Machine Screw Square Nuts

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160 Products

Low-Strength Steel Square Nuts

Large flat sides make these nuts easy to grip with a wrench and keep them from rotating in channels and square holes. About half the strength of medium-strength steel square nuts, use them in light duty fastening applications, such as securing access panels.

Zinc-Plated Steel—Zinc-plated steel square nuts resist corrosion in wet environments.

Black-Zinc-Plated Steel—Black-zinc-plated steel square nuts resist corrosion in wet environments and have a black finish that blends in with dark surfaces.

Hot-Dipped Galvanized Steel—Hot-dipped galvanized steel square nuts have a thick coating for better corrosion resistance than zinc-plated steel nuts. They must be used with other hot-dipped galvanized fasteners.

Steel—Steel square nuts are best for dry environments, since moisture will cause them to rust.

	Thread Size	Wd.	Ht.	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Plated Steel



		2-56	3/16"	1/16"	—	100	94855A279	00000
		4-40	1/4"	3/32"	—	100	94855A281	0000
		5-40	5/16"	7/64"	—	100	94855A282	0000
		6-32	5/16"	7/64"	—	100	94855A201	0000
		8-32	11/32"	1/8"	—	100	94855A216	0000
		10-24	3/8"	1/8"	—	100	94855A232	0000
		10-32	3/8"	1/8"	—	100	94855A283	0000
		1/4"-20	7/16"	3/16"	—	100	94855A247	0000
		1/4"-28	7/16"	3/16"	—	100	94855A284	00000
		5/16"-18	9/16"	7/32"	—	100	94855A263	00000


		3/8"-16	5/8"	1/4"	—	50	94855A278	00000
		1/2"-13	13/16"	7/16"	—	25	94855A285	0000
		5/8"-11	1"	35/64"	—	25	94855A286	00000
		3/4"-10	1 1/8"	21/32"	—	10	94855A287	0000
		1"-8	1 1/2"	7/8"	—	5	94855A288	00000


		Black-Zinc-Plated Steel



				1/4"-20	7/16"	3/16"	—	100	94859A111	00000
				5/16"-18	9/16"	7/32"	—	50	94859A122	00000
				3/8"-16	5/8"	1/4"	—	50	94859A133	00000


				Hot-Dipped Galvanized Steel



						5/16"-18	9/16"	17/64"	—	100	93430A410	00000
						3/8"-16	5/8"	21/64"	—	100	93430A415	00000
						1/2"-13	13/16"	7/16"	—	50	93430A421	00000
						5/8"-11	1"	35/64"	—	25	93430A425	00000
						3/4"-10	1 1/8"	21/32"	—	10	93430A430	0000
						7/8"-9	1 5/16"	49/64"	—	5	93430A435	0000
						1"-8	1 1/2"	7/8"	—	5	93430A440	00000


						Steel



								6-32	5/16"	7/64"	—	100	94855A115	0000
								8-32	11/32"	1/8"	—	100	94855A119	0000
								10-24	3/8"	1/8"	—	100	94855A123	0000
								10-32	3/8"	1/8"	—	100	94855A136	0000
								1/4"-20	7/16"	3/16"	—	100	94855A127	00000
								1/4"-20	7/16"	7/32"	—	100	90043A029	0000
								5/16"-18	9/16"	7/32"	—	100	94855A131	00000
								5/16"-18	9/16"	17/64"	—	100	90043A030	00000
								3/8"-16	5/8"	1/4"	—	100	94855A135	00000
								3/8"-16	5/8"	21/64"	—	100	90043A031	00000


								7/16"-14	3/4"	3/8"	—	25	90043A034	00000
								1/2"-13	13/16"	7/16"	—	50	90043A055	00000
								5/8"-11	1"	35/64"	—	25	90043A065	00000
								3/4"-10	1 1/8"	21/32"	—	10	90043A075	00000
7/8"-9								1 5/16"	49/64"	—	5	90043A085	00000
1"-8	1 1/2"							7/8"	—	5	90043A095	00000
1 1/8"-7	1 11/16"							1"	—	1	90043A105	0000
1 1/4"-7	1 7/8"							1 3/32"	—	1	90043A115	0000
1 1/2"-6	2 1/4"							1 5/16"	—	1	90043A125	0000


