	2365A219	000000
2 1/2	Rockwell C60	Tool Steel	-0.0005" to 0.0005"	2365A148	000000
3	Rockwell C60	Tool Steel	-0.0005" to 0.0005"	2365A149	000000
4	Rockwell C60	Tool Steel	-0.0005" to 0.0005"	2365A151	00000000