UNEF Plug Gauges | McMaster-Carr

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Thread Size

Thread Type

Thread Fit

Unified Standard Class 2B

Unified Standard Class 3B

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Accuracy Certificate Traceable to NIST

Calibration Certificate Traceable to NIST

Gauge Measurement Type

No-Go

Thread Direction

Right Hand

Finish

Chrome Plated

Size-Checking Gauge Class

Export Control Classification Number (ECCN)

EAR99

Hardness

Rockwell C70

Material

Tool Steel

DFARS Specialty Metals

Exempt

REACH

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RoHS

Compliant

U.S.–Mexico–Canada Agreement (USMCA) Qualifying

Yes

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24 Products

Go/No-Go Threaded Plug Gauges with Handle

Speed up thread tolerance checks—the handle on these gauges gives you a good grip to quickly thread and unthread go or no-go gauges. Use these gauges to make sure nuts, tapped holes, and other parts fall within tolerance. All are precisely manufactured to confirm thread fit. If the plug gauges wear down, you can insert new ones (not included) onto the taperlock handle.

A part is within tolerance if it’s easy to thread the go gauge into the part but difficult to thread the no-go gauge more than two turns.

Go/no-go gauges have both a go gauge on one end of the handle and a no-go gauge on the other to speed up tests. Go gauges check the minimum internal thread size. No-go gauges check the maximum internal thread size.

Class X Gauge

Double-Ended Taperlock

Handle

Accuracy Certificate Traceable to NIST—Gauges with an accuracy certificate traceable to NIST include verification from the manufacturer that their thread sizes are within tolerance. The certificate is also known as a certificate of compliance or a short-form certification.

Calibration Certificate Traceable to NIST—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.

For Class 2B Unified Standard Thread Fit—For inch threads, the higher the class number, the tighter the fit. Unified Standard Class 2B is standard and works for most applications.

For Thread Fit—Thread fit designates the tightness or looseness of mating threads.

	Thread Type	Pitch Dia. Tolerance	Hardness	Material	Features	Choose a Thread Fit		Each
Go/No-Go Gauges with Accuracy Certificate Traceable to NIST



	12-32	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A306	0000000


	1/4"-32	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A307	000000
	5/16"-32	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A308	000000
	3/8"-32	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A309	000000
	7/16"-28	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A311	000000
	1/2"-28	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A312	000000
	9/16"-24	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A313	000000
	5/8"-24	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A314	000000
	11/16"-24	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A315	000000
	3/4"-20	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A316	000000
	7/8"-20	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A317	000000


	1"-20	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	2366A319	000000


	Go/No-Go Gauges with Calibration Certificate Traceable to NIST



			12-32	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A63	000000


			1/4"-32	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A64	000000
			5/16"-32	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A65	000000
			3/8"-32	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A66	000000
			7/16"-28	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A67	000000
			1/2"-28	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A68	000000
			9/16"-24	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A69	000000
			5/8"-24	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A71	000000
			11/16"-24	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A72	000000
			3/4"-20	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A73	000000
			7/8"-20	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A74	000000


			1"-20	UNEF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B , Unified Standard Class 3B	3157A76	000000