ISO Class 8.8 Washers | McMaster-Carr

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General Purpose Washers

Your go-to metal washer for every screw size. Washers take the pressure off nuts and screws to protect mounting surfaces.

Steel

Zinc-Plated Steel—A common choice for areas with occasional exposure to moisture.

Zinc-Yellow-Chromate-Plated Steel—With the same corrosion resistance as zinc-plated steel, these withstand occasional exposure to moisture.

Highly Corrosion-Resistant Zinc-Flake-Coated Steel—With 40 times the corrosion resistance of zinc-plated steel, the coating has been tested to extreme standards, including 1,000 hours of salt spray, to hold up in wet and outdoor environments. They are similar to Magni-coated washers.

Large Pack—Priced at least 30% lower per washer than small packs.

For Fastener Strength Grade/Class—If you require screws or nuts with a specific fastener strength rating, make sure your washer matches the grade or class.

						Imported—Small Pack			Imported—Large Pack			United States Origin—Small Pack
	For Screw Size	ID, mm	OD, mm	Thk., mm	For Fastener Strength Grade/Class	Pkg. Qty.		Pkg.	Pkg. Qty.		Pkg.	Pkg. Qty.		Pkg.
Zinc-Plated Steel



		M2	2.2	5.0	0.2 to 0.4	Class 8.8	100	91455A310	00000	—	———	0	—	———	0


		M2.5	2.7	6.0	0.4 to 0.6	Class 8.8	100	91455A320	0000	—	———	0	—	———	0
		M3	3.2	7.0	0.4 to 0.6	Class 8.8	100	91455A330	0000	—	———	0	—	———	0
		M4	4.3	9.0	0.7 to 0.9	Class 8.8	100	91455A340	0000	—	———	0	—	———	0
		M5	5.3	10.0	0.9 to 1.1	Class 8.8	100	91455A110	0000	—	———	0	—	———	0
		M6	6.4	12.0	1.4 to 1.8	Class 8.8	100	91455A120	0000	—	———	0	—	———	0
		M8	8.4	16.0	1.4 to 1.8	Class 8.8	100	91455A130	0000	—	———	0	—	———	0
		M10	10.5	20.0	1.8 to 2.2	Class 8.8	100	91455A140	0000	—	———	0	—	———	0
		M12	13.0	24.0	2.3 to 2.7	Class 8.8	50	91455A150	0000	—	———	0	—	———	0
		M14	15.0	28.0	2.3 to 2.7	Class 8.8	50	91455A160	00000	—	———	0	—	———	0
		M16	17.0	30.0	2.7 to 3.3	Class 8.8	50	91455A170	00000	—	———	0	—	———	0


		M18	19.0	34.0	2.7 to 3.3	Class 8.8	25	91455A175	00000	—	———	0	—	———	0
		M20	21.0	37.0	2.7 to 3.3	Class 8.8	25	91455A180	00000	—	———	0	—	———	0
		M22	23.0	39.0	2.7 to 3.3	Class 8.8	—	———	0	—	———	0	5	98688A182	000000
		M24	25.0	44.0	3.7 to 4.3	Class 8.8	5	91455A190	0000	—	———	0	—	———	0
		M30	31.0	56.0	3.7 to 4.3	Class 8.8	5	91455A220	0000	—	———	0	—	———	0
		M36	37.0	66.0	4.4 to 5.6	Class 8.8	1	91455A350	0000	—	———	0	—	———	0
		M39	40.0	72.0	5.4 to 6.6	Class 8.8	1	91455A360	0000	—	———	0	—	———	0
		M42	43.0	78.0	6.0 to 8.0	Class 8.8	1	91455A370	00000	—	———	0	—	———	0


		Zinc-Yellow-Chromate-Plated Steel



				M6	6.5	12.0	1.5 to 1.6	Class 8.8	250	90483A101	0000	5,000	90483A111	000000	—	———	0