Steel—ISO Class 5



								M4 × 0.7 mm	7 mm	3 mm	DIN 557	50	96887A111	0000
								M5 × 0.8 mm	8 mm	4 mm	DIN 557	50	96887A112	00000
								M6 × 1 mm	10 mm	5 mm	DIN 557	25	96887A113	0000
								M8 × 1.25 mm	13 mm	6.5 mm	DIN 557	25	96887A114	0000
								M10 × 1.5 mm	17 mm	8 mm	DIN 557	10	96887A115	0000
								M12 × 1.75 mm	19 mm	10 mm	DIN 557	5	96887A116	0000


								Zinc-Plated Steel—ISO Class 5



										M4 × 0.7 mm	7 mm	3.2 mm	DIN 557	100	96887A329	00000
		M5 × 0.8 mm								8 mm	4 mm	DIN 557	100	96887A331	00000
		M6 × 1 mm	10 mm							5 mm	DIN 557	100	96887A319	00000
		M8 × 1.25 mm	13 mm							6.5 mm	DIN 557	25	96887A322	0000
		M10 × 1.5 mm	17 mm							8 mm	DIN 557	25	96887A325	00000
		M12 × 1.75 mm	19 mm							10 mm	DIN 557	10	96887A328	0000
		M16 × 2 mm	24 mm							13 mm	DIN 557	5	96887A332	00000
		M20 × 2.5 mm	30 mm							16 mm	DIN 557	5	96887A334	00000


		Black-Zinc-Plated Steel—ISO Class 5



				M4 × 0.7 mm	7 mm					3 mm	DIN 557	25	96887A118	0000
				M5 × 0.8 mm	8 mm					4 mm	DIN 557	25	96887A119	0000
				M6 × 1 mm	10 mm					5 mm	DIN 557	25	96887A121	0000
				M8 × 1.25 mm	13 mm					6.5 mm	DIN 557	10	96887A122	0000
				M10 × 1.5 mm	17 mm					8 mm	DIN 557	10	96887A123	00000
				M16 × 2 mm	24 mm					13 mm	DIN 557	1	96887A125	0000

18-8 Stainless Steel Square Nuts

These square nuts have good chemical resistance and may be mildly magnetic. Large flat sides make them easy to grip with a wrench and keep them from rotating in channels and square holes.

	Wd.	Ht.	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	2-56	3/16"	1/16"	—	100	94785A509	000000
	4-40	1/4"	3/32"	—	100	94785A511	00000
	6-32	5/16"	7/64"	—	100	94785A007	00000
	8-32	11/32"	1/8"	—	100	94785A009	00000
	10-24	3/8"	1/8"	—	100	94785A013	00000
	10-32	3/8"	1/8"	—	100	94785A411	00000
	1/4"-20	7/16"	3/16"	—	50	94785A415	00000
	1/4"-28	7/16"	3/16"	—	25	94785A439	0000
	5/16"-18	9/16"	7/32"	—	25	94785A419	0000
	5/16"-24	9/16"	7/32"	—	10	94785A441	0000


	3/8"-16	5/8"	1/4"	—	25	94785A423	00000
	3/8"-24	5/8"	1/4"	—	10	94785A442	0000
	7/16"-14	3/4"	3/8"	—	5	94785A443	0000
	7/16"-20	3/4"	3/8"	—	5	94785A445	00000
	1/2"-13	13/16"	7/16"	—	5	94785A427	0000
	5/8"-11	1"	35/64"	—	1	94785A431	0000
	3/4"-10	1 1/8"	21/32"	—	1	94785A435	0000
	1"-8	1 1/2"	7/8"	—	1	94785A438	00000
	M5 × 0.8 mm	8 mm	4 mm	DIN 557	50	90225A101	0000
	M6 × 1 mm	10 mm	5 mm	DIN 557	50	90225A102	00000


	M8 × 1.25 mm	13 mm	6.5 mm	DIN 557	25	90225A103	00000
	M10 × 1.5 mm	17 mm	8 mm	DIN 557	10	90225A104	0000
	M12 × 1.75 mm	19 mm	10 mm	DIN 557	5	90225A105	00000
	M16 × 2 mm	24 mm	13 mm	DIN 557	1	90225A106	00000

18-8 Stainless Steel Thin-Profile Square Nuts

Two-thirds the height of typical square nuts and made of 18-8 stainless steel, these metric nuts are designed for use in low-clearance applications in humid, damp, and washdown environments. They’re often called square jam nuts because they can be jammed together to hold each other in place. They’re easily gripped with a wrench due to their flat, broad sides, which also prevent them from rotating in channels and square holes. Compared to hex nuts, a greater area is in contact with the fastened surface. And compared to steel nuts, they’re slightly less strong.

