Nylon Acorn Nuts | McMaster-Carr

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42 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.

Plastic

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

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


	4-40	1/4"	9/32"	-40 to 185	Black , Off-White	100	000000000	000000
	6-32	19/64"	11/32"	-40 to 185	Black , Off-White	100	000000000	00000
	8-32	21/64"	3/8"	-40 to 185	Black , Off-White	100	000000000	00000
	10-24	23/64"	13/32"	-40 to 185	Black , Off-White	100	000000000	00000
	10-32	23/64"	13/32"	-40 to 185	Black , Off-White	100	000000000	00000
	1/4"-20	27/64"	15/32"	-40 to 185	Black , Off-White	100	000000000	00000
	1/4"-28	27/64"	15/32"	-40 to 185	Black , Off-White	100	000000000	00000
	5/16"-18	1/2"	17/32"	-40 to 185	Black , Off-White	50	000000000	00000
	5/16"-24	1/2"	17/32"	-40 to 185	Black , Off-White	50	000000000	00000
	3/8"-16	9/16"	5/8"	-40 to 185	Black , Off-White	25	000000000	00000
	3/8"-24	9/16"	5/8"	-40 to 185	Black , Off-White	25	000000000	00000
	7/16"-14	3/4"	13/16"	-40 to 185	Black , Off-White	10	000000000	0000
	1/2"-13	3/4"	13/16"	-40 to 185	Black , Off-White	25	000000000	00000
	1/2"-20	3/4"	13/16"	-40 to 185	Black , Off-White	10	000000000	0000
	5/8"-11	15/16"	31/32"	-40 to 185	Black , Off-White	20	000000000	00000
	M4 × 0.7 mm	7 mm	8 mm	-40 to 185	Black , Off-White	100	000000000	00000
	M5 × 0.8 mm	8 mm	10 mm	-40 to 185	Black , Off-White	100	000000000	00000
	M6 × 1 mm	10 mm	12 mm	-40 to 185	Black , Off-White	100	000000000	00000
	M8 × 1.25 mm	13 mm	15 mm	-40 to 185	Black , Off-White	50	000000000	00000
	M10 × 1.5 mm	17 mm	18 mm	-40 to 185	Black , Off-White	25	000000000	00000
	M12 × 1.75 mm	19 mm	20.5 mm	-40 to 185	Black , Off-White	25	000000000	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

Image of Product. Front orientation. Cap Nuts. Nylon-Insert Cap Nuts.

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.

Steel—Best for dry environments since moisture will cause these nuts to rust.

Nylon 6/6 Cap—The nylon cap on these nuts is softer than metal, so it's less likely to scratch surrounding surfaces or parts.

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


		M4 × 0.7 mm	2.3 mm	7 mm	9.6 mm	ISO Class 6	DIN 986	245	50	000000000	000000
		M5 × 0.8 mm	3.5 mm	8 mm	10.5 mm	ISO Class 6	DIN 986	245	25	000000000	0000
		M6 × 1 mm	3.9 mm	10 mm	12 mm	ISO Class 6	DIN 986	245	25	000000000	0000
		M8 × 1.25 mm	5.2 mm	13 mm	14 mm	ISO Class 6	DIN 986	245	25	000000000	00000
		M10 × 1.5 mm	6.4 mm	16 mm	18 mm	ISO Class 6	DIN 986	245	10	000000000	0000
		M12 × 1.75 mm	8.3 mm	18 mm	23 mm	ISO Class 6	DIN 986	245	5	000000000	0000
		M16 × 2 mm	11.3 mm	24 mm	28 mm	ISO Class 6	DIN 986	245	1	000000000	0000
		M20 × 2.5 mm	13.5 mm	30 mm	35 mm	ISO Class 6	DIN 986	245	1	000000000	0000

		Zinc-Plated Steel with Nylon 6/6 Cap


				8-32	9/64"	11/32"	23/64"	SAE Grade 2	__	250	25	000000000	0000
				10-24	9/64"	3/8"	23/64"	SAE Grade 2	__	250	25	000000000	0000
				10-32	9/64"	3/8"	23/64"	SAE Grade 2	__	250	25	000000000	0000
				1/4"-20	7/32"	7/16"	31/64"	SAE Grade 2	__	250	25	000000000	0000
				5/16"-18	1/4"	1/2"	1/2"	SAE Grade 2	__	250	10	000000000	0000
				3/8"-16	21/64"	9/16"	5/8"	SAE Grade 2	__	250	25	000000000	00000

				Steel with Nylon 6/6 Cap


						8-32	9/64"	11/32"	23/64"	SAE Grade 2	__	250	25	000000000	0000
						10-32	9/64"	3/8"	23/64"	SAE Grade 2	__	250	25	000000000	0000
						1/4"-20	7/32"	7/16"	31/64"	SAE Grade 2	__	250	25	000000000	0000
						1/4"-28	7/32"	7/16"	31/64"	SAE Grade 2	__	250	25	000000000	0000
						5/16"-24	1/4"	1/2"	1/2"	SAE Grade 2	__	250	25	000000000	0000
						3/8"-24	21/64"	9/16"	5/8"	SAE Grade 2	__	250	25	000000000	00000

Medium-Strength Steel

About twice as strong as low-strength steel, these Grade 5 nuts fasten 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.

Nylon 6/6 Cap—The nylon cap on these nuts is softer than metal, so it's less likely to scratch surrounding surfaces or parts.

	Thread
	Size	Dp.	Wd.	Ht.	Fastener Strength Grade/Class	Insert Max. Temp., ° F	Pkg. Qty.		Pkg.
Zinc-Plated Steel with Nylon 6/6 Cap


		3/8"-24	21/64"	9/16"	5/8"	SAE Grade 5	250	10	000000000	000000