				M8	8.5	16.0	1.4 to 1.5	Class 8.8	250	90483A102	00000	2,000	90483A121	00000	—	———	0
				M10	10.6	20.0	1.9 to 2.0	Class 8.8	100	90483A103	0000	2,000	90483A131	000000	—	———	0
				M12	13.1	24.0	2.4 to 2.5	Class 8.8	50	90483A104	0000	1,000	90483A141	00000	—	———	0
				M14	15.0	28.0	2.3 to 2.7	Class 8.8	25	90483A211	0000	—	———	0	—	———	0
				M16	17.1	30.0	2.9 to 3.0	Class 8.8	25	90483A105	0000	500	90483A161	00000	—	———	0
				M20	21.1	37.0	2.9 to 3.0	Class 8.8	25	90483A106	0000	—	———	0	—	———	0
				M22	23.0	39.0	2.7 to 3.3	Class 8.8	25	90483A108	0000	—	———	0	—	———	0
				M24	25.2	44.0	3.9	Class 8.8	10	90483A107	0000	—	———	0	—	———	0
				M30	31.0	56.0	3.7 to 4.3	Class 8.8	10	90483A109	0000	—	———	0	—	———	0


				Highly Corrosion-Resistant Zinc-Flake-Coated Steel



						M4	4.3	9.0	0.7 to 0.9	Class 8.8	50	91455A410	00000	—	———	0	—	———	0


						M5	5.3	10.0	0.9 to 1.1	Class 8.8	50	91455A420	00000	—	———	0	—	———	0
						M6	6.4	12.0	1.4 to 1.8	Class 8.8	50	91455A430	00000	—	———	0	—	———	0
						M8	8.4	16.0	1.4 to 1.8	Class 8.8	50	91455A440	00000	—	———	0	—	———	0
						M10	10.5	20.0	1.8 to 2.2	Class 8.8	25	91455A450	00000	—	———	0	—	———	0
						M12	13.0	24.0	2.3 to 2.7	Class 8.8	10	91455A460	0000	—	———	0	—	———	0
						M14	15.0	28.0	2.3 to 2.7	Class 8.8	10	91455A470	00000	—	———	0	—	———	0
						M16	17.0	30.0	2.7 to 3.3	Class 8.8	10	91455A480	00000	—	———	0	—	———	0
						M18	19.0	34.0	2.7 to 3.3	Class 8.8	5	91455A490	00000	—	———	0	—	———	0
						M20	21.0	37.0	2.7 to 3.3	Class 8.8	5	91455A510	00000	—	———	0	—	———	0
						M24	25.0	44.0	3.7 to 4.3	Class 8.8	1	91455A520	0000	—	———	0	—	———	0


M30	31.0					56.0	3.7 to 4.3	Class 8.8	1	91455A530	00000	—	———	0	—	———	0

Oversized Washers

Cover oversized holes or use these washers as spacers and levelers. Compared to general purpose washers, these have a larger diameter or thickness.

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

Steel

Image of Product. Front orientation. Contains Annotated. Washers. Oversized Washers.

Image of Specification. Front orientation. Washers. Oversized Washers.

Zinc-Plated Steel—A common choice for areas with occasional exposure to moisture.

Material Certificate—Washers include a report with a traceable lot number.

For Fastener Strength Grade/Class—If you require screws or nuts with a specific fastener strength rating, make sure your washer matches the grade or class.

	ID, mm	OD, mm	Thk., mm	For Fastener Strength Grade/Class	Certificate Type	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M3	3.3	8.7	0.7 to 0.9	Class 8.8	Material Certificate	100	91100A341	000000


	M3	3.3	8.7	0.9 to 1.1	Class 8.8	Material Certificate	100	91100A342	00000
	M4	4.4	11.7	0.9 to 1.1	Class 8.8	Material Certificate	100	91100A343	00000
	M4	4.4	11.7	1.4 to 1.8	Class 8.8	Material Certificate	50	91100A344	00000
	M5	5.4	14.7	1.0 to 1.4	Class 8.8	Material Certificate	100	91100A345	00000
	M5	5.4	14.7	1.8 to 2.2	Class 8.8	Material Certificate	50	91100A346	00000
	M6	6.5	16.7	2.7 to 3.3	Class 8.8	Material Certificate	25	91100A348	00000
	M6	6.5	17.7	1.4 to 1.8	Class 8.8	Material Certificate	50	91100A347	00000
	M8	8.5	20.7	3.7 to 4.3	Class 8.8	Material Certificate	10	91100A351	00000
	M8	8.5	23.7	1.8 to 2.2	Class 8.8	Material Certificate	25	91100A349	00000
	M10	10.6	24.7	3.7 to 4.3	Class 8.8	Material Certificate	10	91100A353	00000


