M45 Nuts | McMaster-Carr

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.

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.
Black-Oxide Steel



	M45 × 4.5 mm	70	36	Class 8	DIN 934	1	90593A022	000000


	Steel



			M45 × 3 mm	70	36	Class 8	DIN 934	1	91423A380	00000


			M45 × 4.5 mm	70	36	Class 8	DIN 934	1	90592A495	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



	M45 × 4.5 mm	70	36	Class 12	DIN 934	1	94223A116	000000

Shock Absorber Mounting Nuts

Round Nuts

Use Mounting Blocks for Shock Absorbers (not included) to mount and secure threaded-body shock absorbers.

		Steel
	Thread Size		Each
Round Nuts



		M45 × 1.5 mm	6600K79	000000

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.

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



	M45 × 3 mm	70	22.5	Class 04	DIN 439B, ISO 8675	1	90326A227	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.

Medium-Strength Steel

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

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



	M45 × 3 mm	70	45	Class 8	185	DIN 985, ISO 10511	1	90576A544	000000

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.

Carbon Steel—All carbon steel locknuts are strong and resist wear, though they don’t stand up to corrosion as well as 303 stainless steel locknuts.

303 Stainless Steel—303 stainless steel locknuts resist corrosion better than carbon steel locknuts but aren’t as strong. They withstand washdowns and chemicals.

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.

	Locknuts												Sockets
	Thread						Carbon Steel		Zinc-Plated Carbon Steel		303 Stainless Steel
	Size	Spacing	OD, mm	Wd., mm	Insert Max. Temp., ° F	Specs. Met		Each		Each		Each		Each
Chamfered Face



		M45 × 1.5 mm	Extra Fine	62	12	210	—	———	0	3552N43	000000	———	0	———	0


		M45 × 1.5 mm	Extra Fine	65	13	160	ISO 2982-2	5197N115	000000	———	0	5197N136	000000	5510N157	0000000

Bearing Nuts

Carbon Steel

Chamfered Face

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.

Chamfered Face—Chamfered-face bearing nuts weigh less and produce less heat than stepped-face nuts.

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.

ISO 2982— Some chamfered-face bearing nuts meet ISO 2982 (formerly DIN 981), an international standard for bearing locknut dimensions. Their sizes correspond to SKF KM series. Use them with DIN 5406 spring lock washers.

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







				Chamfered Face

				M45 × 1.5 mm	Extra Fine	65	10	DIN 981, ISO 2982	DIN 5406	3554N21	00000	90391A121	00000




						Stepped Face

						M45 × 1.5 mm	Extra Fine	68	12	DIN 1804	DIN 462	3564N27	00000	90407A131	0000

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.

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

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	Certificate Type	Pkg. Qty.		Pkg.
Steel



	M45 × 4.5 mm	75	45	ASTM Grade 2H	ASTM A194	Material Certificate	1	98498A211	000000

Spanner Sockets


Socket Shown With Wrench (Sold Separately)

4-Pin

For easy tightening and loosening, these sockets have pins that grip the slotted sides on bearing nuts. These sockets require less clearance around bearings than standard hook spanner wrenches, so they’re good in tight spaces. Use them with a square-drive wrench handle or a ratchet wrench; they’re not for use with impact wrenches.

	For Nut Thread Size	For Bearing Nut Specs. Met	For Nut Dia., mm	Bolt Clearance Dp., mm	Material		Each
4-Pin Socket







	1/2" Square Drive

	65	90	81	M45	ISO 2982-2	65	57	Steel	5510N157	0000000

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

				M45 × 1.5 mm	Extra Fine	68	12	DIN 1816	3549N26	000000