Jam Nylocks | McMaster-Carr

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Finish

Cadmium Yellow-Chromate Plated

Corrosion-Resistant Coated

Phosphate Coated

Zinc Plated

Zinc Yellow-Chromate Plated

Width

Fastener Strength Grade/Class

Thread Type

Performance

Fastener Strength Rating

Thread Spacing

Thread Fit

Unified Standard Class 2B

Unified Standard Class 3B

DFARS Specialty Metals

Compliant

Exempt

Not Compliant

Insert Maximum Temperature

RoHS

REACH

U.S.–Mexico–Canada Agreement (USMCA) Qualifying

Yes

Export Control Classification Number (ECCN)

EAR99

Military Specification

NASM21083

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179 Products

Performance

High Strength

Withstand heavy loads and high stress without cracking

27 products

Corrosion Resistant

Won't rust in wet and outdoor environments

74 products

Specifications Met

Military Specification

Meet strict U.S. military standards for material and construction

17 products

Hex Nut Profile

Thin

Fit in spaces with low clearance

146 products

Thin-Profile Nylon-Insert Locknuts

About half the height of standard-profile locknuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against a hex nut to hold it in place. The nylon insert grips the screw to prevent loosening from moderate vibration without damaging threads. However, the insert may become brittle if exposed to high temperatures. These locknuts are reusable a handful of times, but the holding power decreases with each use.

High-Strength Steel

Rated Grade 8, Grade C, or Class 10, these locknuts are about 25% stronger than medium-strength steel nuts. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.

Zinc-Yellow-Chromate-Plated Steel—With a more durable finish than clear zinc plating, these nuts are suitable for most wet and outdoor environments. However, they won't hold up to the harsh chemicals that stainless steel can.

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

	Wd.	Ht.	Fastener Strength Grade/Class	Insert Max. Temp., ° F	Pkg. Qty.		Pkg.
Zinc-Yellow-Chromate-Plated Steel



	1/4"-20	7/16"	13/64"	SAE Grade 8	Not Rated	100	94945A205	000000


	5/16"-18	1/2"	1/4"	SAE Grade 8	Not Rated	100	94945A213	00000
	3/8"-16	9/16"	17/64"	SAE Grade 8	Not Rated	100	94945A217	00000
	3/8"-24	9/16"	17/64"	SAE Grade 8	Not Rated	50	94945A218	00000
	7/16"-14	5/8"	5/16"	SAE Grade 8	Not Rated	25	94945A260	00000
	7/16"-20	5/8"	5/16"	SAE Grade 8	Not Rated	25	94945A270	00000
	1/2"-13	3/4"	5/16"	SAE Grade 8	Not Rated	25	94945A224	00000
	5/8"-11	15/16"	25/64"	SAE Grade 8	Not Rated	10	94945A227	0000
	1 1/4"-12	1 13/16"	3/4"	SAE Grade 8	Not Rated	1	94945A280	00000
	1 1/2"-12	2 3/16"	51/64"	SAE Grade 8	Not Rated	1	94945A290	00000


	Zinc-Plated Steel



			5/16"-24	1/2"	1/4"	SAE Grade 8	220	10	94945A215	0000


			1/2"-20	3/4"	5/16"	SAE Grade 8	220	5	94945A225	0000
			5/8"-18	15/16"	25/64"	SAE Grade 8	220	5	94945A230	0000
			3/4"-16	1 1/16"	13/32"	SAE Grade 8	220	1	94945A235	0000
			7/8"-14	1 1/4"	15/32"	SAE Grade 8	220	1	94945A240	0000
			1"-14	1 7/16"	35/64"	SAE Grade 8	220	1	94945A250	0000
			1 1/8"-12	1 53/64"	41/64"	SAE Grade 8	220	1	94945A251	00000

Medium-Strength Steel

These Grade 5 or Class 8 nuts are your go-to for fastening 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.

