Grade 9 Steel Hex Nuts | McMaster-Carr

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36 Products

Thin-Profile Hex Nuts

About half the height of standard-profile nuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against another hex nut to hold it in place.

Medium-Strength Steel

These Grade 5 or Class 04 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.

Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.

Zinc-Yellow-Chromate-Plated Steel—With a more durable finish than clear zinc plating, these nuts are suitable for most wet and outdoor environments. However, they won't hold up to the harsh chemicals that stainless steel can.

Steel—Best for dry environments since moisture will cause these nuts to rust.

	Wd., mm	Ht., mm	Fastener Strength Grade/Class	Specs. Met	Certificate Type	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M18 × 1.5 mm	27	9	Class 04	DIN 439B, ISO 8675	—	10	90326A140	000000


	M18 × 2.5 mm	27	9	Class 04	DIN 439B, ISO 4035	—	10	90695A153	00000


	Zinc-Yellow-Chromate-Plated Steel



			M18 × 1.5 mm	27	9	Class 04	DIN 439B, ISO 8675	Material Certificate	5	93737A116	0000


			Steel



					M18 × 1.5 mm	27	9	—	DIN 936	—	10	90364A107	0000


					M18 × 1.5 mm	27	9	Class 04	DIN 439B, ISO 8675	—	10	90326A214	0000
					M18 × 2.5 mm	27	9	—	DIN 936	—	10	90370A107	00000
					M20 × 1.5 mm	30	9	—	DIN 936	—	10	90364A109	00000
					M20 × 2 mm	30	9	—	DIN 936	—	10	90364A108	00000
					M20 × 2.5 mm	30	9	—	DIN 936	—	10	90370A108	00000

Corrosion-Resistant Stainless Steel

18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

Black-Oxide 18-8 Stainless Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They resist rust in wet and outdoor environments, but won't hold up to the harsh chemicals that 316 stainless steel can.

Highly Corrosion-Resistant 316 Stainless Steel—Superior to 18-8 stainless steel, these nuts won't degrade when exposed to harsh weather, salt water, and most chemicals.

	Wd., mm	Ht., mm	Specs. Met	Certificate Type	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M18 × 1.5 mm	27	9	DIN 439B, ISO 8675	Material Certificate	1	91938A165	00000


	M18 × 1.5 mm	27	9	DIN 936	—	1	97013A117	0000
	M18 × 2.5 mm	27	9	DIN 439B, ISO 4035	Material Certificate	5	90710A150	00000
	M18 × 2.5 mm	27	9	DIN 936	—	5	90381A105	00000
	M20 × 1.5 mm	30	9	DIN 936	—	1	97013A113	0000
	M20 × 2.5 mm	30	9	DIN 936	—	1	90381A106	0000


	Black-Oxide 18-8 Stainless Steel



			M18 × 1.5 mm	27	9	DIN 439B, ISO 8675	—	1	97013A132	0000


			M18 × 2.5 mm	27	9	DIN 439B, ISO 4035	—	1	96315A123	0000


			Highly Corrosion-Resistant 316 Stainless Steel



					M18 × 1.5 mm	27	9	DIN 439B, ISO 8675	—	1	97289A131	0000


					M18 × 2.5 mm	27	9	DIN 936	—	1	97289A116	0000
					M20 × 2.5 mm	30	9	DIN 936	—	1	97289A117	0000

Weld Nuts

Add permanent threads to thin metal with our go-to weld nuts. Unlike press-fit and rivet nuts, these nuts fuse to the base metal, so they won’t twist and pull out. Three evenly spaced projections concentrate heat away from the threads to prevent them from deforming and create consistent welds. All have a collar pilot that guides the nut into the hole, holds it in place while welding, and protects the threads from weld spatter. You can also install them on thick pieces of metal.

Steel—Best for dry environments since moisture will cause them to rust. Made of uncoated steel, these nuts require minimal prep. Weld them to uncoated steel surfaces.

18-8 Stainless Steel—Suitable for outdoor use, these nuts resist rust from water and mild chemicals. Weld them to stainless steel surfaces.

				Collar, mm
	Thread Size	Wd., mm	Ht., mm	Dia.	Ht.	For Hole Dia., mm	Specs. Met	Pkg. Qty.		Pkg.
Steel



		M4 × 0.7 mm	9	2.85	6	0.65	6	DIN 929	100	93337A500	000000


		18-8 Stainless Steel



				M4 × 0.7 mm	9	2.9	6	0.65	6	DIN 929	50	93418A300	0000

Coupling Nuts

Also known as extension nuts, these are commonly used to connect lengths of threaded rod and join threaded parts.

Low-Strength Steel

Rated Grade 2 or lower, these are about half as strong as medium-strength steel coupling nuts. Use them with threaded rods that have a comparable strength rating to avoid stripping threads during installation.

Zinc-Plated Steel—A step up from plain steel, the zinc plating withstands occasional exposure to moisture.

Black-Oxide Steel—A dark, matte coating creates a finished look. Nuts offer minimal corrosion resistance, so they're best for dry environments.

Steel—Best for dry environments since moisture will cause these nuts to rust.

