M42 Nuts | McMaster-Carr

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28 Products

About Hex Nuts

Choose a hex nut with the right profile, material, and strength for your application.

Hex Nuts

The most commonly used hex nuts, these are suitable for fastening most machinery and equipment.

Medium-Strength Steel

These Grade 5 or Class 8 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.

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.

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

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



	M42 × 4.5 mm	65	34	ISO Class 8	DIN 934	1	000000000	00000


	Black-Oxide Steel



			M42 × 4.5 mm	65	34	ISO Class 8	DIN 934	1	000000000	00000


			Steel



					M42 × 3 mm	65	34	ISO Class 8	DIN 934	1	000000000	00000


					M42 × 4.5 mm	65	34	ISO Class 8	DIN 934	1	000000000	0000

High-Strength Steel

Rated Grade 8, Grade C, or Class 10, these nuts are about 25% stronger than medium-strength steel nuts. They are commonly used to fasten components in valves, pumps, motors, and other high-stress applications. 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.

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

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



	M42 × 4.5 mm	65	34	ISO Class 10	DIN 934	1	000000000	000000


	Steel



			M42 × 4.5 mm	65	34	ISO Class 10	DIN 934	1	000000000	00000

Extreme-Strength Steel

These nuts are about 20% stronger than high-strength steel nuts. 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.

	Wd., mm	Ht., mm	Fastener Strength Grade/Class	Specs. Met	Pkg. Qty.		Pkg.
Steel



	M42 × 4.5 mm	65	34	ISO Class 12	DIN 934	1	000000000	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.

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	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M42 × 4.5 mm	65	34	DIN 934	1	000000000	000000


	Black-Oxide 18-8 Stainless Steel



			M42 × 4.5 mm	65	34	DIN 934	1	000000000	00000


			Highly-Corrosion-Resistant 316 Stainless Steel



					M42 × 4.5 mm	65	34	DIN 934	1	000000000	00000

Low-Strength Steel with Material Certificate

Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength nuts. They are suitable for light duty fastening applications, such as securing access panels. Use them with screws that have a similar strength rating to avoid stripping threads during installation.

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

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

	Wd., mm	Ht., mm	Specs. Met	Pkg. Qty.		Pkg.
Black-Oxide Steel



	M42 × 4.5 mm	65	34	DIN 934	1	000000000	000000


	Steel



			M42 × 4.5 mm	65	34	DIN 934	1	000000000	00000

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.

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

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



	M42 × 4.5 mm	65	21	ISO Class 04	DIN 439B, ISO 4035	1	000000000	000000


	Steel



			M42 × 1.5 mm	65	16	—	DIN 936	1	000000000	00000


			M42 × 3 mm	65	16	—	DIN 936	1	000000000	00000
			M42 × 3 mm	65	21	ISO Class 04	DIN 439B, ISO 4035	1	000000000	00000
			M42 × 4.5 mm	65	16	—	DIN 936	1	000000000	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.

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



	M42 × 4.5 mm	65	16	DIN 936	1	000000000	000000

Nylon-Insert Locknuts

Versatile yet economical, these are the most commonly used locknuts. The nylon insert grips the screw to prevent loosening from moderate vibration without damaging threads. However, the insert may become brittle if exposed to high temperatures. These locknuts are reusable a handful of times, but the holding power decreases with each use.

High-Strength Steel

Image of Product. Front orientation. Locknuts. Nylon-Insert Locknuts.

Rated Grade 8, Grade C, or Class 10, these locknuts are about 25% stronger than medium-strength steel nuts. 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.

	Wd., mm	Ht., mm	Fastener Strength Grade/Class	Insert Max. Temp., ° F	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M42 × 4.5 mm	65	42	ISO Class 10	220	DIN 985	1	000000000	000000

Medium-Strength Steel

These Grade 5 or Class 8 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.

	Wd., mm	Ht., mm	Fastener Strength Grade/Class	Insert Max. Temp., ° F	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M42 × 3 mm	65	42	ISO Class 8	220	DIN 985, ISO 10511	1	000000000	000000

Heavy-Profile Hex Nuts

About 10% wider and taller than standard-profile hex nuts, these handle heavier loads by distributing them over a larger area.

Extreme-Strength Steel

These nuts are about 20% stronger than high-strength steel nuts. 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.

