M20 Bearing Nuts | McMaster-Carr

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160° F

210° F

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1,000 lb. to 1,999 lb.

2,000 lb. to 9,999 lb.

10,000 lb. to 19,999 lb.

20,000 lb. or greater

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25 Products

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



		M20 × 1 mm	Extra Fine	32	9.5	210	—	———	0	3552N26	000000	———	0	———	0


		M20 × 1 mm	Extra Fine	32	10	160	ISO 2982-2	6343K35	000000	———	0	6343K97	000000	5510N148	0000000
		M20 × 1.5 mm	Extra Fine	32	9.5	210	—	———	0	3552N27	00000	———	0	———	0

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







				Chamfered Face

				M20 × 1 mm	Extra Fine	32	6	DIN 981, ISO 2982	DIN 5406	3554N15	00000	90391A115	00000	5510N179	0000000




						Stepped Face

						M20 × 1.5 mm	Extra Fine	36	8	DIN 1804	DIN 462	3564N16	00000	90407A118	0000	———	0

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

				M20 × 1.5 mm	Extra Fine	36	8	DIN 1816	3549N16	000000

Ball Screws and Nuts


	Ball Nuts Flange Nut Style C

Internal ball bearings provide smooth low-friction travel in applications that require high speeds, accurate positioning, and repeatable movement. Also known as single-start ball screws and nuts, they have a single thread that runs the length of the screw. They operate with more torque than fast-travel ball screws and nuts. To ensure compatibility, select components that have the same thread direction and size. Ball nuts are furnished with a tube to keep ball bearings in place. Do not remove the tube until you are ready to install the nuts onto the screws.

Ball Screws—Right-Hand Threaded

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a ball nut moves with one revolution of the ball screw.

Root Diameter—Root diameter indicates the diameter the ball screw will be after machining away the threads.

	Lg., mm	No. of Thread Starts	Travel Distance per Turn, mm	Accuracy for Travel Distance per Turn	Root Dia., mm	Hardness	Tensile Strength, psi	Temp. Range, ° F		Each
Carbon Steel



	M20	500	1	5	±0.210 mm/300 mm	17.2	Rockwell C58	21,000	5 to 175	6624K64	0000000


	M20	1,000	1	5	±0.210 mm/300 mm	17.2	Rockwell C58	21,000	5 to 175	6624K4	000000
	M20	1,500	1	10	±0.210 mm/300 mm	16.4	Rockwell C58	21,000	5 to 175	6624K8	000000

Platform Ball Nuts—Right-Hand Threaded

Image of Product. Front orientation. Contains Annotated. Ball Screws and Nuts. Ball Screws and Nuts , Platform Nut, Ball Nuts.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a ball nut moves with one revolution of the ball screw.

	Lg., mm	Wd., mm	Ht., mm	Ctr. Ht., mm	No. of Thread Starts	Travel Distance per Turn, mm	Hardness	Dynamic Thrust Load Cap., lb.	Max. Backlash, mm	Temp. Range, ° F		Each
Alloy Steel



	M20	35	48	39	17	1	5	Rockwell C58	1,300	0.1	5 to 175	6624K29	0000000


	M20	58	48	46	18	1	10	Rockwell C58	2,350	0.1	5 to 175	6624K31	000000

Flange Ball Nuts—Right-Hand Threaded

Style C

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a ball nut moves with one revolution of the ball screw.

					Flange, mm
	Style	Thread Size	Lg., mm	Dia., mm	Wd.	Ht.	Thk.	No. of Thread Starts	Travel Distance per Turn, mm	Hardness	Dynamic Thrust Load Cap., lb.	Max. Backlash, mm	Temp. Range, ° F		Each
Alloy Steel



		C	M20	40	40	60	46	10	1	5	Rockwell C58	1,300	0.1	5 to 175	6624K43	0000000


		C	M20	64	52	82	64	12	1	10	Rockwell C58	2,350	0.1	5 to 175	6624K44	000000

Roller Screws and Nuts

Precision ground to create more points of contact, these roller screws and nuts are highly accurate and handle much higher loads than ball screws and nuts of the same size. They're most traditionally used to replace hydraulics in linear actuators but can also be used in place of ball and lead screw assemblies because of their high load capacity and precise motion control. In fact, they're almost four times more accurate than our most accurate ball and lead screws. They also last longer than ball screw nuts in systems with lower loads and can handle higher shock loads. However, because they have more contact points, they’re slightly less efficient than ball screws. To ensure compatibility, select components that have the same thread direction and size.