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



	5/8"-11	15/16"	25/64"	SAE Grade 5	220	5	91342A210	000000


	5/8"-18	15/16"	25/64"	SAE Grade 5	220	5	91342A220	00000
	3/4"-10	1 1/16"	13/32"	SAE Grade 5	220	5	91342A230	00000
	3/4"-16	1 1/16"	13/32"	SAE Grade 5	220	10	91342A240	00000
	7/8"-14	1 1/4"	15/32"	SAE Grade 5	220	1	91342A250	0000
	1"-8	1 7/16"	35/64"	SAE Grade 5	220	1	91342A260	0000
	1"-14	1 7/16"	35/64"	SAE Grade 5	220	1	91342A270	0000
	1 1/8"-7	1 5/8"	41/64"	SAE Grade 5	220	1	91342A280	00000
	1 1/4"-7	1 13/16"	3/4"	SAE Grade 5	220	1	91342A290	00000
	1 1/4"-12	1 13/16"	3/4"	SAE Grade 5	220	1	91342A320	00000
	1 1/2"-6	2 3/16"	51/64"	SAE Grade 5	220	1	91342A310	00000

Low-Strength Steel

Rated Grade 2, Class 6, or lower, these locknuts 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.

Black-Zinc-Plated Steel—The dark zinc plating withstands occasional exposure to moisture while creating a finished look.

Black-Corrosion-Resistant-Coated Steel—These nuts combine a finished appearance with the rust resistance of stainless steel. The coating has been tested to extreme standards, including 1,000 hours of salt spray resistance, to hold up in wet and outdoor environments. Also known as black luster.

	Thread Size	Wd.	Ht.	Insert Max. Temp., ° F	Pkg. Qty.		Pkg.
Zinc-Plated Steel



		2-56	1/4"	7/64"	220	100	90633A004	000000


		4-40	1/4"	7/64"	220	100	90633A005	0000
		5-40	1/4"	7/64"	220	100	90633A006	0000
		6-32	5/16"	1/8"	220	100	90633A007	00000
		8-32	11/32"	11/64"	220	100	90633A009	0000
		10-24	3/8"	11/64"	220	100	90633A011	0000
		10-32	3/8"	11/64"	220	100	90633A411	0000
		12-24	7/16"	13/64"	220	100	90633A412	0000
		1/4"-20	7/16"	13/64"	220	100	90566A029	0000
		1/4"-28	7/16"	13/64"	220	100	90566A210	0000
		5/16"-18	1/2"	1/4"	220	100	90566A030	0000


		5/16"-24	1/2"	1/4"	220	100	90566A215	0000
		3/8"-16	9/16"	17/64"	220	100	90566A031	0000
		3/8"-24	9/16"	17/64"	220	100	90566A220	0000
		7/16"-14	5/8"	5/16"	220	100	90566A032	00000
		7/16"-20	5/8"	5/16"	220	100	90566A225	00000
		1/2"-13	3/4"	5/16"	220	100	90566A033	00000
		1/2"-20	3/4"	5/16"	220	100	90566A230	00000
		9/16"-12	7/8"	23/64"	220	100	90566A231	00000
		9/16"-18	7/8"	23/64"	220	100	90566A232	00000
		5/8"-11	15/16"	25/64"	220	50	90566A035	00000


		5/8"-18	15/16"	25/64"	220	50	90566A235	00000
		3/4"-10	1 1/16"	13/32"	220	10	90566A240	0000
		3/4"-16	1 1/16"	13/32"	220	10	90566A243	0000
		7/8"-9	1 1/4"	15/32"	220	5	90566A246	0000
		7/8"-14	1 1/4"	15/32"	220	5	90566A249	0000
		1"-8	1 7/16"	35/64"	220	1	90566A253	0000
		1"-14	1 7/16"	35/64"	220	1	90566A256	0000
		1 1/8"-7	1 5/8"	41/64"	220	1	90566A259	0000
		1 1/4"-7	1 13/16"	3/4"	220	1	90566A262	0000
		1 1/4"-12	1 13/16"	3/4"	220	1	90566A265	0000


