Metric Cap Nuts | McMaster-Carr

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DFARS Specialty Metals

Environment

69 Products

Performance

Corrosion Resistant

Won't rust in wet and outdoor environments

39 products

Vibration Resistant

Grip tighter than other nuts to resist loosening due to vibration

13 products

Performance

High Strength

Withstand heavy loads and high stress without cracking

4 products

Application

Sealing

Keep out liquid, debris, and other contaminants

5 products

Cap Nuts

Conceal and protect protruding screw threads while fastening parts together. These nuts help prevent damage to surrounding materials and reduce injuries. Also known as acorn nuts, they have a smooth, rounded head that creates a finished look.

Stainless Steel

Image of Product. Front orientation. Cap Nuts. Cap Nuts.

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.

Highly Corrosion-Resistant 316 Stainless Steel—Our most corrosion-resistant cap nuts, these hold up in just about any environment. They won't degrade from exposure to weather, salt water, and most chemicals.

								Pkg.
	Thread Size	Thread Dp., mm	Wd., mm	Ht., mm	Specs. Met	Pkg. Qty.		1-9	10-49	50-Up
18-8 Stainless Steel



		M3 × 0.5 mm	3.8	5.5	6	DIN 1587	10	94000A330	00000	00000	00000


		M4 × 0.7 mm	5.7	7	8	DIN 1587	25	94000A035	0000	0000	0000
		M5 × 0.8 mm	4.5	8	10	DIN 1587	25	94000A037	0000	0000	0000
		M6 × 1 mm	7.7	10	12	DIN 1587	20	94000A038	0000	0000	0000
		M8 × 1.25 mm	10.7	13	15	DIN 1587	10	94000A039	0000	0000	0000
		M10 × 1.5 mm	12.7	17	18	DIN 1587	5	94000A040	0000	0000	0000
		M12 × 1.75 mm	15.7	19	22	DIN 1587	5	94000A041	0000	0000	0000
		M14 × 2 mm	17.7	22	25	DIN 1587	1	94000A431	0000	0000	0000
		M16 × 2 mm	20.6	24	28	DIN 1587	1	94000A461	0000	0000	0000
		M18 × 2.5 mm	24.6	27	32	DIN 1587	1	94000A490	0000	0000	0000
		M20 × 2.5 mm	25.6	30	34	DIN 1587	1	94000A510	0000	0000	0000


		M22 × 2.5 mm	28.6	34	39	DIN 1587	1	94000A101	0000	0000	0000
		M24 × 3 mm	30.5	36	42	DIN 1587	1	94000A102	0000	0000	0000


		Highly Corrosion-Resistant 316 Stainless Steel



				M3 × 0.5 mm	3.8	5.5	6	DIN 1587	25	95514A101	0000	0000	0000


				M4 × 0.7 mm	5.5	7	8	DIN 1587	25	95514A102	0000	0000	0000
				M5 × 0.8 mm	4.5	8	10	DIN 1587	25	95514A103	0000	0000	0000
				M6 × 1 mm	8	10	12	DIN 1587	25	95514A104	00000	00000	0000
				M8 × 1.25 mm	11	13	15	DIN 1587	10	95514A105	0000	0000	0000
				M10 × 1.5 mm	13	17	18	DIN 1587	10	95514A106	00000	00000	00000
				M12 × 1.75 mm	16	19	22	DIN 1587	5	95514A107	00000	00000	00000
				M14 × 2 mm	18	22	25	DIN 1587	1	95514A108	0000	0000	0000
				M16 × 2 mm	21	24	28	DIN 1587	1	95514A109	0000	0000	0000
				M20 × 2.5 mm	26	30	34	DIN 1587	1	95514A111	00000	00000	00000
				M22 × 2.5 mm	29	34	39	DIN 1587	1	95514A112	00000	00000	00000


				M24 × 3 mm	31	36	42	DIN 1587	1	95514A113	00000	00000	00000

Low-Strength Steel

Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength steel 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.

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

Chrome-Plated Steel—The brightest, shiniest finish we offer, this plating has a mirror-like appearance that is often used in decorative applications. It resists salt water and chemicals better than zinc plating and is less likely to wear off.