	Wd., mm	Ht., mm	Fastener Strength Grade/Class	Specs. Met	Pkg. Qty.		Pkg.
Steel



	M42 × 3 mm	70	42	ASTM Grade 2H	ASTM A194	1	000000000	000000


	M42 × 4.5 mm	70	42	ASTM Grade 2H	ASTM A194	1	000000000	00000

Bearing Locknuts

Carbon Steel

With a nylon insert that grips your threaded shaft or spindle without damaging its threads, these locknuts—also called shaft nuts—hold bearings, bushings, gears, and pulleys prone to vibration tightly in place. They come as one piece, so you can easily clamp them onto your shaft or spindle. But, since they aren’t made entirely of metal, they don’t stand up to heat as well as all-metal locknuts. Slots in their sides mean you can tighten and loosen them with a spanner wrench or spanner socket. Their face is also chamfered to help keep the size and weight of your assembly at a minimum. All meet international standards for bearing locknut dimensions.

Zinc-Plated Carbon Steel—Zinc-plated carbon steel locknuts resist rusting from some moisture, but you shouldn’t use them with salt water or chemicals. They are strong and resist wear, though they don’t stand up to corrosion as well as 303 stainless steel locknuts.

Thread Spacing—When choosing your thread spacing, consider the precision of your application. The finer the threads, the more control you have when making adjustments.

	Thread					Zinc-Plated Carbon Steel
	Size	Spacing	OD, mm	Wd., mm	Insert Max. Temp., ° F		Each
Chamfered Face



		M42 × 1.5 mm	Extra Fine	62	15	210	0000000	000000

Locknuts for use with Cotter Pins

Use these locknuts to secure rotating parts subjected to mild vibration, such as the wheels on carts and hand trucks. They’re not recommended for use on parts exposed to high vibration because the pin can shear under prolonged stress. These nuts are reusable, but you'll need a new cotter pin (not included) with each use.

Medium-Strength Steel

These Grade 5 or Class 8 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.

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

	Wd., mm	Ht., mm	Fastener Strength Grade/Class	For Cotter Pin Dia., mm	Specs. Met	Pkg. Qty.		Pkg.
Steel



	M42 × 4.5 mm	65	46	ISO Class 8	8	DIN 935	1	000000000	000000

Bearing Nuts

Carbon Steel

Stepped Face

Often paired with spring lock washers to strengthen their hold, these bearing nuts—also known as shaft nuts—keep vibration from shifting bearings, bushings, pulleys, and gears on your threaded shaft or spindle. They have slotted sides, so you can tighten and loosen them with a spanner wrench or spanner socket.

Carbon Steel—Carbon steel bearing nuts are strong and resist wear.

Stepped Face—Use stepped-face bearing nuts with DIN 462 spring lock washers. You can also use them in pairs or with other bearing nuts. For the nut closer to the bearing, position the stepped face towards the bearing. All meet DIN standards for bearing lockout dimensions.

Thread Spacing—When choosing your thread spacing, consider the precision of your application. The finer the threads, the more control you have when making adjustments.

	Nuts								Bearing Lock Washers
	Thread
	Size	Spacing	OD, mm	Wd., mm	Specs. Met	For Lock Washer Specs. Met		Each		Each
Carbon Steel







				Stepped Face

				M42 × 1.5 mm	Extra Fine	62	12	DIN 1804	DIN 462	0000000	000000	000000000	00000

Thin-Profile Bearing Nuts

Used in pairs or with another bearing nut, these thin-profile nuts—often called shaft nuts—hold bearings, bushings, pulleys, and gears in place on your threaded shaft or spindle. Threading two nuts tightly against each other makes it harder for vibration to loosen your assembly than if you used only one nut. For the nut closer to the bearing, position the stepped face towards the bearing. These thin-profile nuts have holes on the side, so you can tighten and loosen them with a pin spanner wrench. All meet DIN 1816, an international standard for bearing locknut dimensions.

Carbon Steel—Carbon steel bearing nuts are strong and resist wear.

Thread Spacing—When choosing your thread spacing, consider the precision of your application. The finer the threads, the more control you have when making adjustments.

	Thread
	Size	Spacing	OD, mm	Wd., mm	Specs. Met		Each
Carbon Steel







				Stepped Face

				M42 × 1.5 mm	Extra Fine	62	12	DIN 1816	0000000	000000

T-Slot Nuts

Slide into T-slot tracks on machine tool tables to secure clamps and workpieces. These nuts are often paired with setup studs for adjustable fixtures.

Metric

Black-Oxide Steel—Create a finished look with a dark, matte coating. These nuts offer minimal corrosion resistance, so they're best for dry environments.

Fully Threaded—Fully threaded nuts allow a stud to extend beyond the bottom of the nut.

DIN 508—Nuts meet DIN dimensional and material requirements. Slide them into DIN 650 T-slots.

			Base, mm					Fully Threaded
	For Slot Wd., mm	Thread Size	Lg.	Wd.	Ht.	Overall Ht., mm	Specs. Met		Each
Black-Oxide Steel



		48	M42 × 4.5 mm	75	75	30	60	DIN 508	000000000	0000000