		1 3/8"-6	2"	51/64"	220	1	90566A268	0000
		1 1/2"-6	2 3/16"	51/64"	220	1	90566A271	0000


		Black-Zinc-Plated Steel



				6-32	5/16"	1/8"	220	25	94627A110	0000


				8-32	11/32"	11/64"	220	25	94627A120	0000
				10-24	3/8"	11/64"	220	25	94627A130	0000
				10-32	3/8"	11/64"	220	25	94627A140	0000
				12-24	7/16"	13/64"	220	25	94627A150	0000
				1/4"-20	7/16"	13/64"	220	25	94627A160	0000
				5/16"-18	1/2"	1/4"	220	10	94627A170	0000
				3/8"-16	9/16"	17/64"	220	10	94627A180	0000


				Black-Corrosion-Resistant-Coated Steel



	6-32				5/16"	1/8"	220	5	91581A315	0000


	8-32				11/32"	11/64"	220	5	91581A325	0000
	10-24				3/8"	11/64"	220	5	91581A335	0000
	10-32				3/8"	11/64"	220	5	91581A345	0000
	1/4"-20				7/16"	13/64"	220	5	91581A355	0000
	5/16"-18				1/2"	1/4"	220	5	91581A365	0000
	3/8"-16				9/16"	17/64"	220	5	91581A375	0000
	1/2"-13				3/4"	5/16"	220	5	91581A385	0000

Corrosion-Resistant Stainless Steel

18-8 Stainless Steel—The choice for wet and outdoor environments, these locknuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

Black-Oxide 18-8 Stainless Steel—Typically chosen for their appearance, these nuts have a dark, matte coating to create a finished look. They resist rust in wet and outdoor environments, but won't hold up to the harsh chemicals that 316 stainless steel can.

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

	Thread Size	Wd.	Ht.	Insert Max. Temp., ° F	Pkg. Qty.		Pkg.
18-8 Stainless Steel



		4-40	1/4"	7/64"	220	50	90101A004	00000


		6-32	5/16"	1/8"	220	100	90101A007	00000
		8-32	11/32"	11/64"	220	100	90101A009	0000
		10-24	3/8"	11/64"	220	100	90101A011	00000
		10-32	3/8"	11/64"	220	50	90101A225	0000
		1/4"-20	7/16"	13/64"	220	50	90101A230	0000
		1/4"-28	7/16"	13/64"	220	50	90101A235	0000
		5/16"-18	1/2"	1/4"	220	50	90101A237	0000
		5/16"-24	1/2"	1/4"	220	50	90101A240	0000
		3/8"-16	9/16"	17/64"	220	25	90101A243	0000
		3/8"-24	9/16"	17/64"	220	25	90101A245	0000


		7/16"-14	5/8"	5/16"	220	10	90101A247	0000
		7/16"-20	5/8"	5/16"	220	5	90101A250	0000
		1/2"-13	3/4"	5/16"	220	10	90101A252	0000
		1/2"-20	3/4"	5/16"	220	5	90101A255	0000
		9/16"-18	7/8"	23/64"	220	1	90101A251	00000
		5/8"-11	15/16"	25/64"	220	1	90101A038	0000
		5/8"-18	15/16"	25/64"	220	1	90101A260	0000
		3/4"-10	1 1/16"	13/32"	220	1	90101A050	0000
		3/4"-16	1 1/16"	13/32"	220	1	90101A055	00000
		7/8"-9	1 1/4"	15/32"	220	1	90101A060	0000


		7/8"-14	1 1/4"	15/32"	220	1	90101A065	00000
		1"-8	1 7/16"	35/64"	220	1	90101A070	00000
		1"-14	1 7/16"	35/64"	220	1	90101A075	00000
		1 1/8"-7	1 5/8"	41/64"	220	1	90101A080	00000
		1 1/4"-7	1 13/16"	3/4"	220	1	90101A090	00000
		1 1/4"-12	1 13/16"	3/4"	220	1	90101A095	00000
		1 1/2"-6	2 3/16"	51/64"	220	1	90101A150	00000