	Lg.	Wd.	Threading	Min. Thread Lg.	Certificate Type		Each
Zinc-Plated Steel



	M3 × 0.5 mm	9 mm	6 mm	Fully Threaded	—	Material Certificate	93355A530	00000


	Black-Oxide Steel



			M3 × 0.5 mm	9 mm	6 mm	Fully Threaded	—	—	93020A103	0000


			Steel



					2"-4 1/2	9"	3 1/4"	Partially Threaded	4 3/8"	—	90264A706	000000

Corrosion-Resistant Stainless Steel

18-8 Stainless Steel—The choice for wet and outdoor environments, these nuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

							Each
	Thread Size	Lg., mm	Wd., mm	Threading	Certificate Type		1-9	10-49	50-Up
18-8 Stainless Steel



		M3 × 0.5 mm	9	5	Fully Threaded	Material Certificate	93590A103	00000	00000	00000


		Black-Oxide 18-8 Stainless Steel



				M3 × 0.5 mm	9	5	Fully Threaded	—	93590A319	0000	0000	0000

High-Profile Flange Nuts

30% taller than standard-profile nuts, these have a large gripping area so your wrench or socket won't slip off as you tighten them. They also engage more threads for extra gripping power. Nuts have a flange that distributes pressure evenly across the mounting surface without the need for a separate washer. They are ideal for securing screws in oversized or irregularly shaped holes since the flange covers a larger area than standard nuts. Also known as collar nuts.

High-Strength Steel

Rated Grade 8, Grade G, or Class 10, these are about 25% stronger than medium-strength steel nuts. They are commonly used to fasten components in valves, pumps, and motors. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.

Steel—Best for dry environments since moisture will cause these nuts to rust.

				Flange, mm
	Thread Size	Wd., mm	Ht., mm	Dia.	Thk.	Fastener Strength Grade/Class	Specs. Met	Pkg. Qty.		Pkg.
Steel



		M6 × 1 mm	10	9	14	3	Class 10	DIN 6331	50	90360A111	000000

Left-Hand-Thread Thin-Profile Hex Nuts

These nuts tighten when turned to the left. Use them with left-hand rods and screws to prevent counterclockwise-moving parts from loosening. About half the height of standard-profile nuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against another hex nut to hold it in place.

Medium-Strength Steel

These Grade 5 or Class 04 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.

Black-Oxide Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They offer minimal corrosion resistance, so they're best for dry environments.

Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.

	Wd., mm	Ht., mm	Fastener Strength Grade/Class	Specs. Met	Certificate Type	Pkg. Qty.		Pkg.
Black-Oxide Steel



	M18 × 1.5 mm	27	9	Class 04	ASTM A108, DIN 439B, ISO 8675	Material Certificate	1	90519A838	00000


	M18 × 2.5 mm	27	9	Class 04	ASTM A108, DIN 439B, ISO 4035	Material Certificate	1	90519A821	0000

Corrosion-Resistant Stainless Steel

Highly Corrosion-Resistant 316 Stainless Steel—Superior to 18-8 stainless steel, these nuts won't degrade when exposed to harsh weather, salt water, and most chemicals.

	Wd., mm	Ht., mm	Specs. Met		Each
Highly Corrosion-Resistant 316 Stainless Steel



	M18 × 1.5 mm	27	9	DIN 439B, ISO 8675	93031A138	000000

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.

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

								304 Stainless Steel
	Pipe Size	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.	For Use With	For Pipe Material	For Flange Material	Specs. Met		Each
BSPP Female



		3/4	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	9027N106	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.

	Hex Wd., mm	Lg., mm	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.	For Use With	Material	For Pipe Material	For Flange Material	Specs. Met		Each
BSPP Female



	3/4	36	9	Not Rated	Not Rated	Air, Natural Gas, Oil, Steam, Water	Steel	Steel	Steel	DIN 431	3555N15	00000

Electrical Insulating Nutdrivers

Prevent a dangerous zap if you accidentally touch a live circuit. With an insulated handle and shaft, these nutdrivers absorb up to 1,000 volts of electric shock to meet IEC and ASTM standards. Use them to work safely on circuit boards, control panels, and machines with a lingering charge.

Cushion Grip—Made of soft plastic to make gripping and squeezing the handle more comfortable.

			Shaft
Drive Size, mm	Bolt Clearance	Overall Lg.	Lg.	Overall Wd.	Material	Grip Style	Specs. Met		Each
5	5 7/8"	9"	5"	3/8"	Plastic-Coated Steel	Cushion	IEC 60900, ASTM F1505	54425A61	000000
10	5 7/8"	9"	4 9/16"	1/2"	Plastic-Coated Steel	Cushion	IEC 60900, ASTM F1505	54425A65	00000

Nutdrivers

Plain Grip

Tighten and loosen hex nuts for routine maintenance and repairs. With a hollow shaft, these nutdrivers reach nuts at the end of long bolts.

Black-Oxide Steel—These nutdrivers withstand occasional moisture.

Plain Grip—Made of hard plastic for durability.

			Shaft
Drive Size	Bolt Clearance	Overall Lg.	Lg.	Overall Wd.	Material	Grip Style		Each
9/16"	2 13/16"	9"	4"	13/16"	Black-Oxide Steel	Plain	8358A42	000000