Roller Screws—Right-Hand Partially Threaded

Roller screws are made of hardened steel for strength and durability.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a roller nut moves with one revolution of the roller screw.

	Lg., mm	No. of Thread Starts	Travel Distance per Turn, mm	Accuracy for Travel Distance per Turn	Min. Thread Lg., mm	Root Dia., mm	Hardness	Tensile Strength, psi		Each
Alloy Steel



	M20	680	5	4	±0.023 mm/300 mm	561	19.15	Rockwell C60	105,000	4543N13	000000000


	M20	680	5	5	±0.023 mm/300 mm	561	19.05	Rockwell C60	105,000	4543N14	00000000

Round Nuts—Right-Hand Thread

Image of Product. Front orientation. Roller Screws and Nuts. Nuts.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a roller nut moves with one revolution of the roller screw.

						Keyway, mm
	Thread Size	Lg., mm	Dia., mm	No. of Thread Starts	Travel Distance per Turn, mm	Wd.	Dp.	Hardness	Dynamic Thrust Load Cap., lb.	Max. Backlash, mm	Temp. Range, ° F	Lubrication		Each
Alloy Steel



		M20	65	42	5	4	4	18	Rockwell C60	15,100	0.03	-40 to 350	Required	4543N17	000000000


		M20	65	42	5	5	4	18	Rockwell C60	20,600	0.03	-40 to 350	Required	4543N18	00000000

Fast-Travel Ball Screws and Nuts


	Ball Nuts Flange Nut Style E

Multiple thread channels (also known as thread starts) create faster linear travel than ball screws with a single thread start. Internal ball bearings provide smooth low-friction travel in applications that require high speeds, accurate positioning, and repeatable movement. To ensure compatibility, select components that have the same thread size and number of thread starts. Ball nuts are furnished with a tube to keep ball bearings in place. Do not remove the tube until you are ready to install the nuts onto the screws.

Ball Screws—Right-Hand Threaded

Carbon Steel—Carbon steel ball screws and nuts are case hardened, so they resist wear better than standard carbon steel. However, they are less corrosion resistant than black-oxide alloy steel screws and nuts.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a ball nut moves with one revolution of the ball screw.

Root Diameter—Root diameter indicates the diameter the ball screw will be after machining away the threads.

	Lg., mm	No. of Thread Starts	Travel Distance per Turn, mm	Accuracy for Travel Distance per Turn	Root Dia., mm	Hardness	Tensile Strength, psi	Temp. Range, ° F		Each
Carbon Steel



	M20	500	4	20	±0.05 mm/300 mm	17	Rockwell C56	95,000	32 to 150	4566N161	0000000


	M20	1,000	4	20	±0.05 mm/300 mm	17	Rockwell C56	95,000	32 to 150	4566N162	000000

Flange Ball Nuts—Right-Hand Threaded

Style E

Image of Attribute. Front orientation. Contains Annotated. Fast-Travel Ball Screws and Nuts.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a ball nut moves with one revolution of the ball screw.

					Flange, mm
	Style	Thread Size	Lg., mm	Dia., mm	Dia.	Thk.	No. of Thread Starts	Travel Distance per Turn, mm	Bolt Circle Dia., mm	Hardness	Dynamic Thrust Load Cap., lb.	Max. Backlash, mm	Temp. Range, ° F		Each
Carbon Steel



		E	M20	77	35	58	10	4	20	47	Rockwell C56	2,750	0.04	32 to 150	4566N404	0000000