		Black-Oxide 18-8 Stainless Steel



				4-40	1/4"	1/8"	220	100	90101A115	00000


				6-32	5/16"	9/64"	220	100	90101A116	00000
				8-32	11/32"	3/16"	220	100	90101A117	00000
				10-24	3/8"	3/16"	220	100	90101A118	00000
				10-32	3/8"	3/16"	220	100	90101A119	00000
				1/4"-20	7/16"	13/64"	220	50	90101A121	00000
				5/16"-18	1/2"	1/4"	220	50	90101A122	00000
				3/8"-16	9/16"	17/64"	220	50	90101A123	00000
				3/8"-24	9/16"	17/64"	220	50	90101A124	00000
				1/2"-13	3/4"	5/16"	220	5	90101A125	0000
				1/2"-20	3/4"	5/16"	220	5	90101A126	0000


				316 Stainless Steel



						10-24	3/8"	11/64"	220	50	97367A111	00000


10-32	3/8"					11/64"	220	50	97367A112	00000
1/4"-20	7/16"					13/64"	220	25	97367A113	0000
1/4"-28	7/16"					13/64"	220	50	97367A132	00000
5/16"-18	1/2"					1/4"	220	25	97367A114	00000
5/16"-24	1/2"					1/4"	220	50	97367A133	00000
3/8"-16	9/16"					17/64"	220	25	97367A115	00000
3/8"-24	9/16"					17/64"	220	25	97367A134	00000
7/16"-14	5/8"					5/16"	220	25	97367A135	00000
7/16"-20	5/8"					5/16"	220	25	97367A136	00000
1/2"-13	3/4"					5/16"	220	10	97367A116	00000


1/2"-20	3/4"					5/16"	220	10	97367A137	00000
3/4"-10	1 1/16"					25/64"	220	1	97367A131	00000

Thin-Heavy-Profile Nylon-Insert Locknuts

About half the height of standard-profile locknuts and 10% wider, these fit in spaces with low clearance and handle heavier loads by distributing them over a larger area. You can also use them as jam nuts by threading them against a hex nut to hold it in place. The nylon insert grips the screw to prevent loosening from moderate vibration without damaging threads. However, the insert may become brittle if exposed to high temperatures. These locknuts are reusable a handful of times, but the holding power decreases with each use.

High-Strength Steel

Black-Phosphate-Coated Steel—The dark coating creates both a finished appearance and a barrier against rust that withstands occasional exposure to moisture.

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

	Wd.	Ht.	Fastener Strength Grade/Class	Insert Max. Temp., ° F		Each
Black-Phosphate-Coated Steel



	1 1/4"-12	2"	1 7/64"	ASTM Grade C	250	93126A110	00000


	1 1/2"-12	2 3/8"	1 5/16"	ASTM Grade C	250	93126A120	00000
	1 3/4"-12	2 3/4"	1 15/32"	ASTM Grade C	250	93126A130	00000
	2"-12	3 1/8"	1 43/64"	ASTM Grade C	250	93126A140	00000
	2 1/4"-12	3 1/2"	1 15/16"	ASTM Grade C	250	93126A150	00000
	2 1/2"-12	4"	2 3/16"	ASTM Grade C	250	93126A160	00000
	2 3/4"-12	4"	2 3/16"	ASTM Grade C	250	93126A170	00000
	3"-12	4 1/2"	2 41/64"	ASTM Grade C	250	93126A210	000000


	Steel



			1 1/8"-12	1 7/8"	1"	ASTM Grade C	250	93126A180	00000


			1 3/8"-12	2 13/64"	1 3/16"	ASTM Grade C	250	93126A190	00000

Low-Strength Steel

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

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



	1/4"-20	1/2"	9/32"	250	100	90652A029	000000


	5/16"-18	9/16"	5/16"	250	100	90652A030	00000
	3/8"-16	11/16"	13/32"	250	50	90652A040	00000
	1/2"-13	7/8"	17/32"	250	25	90652A050	00000
	5/8"-11	1 1/16"	39/64"	250	10	90652A055	00000
	3/4"-10	1 1/4"	45/64"	250	10	90652A060	00000
	1"-8	1 5/8"	57/64"	250	1	90652A065	0000
	1 1/4"-7	2"	1 7/64"	250	1	90652A070	00000


	Black-Corrosion-Resistant-Coated Steel



			1/4"-20	1/2"	9/32"	250	5	90652A810	0000


			5/16"-18	9/16"	5/16"	250	5	90652A820	0000
			3/8"-16	11/16"	13/32"	250	1	90652A830	0000
			1/2"-13	7/8"	17/32"	250	1	90652A840	0000