								Pkg.
	Thread Size	Thread Dp., mm	Wd., mm	Ht., mm	Specs. Met	Pkg. Qty.		1-9	10-49	50-Up
Zinc-Plated Steel



		M4 × 0.7 mm	5.3	7	8	DIN 1587	50	91880A035	000000	000000	000000


		M5 × 0.8 mm	3.7	8	10	DIN 1587	50	91880A037	00000	00000	00000
		M6 × 1 mm	7.7	10	12	DIN 1587	50	91880A045	00000	00000	00000
		M8 × 1.25 mm	10.7	13	15	DIN 1587	25	91880A050	00000	00000	00000
		M10 × 1.5 mm	12.7	17	18	DIN 1587	10	91880A056	00000	0000	0000
		M12 × 1.75 mm	15.7	19	22	DIN 1587	10	91880A060	00000	00000	00000


		Chrome-Plated Steel



				M4 × 0.7 mm	3.9	7	8	DIN 1587	5	91982A200	00000	00000	0000


				M5 × 0.8 mm	5.6	8	10	DIN 1587	5	91982A225	00000	00000	0000
				M6 × 1 mm	5.7	10	12	DIN 1587	5	91982A250	00000	00000	00000
				M8 × 1.25 mm	8.2	13	15	DIN 1587	1	91982A275	0000	0000	0000
				M10 × 1.5 mm	9.7	17	18	DIN 1587	1	91982A300	0000	0000	0000
				M12 × 1.75 mm	12.2	19	22	DIN 1587	1	91982A325	0000	0000	0000

High-Strength Steel

Rated Grade 8 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.

									Pkg.
	Thread Size	Thread Dp., mm	Wd., mm	Ht., mm	Fastener Strength Grade/Class	Specs. Met	Pkg. Qty.		1-9	10-49	50-Up
Zinc-Plated Steel



		M6 × 1 mm	5.7	10	12	Class 10	DIN 1587	5	99164A101	000000	000000	000000


		M8 × 1.25 mm	8.2	13	15	Class 10	DIN 1587	5	99164A102	00000	00000	00000
		M10 × 1.5 mm	9.7	17	18	Class 10	DIN 1587	1	99164A103	0000	0000	0000
		M12 × 1.75 mm	12.2	19	22	Class 10	DIN 1587	1	99164A104	00000	0000	0000

Plastic

Nylon 6/6—Slippery and abrasion resistant, these nuts thread on smoothly and stand up to daily wear and tear. Nylon will swell and weaken when exposed to moisture, so it's best for dry environments.

								Pkg.
	Thread Size	Wd., mm	Ht., mm	Temp. Range, ° F	Choose a Color	Pkg. Qty.		1-9	10-49	50-Up
Nylon 6/6



		M4 × 0.7 mm	7	8	-40 to 185	Black, Off-White	100	90527A505	000000	000000	000000


		M5 × 0.8 mm	8	10	-40 to 185	Black, Off-White	100	90527A510	00000	00000	00000
		M6 × 1 mm	10	12	-40 to 185	Black, Off-White	100	90527A515	00000	00000	00000
		M8 × 1.25 mm	13	15	-40 to 185	Black, Off-White	50	90527A520	00000	00000	00000
		M10 × 1.5 mm	17	18	-40 to 185	Black, Off-White	25	90527A525	00000	00000	00000
		M12 × 1.75 mm	19	20.5	-40 to 185	Black, Off-White	25	90527A530	00000	00000	00000

Brass

Brass—Conductive and nonmagnetic, brass nuts are commonly used to secure electrical equipment, such as circuit board assemblies and mounting brackets, inside enclosures. They're also softer than most metals, so they won't damage other fastening components.

