3/8 Pipe Size Pipe Locknuts

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20 Products

Low-Pressure Stainless Steel Threaded Pipe Locknuts

Use these locknuts in a low-pressure pipe line.

Locknuts thread onto the male end of a fitting to provide extra holding power so the fitting won’t loosen from vibration.

NPTF (Dryseal) threads and NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.

304 Stainless Steel—304 stainless steel locknuts have very good corrosion resistance.

316 Stainless Steel—316 stainless steel locknuts have excellent corrosion resistance.

ANSI/MSS SP-114—Locknuts that meet ANSI/MSS SP-114 adhere to high-quality standards for heat treating, material thickness, and marking.

DIN 431—Locknuts that meet DIN 431 comply with international standards for pipe locknut dimensions.

							For Pipe		For Flange			304 Stainless Steel		316 Stainless Steel
	Pipe Size	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.	For Use With	Pressure Class	Fabrication	Schedule	Material	Class	Material	Specs. Met		Each		Each
NPSL Female



		3/8	300 psi @ 72° F	150 psi @ 350° F	Air, Natural Gas, Oil, Steam, Water	150	Heat Treated	40	304 Stainless Steel, 304/304L Stainless Steel	150	304 Stainless Steel, 304/304L Stainless Steel	ANSI/MSS SP-114, ASTM A351	4464K583	000000	———	0


		3/8	300 psi @ 72° F	150 psi @ 350° F	Air, Natural Gas, Oil, Steam, Water	150	Heat Treated	40	316 Stainless Steel, 316/316L Stainless Steel	150	304 Stainless Steel, 304/304L Stainless Steel	ANSI/MSS SP-114, ASTM A351	———	0	4452K673	000000


		BSPP Female



				3/8	Not Rated	Not Rated	Air, Natural Gas, Oil, Steam, Water	—	—	—	304 Stainless Steel, 304/304L Stainless Steel	—	304 Stainless Steel, 304/304L Stainless Steel	DIN 431	9027N103	0000	———	0

Conduit Locknuts

Secure threaded conduit fittings to knockouts. These locknuts keep fittings from shifting, so connections stay stable and wiring is protected inside electrical boxes or enclosures.

For Plastic Fittings

Nylon—Lightweight and chemical resistant, these fittings won't corrode.


NPT Thread







	Nylon

	3/8	3185K111	00000


	3/8	7877N103	0000

Low-Pressure Brass and Bronze Threaded Pipe Locknuts

Use these locknuts in low-pressure flow applications. They have good corrosion resistance.

Locknuts thread onto the male end of a fitting to provide extra holding power so the fitting won’t loosen from vibration.

NPSL Thread—NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.

DIN 431—Locknuts that meet DIN 431 comply with international standards for pipe locknut dimensions.

NSF/ANSI 61—Locknuts rated for use with drinking water meet NSF/ANSI 61 safety standards.

								For Pipe		For Flange
	Pipe Size	Hex Wd.	Lg.	Max. Pressure @ Temp.	For Use With	Pressure Class	Material	Schedule	Material	Class	Material	Specs. Met	Food Industry Std.		Each
NPSL Female



		3/8	1"	9/32"	200 psi @ 72° F	Air, Drinking Water, Natural Gas, Oil	125	Brass	40	Brass	150	Brass	ASME B1.20.1, ASME B16.15, ASTM A584	NSF/ANSI 61	4429K123	00000


		BSPP Female



				3/8	27 mm	7 mm	Not Rated	Air, Natural Gas, Oil	—	Brass	—	Brass	—	Brass	DIN 431	—	3538N13	0000

Stainless Steel Hex Panel Nuts

All of these stainless steel panel nuts have some chemical resistance. They can be fastened with a wrench for more torque while tightening than knurled panel nuts. Also known as dress nuts, they are extremely thin for use in tight spaces such as electrical panels.

NPSM Thread About NPSM Thread

18-8 Stainless Steel—18-8 stainless steel nuts have good chemical resistance. They may be mildly magnetic.

316 Stainless Steel—316 stainless steel nuts have excellent chemical resistance and can be used in saltwater environments.

	Wd.	Ht.	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	3/8	13/16"	17/64"	1	91862A535	00000


	316 Stainless Steel



			3/8	13/16"	17/64"	1	94177A170	00000

Steel Hex Panel Nuts

Fasten these panel nuts with a wrench for more torque while tightening than knurled panel nuts. Also known as dress nuts, they're extremely thin for use in tight spaces such as electrical panels.

NPSM Thread About NPSM Thread

Black-Oxide Steel—Black-oxide steel nuts have a dark surface color.

	Wd.	Ht.	Pkg. Qty.		Pkg.
Black-Oxide Steel



	3/8	13/16"	17/64"	1	94162A170	00000


	3/8	13/16"	9/32"	1	94162A180	0000
	3/8	13/16"	19/64"	1	94162A190	0000

Low-Pressure Plated Brass Threaded Pipe Locknuts

Used in low-pressure pipe lines, these brass locknuts have a plating that makes them shiny and improves corrosion resistance.

Locknuts thread onto the male end of a fitting to provide extra holding power so the fitting won’t loosen from vibration.

Chrome-Plated Brass—Chrome-plated brass locknuts are shinier and withstand corrosion better than nickel-plated brass locknuts.