Black-Oxide 18-8 Stainless Steel—Black-oxide 18-8 stainless steel nuts have a dark surface color.

DIN 562—These nuts meet DIN 562, an international standard that signifies their material and dimensions are compatible with other products and tools.

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



	M2 × 0.4 mm	4	1.2	DIN 562	25	97258A121	000000
	M2.5 × 0.45 mm	5	1.6	DIN 562	25	97258A122	00000
	M3 × 0.5 mm	5.5	1.8	DIN 562	50	97258A101	0000
	M4 × 0.7 mm	7	2.2	DIN 562	50	97258A102	00000
	M5 × 0.8 mm	8	2.7	DIN 562	50	97258A103	0000
	M6 × 1 mm	10	3.2	DIN 562	50	97258A104	00000
	M8 × 1.25 mm	13	4	DIN 562	25	97258A105	00000
	M10 × 1.5 mm	17	5	DIN 562	10	97258A106	0000


	Black-Oxide 18-8 Stainless Steel



			M3 × 0.5 mm	5.5	1.8	DIN 562	10	97258A123	00000
			M4 × 0.7 mm	7	2.2	DIN 562	10	97258A124	00000

Medium-Strength Steel Thin-Profile Square Nuts

Made of ISO Class 04 steel and about two-thirds the height of standard steel square nuts, these nuts are suitable for most low-clearance fastening applications. Also known as square jam nuts, they’re commonly jammed together to hold each other in place. Their flat, broad sides make them easy to grip with a wrench and keep them from rotating in channels and square holes. Compared to hex nuts, a greater area is in contact with the fastened surface.

Black-Oxide Steel—Black-oxide steel square nuts have a dark surface color and are mildly corrosion resistant in dry environments.

Zinc-Plated Steel—Zinc-plated steel square nuts resist corrosion in wet environments.

DIN 562—These nuts meet DIN 562, an international standard that signifies their material and dimensions are compatible with other products and tools.

	Wd., mm	Ht., mm	Specs. Met	Pkg. Qty.		Pkg.
Black-Oxide Steel—ISO Class 04



	M3 × 0.5 mm	5.5	1.8	DIN 562	10	97259A111	00000
	M4 × 0.7 mm	7	2.2	DIN 562	10	97259A112	0000


	Zinc-Plated Steel—ISO Class 04



			M3 × 0.5 mm	5.5	1.8	DIN 562	100	97259A101	0000
			M4 × 0.7 mm	7	2.2	DIN 562	100	97259A102	0000
			M5 × 0.8 mm	8	2.7	DIN 562	100	97259A103	00000
			M6 × 1 mm	10	3.2	DIN 562	100	97259A104	00000
			M8 × 1.25 mm	13	4	DIN 562	50	97259A105	00000
			M10 × 1.5 mm	17	5	DIN 562	25	97259A106	00000

Super-Corrosion-Resistant 316 Stainless Steel Square Nuts

These square nuts have excellent resistance to chemicals and salt water. Large flat sides make them easy to grip with a wrench and keep them from rotating in channels and square holes.

	Wd.	Ht.	Pkg. Qty.		Pkg.
316 Stainless Steel



	4-40	1/4"	3/32"	100	92891A101	000000
	6-32	5/16"	7/64"	100	92891A500	00000
	8-32	11/32"	1/8"	50	92891A600	00000
	10-24	3/8"	1/8"	50	92891A700	00000
	10-32	3/8"	1/8"	50	92891A800	00000
	1/4"-20	7/16"	3/16"	25	92891A100	00000
	1/4"-28	7/16"	3/16"	25	92891A104	0000
	5/16"-18	9/16"	7/32"	10	92891A200	0000
	3/8"-16	5/8"	1/4"	10	92891A300	00000
	1/2"-13	13/16"	7/16"	1	92891A400	0000


	5/8"-11	1"	35/64"	1	92891A102	0000
	3/4"-10	1 1/8"	21/32"	1	92891A103	00000

Brass Square Nuts

These square nuts are corrosion resistant in wet environments, electrically conductive, and nonmagnetic. Large flat sides make them easy to grip with a wrench and keep them from rotating in channels and square holes.

