M28 Fasteners | McMaster-Carr

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.

	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
Chamfered Face



		M28 × 1.5 mm	Extra Fine	42	11	160	ISO 2982-2	5197N112	000000	———	0	5197N133	000000


		M28 × 1.5 mm	Extra Fine	44	11	210	—	———	0	3552N34	000000	———	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

				M28 × 1.5 mm	Extra Fine	50	10	DIN 1816	3549N21	000000

Metric Precision Lead Screws and Nuts

Pair with a motor in automated motion and positioning applications. A tight thread fit allows these lead screws and nuts to make accurate, repeatable starts and stops. Also known as single-start and self-locking lead screws and nuts, they have a single thread that runs the length of the screw. The nut travels only when the screw turns, so your system won’t unexpectedly move when the lead screw is at rest. To ensure compatibility, select components that have the same thread direction, size, and number of thread starts.

Lead Screws—Right-Hand Thread

1018 Low-Carbon Steel—Carbon steel lead screws and flanges have good machinability.

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

	Lg., mm	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn, mm	Accuracy for Travel Distance per Turn	Thread Fit	Hardness	Tensile Strength, psi	Specs. Met		Each
1018 Low-Carbon Steel



	M28 × 5 mm	1,000	Metric Trapezoidal	1:1	1	5	±0.15 mm/300 mm	Metric Trapezoidal Class 8e	Brinell 150	85,000	DIN 103	7549K83	000000


	M28 × 5 mm	1,750	Metric Trapezoidal	1:1	1	5	±0.15 mm/300 mm	Metric Trapezoidal Class 8e	Brinell 150	85,000	DIN 103	7549K84	000000

Round Nuts—Right-Hand Thread

932 Bearing Bronze—932 bearing bronze and 673 bronze nuts are wear resistant. They have good machinability and fair corrosion resistance.

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

	Lg.	Dia.	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn, mm	Thread Fit	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	Specs. Met		Each
932 Bearing Bronze



	M28 × 5 mm	2"	1.75"	Metric Trapezoidal	1:1	1	5	Metric Trapezoidal Class 7H	Brinell 69	44,000	6,100	DIN 103	7549K87	000000

Externally Threaded Nuts—Right-Hand Thread

Image of Product. Front orientation. Contains Annotated. Precision Lead Screws and Nuts. Metric Precision Lead Screws and Nuts, Externally Threaded Nuts—Right-Hand Thread.

Manganese Bronze—Manganese bronze nuts have good strength and wear resistance.

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

								External Thread
	Thread Size	Lg.	Dia.	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn, mm	Size	Lg.	Thread Fit	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	Specs. Met		Each
Manganese Bronze



		M28 × 5 mm	1 3/4"	2.125"	Metric Trapezoidal	1:1	1	5	1 31/32"-18	13/16"	Metric Trapezoidal Class 7H	Brinell 126	75,000	6,100	DIN 103	7549K94	0000000

Flange Nuts—Right-Hand Thread

Manganese Bronze—Manganese bronze nuts have good strength and wear resistance.

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

				Flange
	Thread Size	Lg.	Dia.	Dia.	Thk.	Thread Type	Speed Ratio	Bolt Circle Dia.	No. of Thread Starts	Travel Distance per Turn, mm	Thread Fit	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	No. of Mounting Holes	Specs. Met		Each
Manganese Bronze



		M28 × 5 mm	1 3/4"	2.125"	4 13/64"	53/64"	Metric Trapezoidal	1:1	3 7/16"	1	5	Metric Trapezoidal Class 7H	Brinell 126	75,000	6,100	4	DIN 103	7549K86	0000000

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

				M28 × 1.5 mm	Extra Fine	50	10	DIN 1804	DIN 462	3564N19	000000	90407A123	00000