							Pkg.
	Thread Size	Thread Dp., mm	Wd., mm	Ht., mm	Pkg. Qty.		1-9	10-49	50-Up
Brass



		M4 × 0.7 mm	5.5	7	8	5	92716A114	00000	00000	00000


		M6 × 1 mm	8	10	12	5	92716A115	00000	00000	00000
		M8 × 1.25 mm	11	13	15	5	92716A116	0000	0000	0000
		M10 × 1.5 mm	13	17	18	1	92716A117	00000	00000	00000

Sanitary Cap Nuts

With extremely smooth sides and rounded edges, these nuts are free of crevices where bacteria can grow. Use them to cover and protect exposed threads while fastening parts together. Nuts are certified by EHEDG to meet sanitary design standards. They have a Buna-N seal on the base that keeps liquid, debris, and other contaminants off the threads. The seal is made with metal and chemical additives, so you can find it with a metal detector or X-ray machine if it falls into your line. Also known as acorn nuts, these have a domed head to create a finished look.

Stainless Steel

Image of Product. Front orientation. Cap Nuts. Sanitary Cap Nuts.

Highly Corrosion-Resistant 316 Stainless Steel—Won't corrode from frequent washdowns and can stand up to the harshest cleaners and detergents.

	Thread Dp., mm	Wd., mm	Ht., mm	Seal Material	Certification	Food Industry Std.		Each
Highly Corrosion-Resistant 316 Stainless Steel



	M6 × 1 mm	5.5	10	8	Buna-N	EHEDG Certified	FDA Compliant 21 CFR 177.2600	97511A110	000000


	M8 × 1.25 mm	6.5	13	10	Buna-N	EHEDG Certified	FDA Compliant 21 CFR 177.2600	97511A120	00000
	M10 × 1.5 mm	8	16	12	Buna-N	EHEDG Certified	FDA Compliant 21 CFR 177.2600	97511A130	00000
	M12 × 1.75 mm	9	18	14	Buna-N	EHEDG Certified	FDA Compliant 21 CFR 177.2600	97511A140	00000
	M16 × 2 mm	10.5	24	17	Buna-N	EHEDG Certified	FDA Compliant 21 CFR 177.2600	97511A150	00000

Nylon-Insert Cap Nuts

Get the protection of a cap nut with the vibration resistance of a locknut. These nuts not only conceal protruding screw threads, they also have a nylon insert that grips the screw to prevent loosening from moderate vibration. However, the insert may become brittle if exposed to high temperatures. Nuts are reusable a handful of times, but their holding power decreases with each use.

Low-Strength Steel

Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength steel nuts. Use them with screws that have a similar 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.

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



	M4 × 0.7 mm	2.3	7	9.6	Class 6	DIN 986	245	50	90582A111	000000


	M5 × 0.8 mm	3.5	8	10.5	Class 6	DIN 986	245	25	90582A112	0000
	M6 × 1 mm	3.9	10	12	Class 6	DIN 986	245	25	90582A113	0000
	M8 × 1.25 mm	5.2	13	14	Class 6	DIN 986	245	25	90582A114	00000
	M10 × 1.5 mm	6.4	16	18	Class 6	DIN 986	245	10	90582A115	00000
	M12 × 1.75 mm	8.3	18	23	Class 6	DIN 986	245	5	90582A116	0000
	M16 × 2 mm	11.3	24	28	Class 6	DIN 986	245	1	90582A117	0000
	M20 × 2.5 mm	13.5	30	35	Class 6	DIN 986	245	1	90582A118	0000

Cap Nuts with Threadlocker

These nuts not only conceal and protect protruding screw threads, they also resist loosening from mild vibration. They have a nylon patch bonded to their threads that grips screws for a tighter hold than standard cap nuts. They’re reusable a handful of times, but the patch’s holding power decreases with each use. Also known as acorn nuts, they have a smooth, rounded head that creates a finished look.

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.

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



	M5 × 0.8 mm	5.6	8	10	DIN 1587	5	90428A110	000000


	M6 × 1 mm	5.7	10	12	DIN 1587	5	90428A120	00000
	M8 × 1.25 mm	8.2	13	15	DIN 1587	5	90428A130	00000
	M10 × 1.5 mm	9.7	17	18	DIN 1587	1	90428A140	00000
	M12 × 1.75 mm	12.2	19	22	DIN 1587	1	90428A150	00000