M6 Cap Nuts | McMaster-Carr

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Help me decide (beta)

10 Products

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Performance

Corrosion Resistant

Won't rust in wet and outdoor environments

5 products

Vibration Resistant

Grip tighter than other nuts to resist loosening due to vibration

2 products

Performance

High Strength

Withstand heavy loads and high stress without cracking

1 product

Application

Sealing

Keep out liquid, debris, and other contaminants

1 product

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

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.

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

	Thread Dp., mm	Wd., mm	Ht., mm	Certificate Type	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M6 × 1 mm	7.7	10	12	Material Certificate	20	94000A038	00000


	Highly Corrosion-Resistant 316 Stainless Steel



			M6 × 1 mm	8	10	12	Material Certificate	25	95514A104	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.

	Thread Dp., mm	Wd., mm	Ht., mm	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M6 × 1 mm	7.7	10	12	50	91880A045	000000


	Chrome-Plated Steel



			M6 × 1 mm	5.7	10	12	5	91982A250	00000

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.

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



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

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.

	Wd., mm	Ht., mm	Temp. Range, ° F	Choose a Color	Pkg. Qty.		Pkg.
Nylon 6/6



	M6 × 1 mm	10	12	-40 to 185	Black, Off-White	100	90527A515	000000

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.

	Thread Dp., mm	Wd., mm	Ht., mm	Pkg. Qty.		Pkg.
Brass



	M6 × 1 mm	8	10	12	5	92716A115	000000

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

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.

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

Stainless Steel

Image of Product. Front orientation. Contains Annotated, Border. Cap Nuts. Cap Nuts with Threadlocker.

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	Certificate Type	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M6 × 1 mm	5.7	10	12	Material Certificate	5	90428A120	000000

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	Insert Max. Temp., ° F	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M6 × 1 mm	3.9	10	12	Class 6	245	25	90582A113	00000