	Wd.	Ht.	Pkg. Qty.		Pkg.
Brass



	4-40	1/4"	3/32"	100	90509A029	00000
	6-32	5/16"	7/64"	100	90509A030	00000
	8-32	11/32"	1/8"	50	90509A031	0000
	10-24	3/8"	1/8"	50	90509A032	00000
	10-32	3/8"	1/8"	50	90509A033	00000
	1/4"-20	7/16"	3/16"	25	90509A034	00000
	5/16"-18	9/16"	7/32"	10	90509A035	0000
	3/8"-16	5/8"	1/4"	10	90509A036	00000
	1/2"-13	13/16"	7/16"	5	90509A037	00000

Medium-Strength Steel Square Nuts

Large flat sides make these nuts easy to grip with a wrench and keep them from rotating in channels and square holes. Made from SAE Grade 5 steel, they're suitable for fastening most machinery and equipment.

Steel—Steel square nuts are best for dry environments, since moisture will cause them to rust.

Zinc-Plated Steel—Zinc-plated steel square nuts resist corrosion in wet environments.

	Wd.	Ht.	Pkg. Qty.		Pkg.
Steel—SAE Grade 5



	1/4"-20	7/16"	7/32"	100	98694A211	00000
	5/16"-18	9/16"	17/64"	50	98694A212	0000
	3/8"-16	5/8"	21/64"	25	98694A213	0000
	7/16"-14	3/4"	3/8"	10	98694A214	0000
	1/2"-13	13/16"	7/16"	10	98694A215	0000
	5/8"-11	1"	35/64"	5	98694A216	0000
	3/4"-10	1 1/8"	21/32"	5	98694A217	0000
	7/8"-9	1 5/16"	49/64"	1	98694A218	0000
	1"-8	1 1/2"	7/8"	1	98694A219	0000
	1 1/4"-7	1 7/8"	1 3/32"	1	98694A221	0000


	Zinc-Plated Steel—SAE Grade 5



			1/4"-20	7/16"	7/32"	100	98694A110	0000
			5/16"-18	9/16"	17/64"	100	98694A115	00000
			3/8"-16	5/8"	21/64"	50	98694A120	00000
			7/16"-14	3/4"	3/8"	25	98694A125	00000
			1/2"-13	13/16"	7/16"	25	98694A130	00000
			5/8"-11	1"	35/64"	10	98694A135	0000
			3/4"-10	1 1/8"	21/32"	10	98694A140	00000
			7/8"-9	1 5/16"	49/64"	5	98694A145	00000
			1"-8	1 1/2"	7/8"	1	98694A150	0000
			1 1/8"-7	1 11/16"	1"	1	98694A155	0000


			1 1/4"-7	1 7/8"	1 3/32"	1	98694A160	0000
			1 1/2"-6	2 1/4"	1 5/16"	1	98694A165	00000

Fiberglass Square Nuts

These fiberglass square nuts are chemical resistant, nonconductive, and lightweight. Large flat sides make them easy to grip with a wrench and keep them from rotating in channels and square holes.

	Wd.	Ht.	Max. Temp.	Color	Pkg. Qty.		Pkg.
Fiberglass



	3/8"-16	3/4"	17/32"	Not Rated	Gray	1	91332A031	00000
	1/2"-13	7/8"	41/64"	Not Rated	Gray	1	91332A033	0000
	5/8"-11	1 1/8"	51/64"	Not Rated	Gray	1	91332A035	0000
	3/4"-10	1 1/4"	57/64"	Not Rated	Gray	1	91332A036	0000
	1"-8	1 11/16"	1 9/64"	Not Rated	Gray	1	91332A038	00000

Ultra-High-Temperature Carbon Fiber Square Nuts

Unlike metal nuts, these carbon fiber square nuts won’t warp at extreme temperatures, making them ideal for heat treating and furnace fixtures. They are lightweight with an excellent strength-to-weight ratio and can be used for storage racks and shelving. Large flat sides make these nuts easy to grip with a wrench and keep them from rotating in channels and square holes. Not for use in oxidizing environments.

	Wd.	Ht.	Tensile Strength, psi	Max. Temp., ° F		Each
Carbon Fiber



	1/4"-20	1/2"	1/4"	17,000	3,990	91971A011	00000
	5/16"-18	5/8"	1/4"	17,000	3,990	91971A012	0000
	3/8"-16	3/4"	13/32"	17,000	3,990	91971A013	00000
	1/2"-13	1"	1/2"	17,000	3,990	91971A014	00000
	M6 × 1 mm	1/2"	1/4"	17,000	3,990	90713A011	0000
	M8 × 1.25 mm	1/2"	1/4"	17,000	3,990	90713A012	00000