Corrosion-Resistant Stainless Steel

18-8 Stainless Steel—The choice for wet and outdoor environments, these locknuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

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

	Wd.	Ht.	Insert Max. Temp., ° F	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	1/4"-20	1/2"	9/32"	250	25	90098A110	000000


	5/16"-18	9/16"	5/16"	250	20	90098A115	00000
	3/8"-16	11/16"	13/32"	250	10	90098A120	00000
	1/2"-13	7/8"	17/32"	250	1	90098A130	0000
	5/8"-11	1 1/16"	5/8"	250	1	90098A035	0000
	3/4"-10	1 1/4"	45/64"	250	1	90098A036	00000
	1"-8	1 5/8"	59/64"	250	1	90098A135	00000


	316 Stainless Steel



			3/8"-16	11/16"	13/32"	250	1	94530A113	0000


			1/2"-13	7/8"	17/32"	250	1	94530A115	0000
			5/8"-11	1 1/16"	39/64"	250	1	94530A117	0000
			3/4"-10	1 1/4"	45/64"	250	1	94530A119	00000

Mil. Spec. Thin-Profile Nylon-Insert Locknuts

These locknuts are manufactured and tested to strict U.S. military standards for material and construction. They are about half the height of standard-profile locknuts to fit in spaces with low clearance. You can also use them as jam nuts by threading them against a hex nut to hold it in place. The nylon insert grips the screw to prevent loosening from moderate vibration without damaging threads. However, the insert may become brittle if exposed to high temperatures. These locknuts are reusable a handful of times, but the holding power decreases with each use.

Low-Strength Steel

Cadmium Yellow-Chromate-Plated Steel—These locknuts have good lubricity to thread on smoothly and ease installation. The plating also creates a barrier against rust that's comparable to zinc-yellow-chromate plating.

	Wd.	Ht.	Mil. Spec.	Insert Max. Temp., ° F	Pkg. Qty.		Pkg.
Cadmium Yellow-Chromate-Plated Steel



	4-40	1/4"	1/8"	MS21083N04, NASM21083	250	10	95496A310	000000


	6-32	5/16"	9/64"	MS21083N06, NASM21083	250	10	95496A320	00000
	8-32	11/32"	3/16"	MS21083N08, NASM21083	250	10	95496A330	0000
	10-32	3/8"	3/16"	MS21083N3, NASM21083	250	10	95496A340	0000
	1/4"-28	7/16"	7/32"	MS21083N4, NASM21083	250	10	95496A350	0000
	1/2"-20	3/4"	5/16"	MS21083N8, NASM21083	250	1	95496A380	0000

Corrosion-Resistant Stainless Steel

18-8 Stainless Steel—The choice for wet and outdoor environments, these locknuts resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

	Wd.	Ht.	Mil. Spec.	Insert Max. Temp., ° F	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	2-56	1/4"	7/64"	MS21083C02, NASM21083	250	5	97231A480	000000


	4-40	1/4"	1/8"	MS21083C04, NASM21083	250	10	97231A410	00000
	6-32	5/16"	9/64"	MS21083C06, NASM21083	250	10	97231A420	00000
	8-32	11/32"	3/16"	MS21083C08, NASM21083	250	5	97231A430	0000
	10-32	3/8"	3/16"	MS21083C3, NASM21083	250	5	97231A440	00000
	1/4"-28	7/16"	7/32"	MS21083C4, NASM21083	250	5	97231A450	00000
	5/16"-24	1/2"	17/64"	MS21083C5, NASM21083	250	1	97231A460	0000
	3/8"-24	9/16"	9/32"	MS21083C6, NASM21083	250	1	97231A470	0000
	7/16"-20	11/16"	21/64"	MS21083C7, NASM21083	250	1	97231A510	00000
	1/2"-20	3/4"	5/16"	MS21083C8, NASM21083	250	1	97231A490	00000
	5/8"-18	15/16"	13/32"	MS21083C10, NASM21083	250	1	97231A520	00000