									For Pipe
	Pipe Size	Hex Wd.	Lg.	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.	For Use With	Pressure Class	Material	Schedule	Material	Specs. Met		Each
NPT Female



		3/8	1"	9/32"	200 psi @ 72° F	125 psi @ 400° F	Air, Natural Gas, Oil, Steam, Water	125	Chrome-Plated Brass	40	Brass	ASTM B456	9162K183	000000

High-Pressure Brass Threaded Pipe Locknuts

These locknuts have the strength to handle high-pressure applications. They are brass for good corrosion resistance.

Locknuts thread onto the male end of a fitting to provide extra holding power so the fitting won’t loosen from vibration.

NPSL Thread—NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.

	Hex Wd.	Lg.	Max. Pressure @ Temp.	For Use With	Material	Fabrication		Each
NPSL Female



	3/8	1"	5/16"	1,000 psi @ 72° F	Air, Natural Gas, Oil, Water	Brass	Machined	50785K143	00000

Extreme-Pressure Steel Threaded Pipe Locknuts

The strongest steel locknuts we offer, these can withstand extreme-pressure applications.

Locknuts thread onto the male end of a fitting to provide extra holding power so the fitting won’t loosen from vibration.

												For Pipe		For Flange
	Pipe Size	Dash Size	Hex Wd.	Lg.	Gasket Material	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.	For Use With	Temp. Range, ° F	Material	Fabrication	Schedule	Material	Class	Material		Each
NPT Female



		3/8	06	7/8"	9/32"	PTFE	10,000 psi @ 72° F	5,000 psi @ 500° F	Air, Hydraulic Fluid, Natural Gas, Oil, Steam, Water	-100 to 500	Zinc-Yellow-Chromate-Plated Steel	Machined	XXH	Steel	1500	Steel	5530K18	000000

Low-Pressure Aluminum Threaded Pipe Locknuts

In addition to being lightweight, these aluminum locknuts offer good corrosion resistance. Use them in low-pressure flow applications. To prevent cracking, do not tighten more than a _1/4-turn past hand tight.

Locknuts thread onto the male end of a fitting to provide extra holding power so the fitting won’t loosen from vibration.

NPSL Thread—NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.

								For Pipe		For Flange
	Pipe Size	Hex Wd.	Lg.	Max. Pressure @ Temp.	For Use With	Pressure Class	Material	Schedule	Material	Class	Material		Each
NPSL Female



		3/8	1 1/8"	3/16"	150 psi @ 72° F	Air, Oil, Water	150	6061 Aluminum	40	Aluminum	125	Aluminum	44705K413	00000

Extreme-Pressure Stainless Steel Threaded Pipe Locknuts

With the strength to handle extreme pressures, these locknuts can be used to connect equipment in hydraulic fluid lines.

Locknuts have a gasket, which creates a tight seal without the need for PTFE tape; screw one onto the male end of a fitting for extra holding power.

303 Stainless Steel—303 stainless steel locknuts have very good corrosion resistance.

									303 Stainless Steel
	Pipe Size	Dash Size	Hex Wd.	Lg.	Gasket Material	Max. Pressure @ Temp.	For Use With	Temp. Range, ° F		Each
NPT Female



		3/8	06	7/8"	9/32"	PTFE	10,000 psi @ 72° F	Air, Hydraulic Fluid, Natural Gas, Oil, Water	-300 to 500	5530K39	000000

Low-Pressure Galvanized Iron and Steel Threaded Pipe Locknuts

The galvanized finish on these locknuts provides fair corrosion resistance. Locknuts are for use in low-pressure applications.

Locknuts thread onto the male end of a fitting to provide extra holding power so the fitting won’t loosen from vibration.

NPSL Thread—NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.

									For Pipe		For Flange
	Pipe Size	Hex Wd.	Lg.	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.	For Use With	Pressure Class	Material	Schedule	Material	Class	Material	Specs. Met		Each
NPSL Female



		3/8	1"	0.28"	Not Rated	Not Rated	Air, Natural Gas, Oil, Steam, Water	150	Galvanized Iron	40	Galvanized Steel	150	Galvanized Steel	ASME B16.14	4638K613	00000

Low-Pressure Iron and Steel Threaded Pipe Locknuts

Use these locknuts for low-pressure applications in noncorrosive environments.

Locknuts thread onto the male end of a fitting to provide extra holding power so the fitting won’t loosen from vibration.

NPTF (Dryseal) threads, NPSC (National Pipe Straight Coupling) threads, and NPSL (National Pipe Straight Locknut) threads are compatible with NPT threads.

DIN 431—Locknuts that meet DIN 431 comply with international standards for pipe locknut dimensions.

									For Pipe
	Pipe Size	Hex Wd.	Lg.	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.	For Use With	Pressure Class	Material	Schedule	Material	For Flange Material	Specs. Met		Each
NPSL Female



		3/8	1"	9/32"	Not Rated	Not Rated	Air, Natural Gas, Oil, Steam, Water	150	Iron	40	Steel	Iron, Steel	ASME B16.14	44605K211	00000


		BSPP Female



				3/8	27 mm	7 mm	Not Rated	Not Rated	Air, Natural Gas, Oil, Steam, Water	—	Steel	—	Steel	Steel	DIN 431	3555N13	0000