	M10	10.6	29.7	2.3 to 2.7	Class 8.8	Material Certificate	10	91100A352	00000
	M12	13.1	36.6	2.7 to 3.3	Class 8.8	Material Certificate	5	91100A354	00000
	M16	17.1	49.6	2.7 to 3.3	Class 8.8	Material Certificate	1	91100A356	0000
	M20	22.2	58.4	3.4 to 4.6	Class 8.8	Material Certificate	1	91100A358	0000

Tension-Indicating Structural Washers

Fasten structural screws and nuts securely without overtightening. When you see orange dye, you'll know you've applied the correct tension, so you don't accidentally strip threads. These washers distribute pressure under fasteners in columns, joists, and I-beams. They are tested and certified to meet industry standards for handling high-stress loads.

Steel

Corrosion-Resistant Galvanized Steel—These washers combine the strength of steel with the rust resistance of stainless steel. They're an economical alternative to 18-8 stainless steel in wet and outdoor environments, but they won't hold up to salt water and chemicals.

For Fastener Strength Grade/Class—If you require screws or nuts with a specific fastener strength rating, make sure your washer matches the grade or class.

	ID, mm	OD, mm	Thk., mm	For Fastener Strength Grade/Class	Specs. Met	Pkg. Qty.		Pkg.
Corrosion-Resistant Galvanized Steel



	M12	12.6	27.3	2.6 to 4.6	Class 8.8	ASME B18.2.6M, ASTM F959	10	95318A120	000000


	M16	16.7	33.6	3.2 to 5.5	Class 8.8	ASME B18.2.6M, ASTM F959	5	95318A121	0000
	M20	21.0	40.6	3.6 to 6.0	Class 8.8	ASME B18.2.6M, ASTM F959	5	95318A122	00000
	M22	23.0	42.9	3.6 to 6.0	Class 8.8	ASME B18.2.6M, ASTM F959	5	95318A123	00000
	M24	25.1	48.7	4.0 to 7.0	Class 8.8	ASME B18.2.6M, ASTM F959	1	95318A124	0000
	M27	28.4	54.4	4.0 to 7.0	Class 8.8	ASME B18.2.6M, ASTM F959	1	95318A125	0000
	M30	31.4	58.4	4.0 to 7.0	Class 8.8	ASME B18.2.6M, ASTM F959	1	95318A126	00000
	M36	37.7	70.4	4.8 to 7.5	Class 8.8	ASME B18.2.6M, ASTM F959	1	95318A127	0000

Undersized Washers

These washers distribute pressure evenly under fasteners with narrow heads, such as cheese and socket head screws. They have smaller diameters than general purpose washers of the same screw size.

Steel

Zinc-Plated Steel—A common choice for areas with occasional exposure to moisture.

Material Certificate—Washers include a report with a traceable lot number.

For Fastener Strength Grade/Class—If you require screws or nuts with a specific fastener strength rating, make sure your washer matches the grade or class.

	ID, mm	OD, mm	Thk., mm	For Fastener Strength Grade/Class	Certificate Type	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M3	3.2	6.0	0.4 to 0.6	Class 8.8	Material Certificate	100	98688A174	00000


	M4	4.3	8.0	0.4 to 0.6	Class 8.8	Material Certificate	100	98688A175	0000
	M5	5.3	9.0	0.9 to 1.1	Class 8.8	Material Certificate	100	98688A176	0000
	M6	6.4	11.0	1.4 to 1.8	Class 8.8	Material Certificate	100	98688A171	00000
	M8	8.4	15.0	1.4 to 1.8	Class 8.8	Material Certificate	50	98688A172	00000
	M10	10.5	18.0	1.4 to 1.8	Class 8.8	Material Certificate	50	98688A173	00000
	M12	13.0	20.0	1.8 to 2.2	Class 8.8	Material Certificate	25	98688A177	00000
	M14	15.0	24.0	2.3 to 2.7	Class 8.8	Material Certificate	10	98688A178	0000
	M16	17.0	28.0	2.3 to 2.7	Class 8.8	—	10	98688A179	00000
	M20	21.0	34.0	2.7 to 3.3	Class 8.8	—	5	98688A181	00000
	M24	25.0	39.0	3.7 to 4.3	Class 8.8	—	1	98688A183	0000

Steel Hex Head Screw Kits


	Fully Threaded	Partially Threaded	Class 8.8

Everything you need for a complete, strong joint—the screws in these kits come with compatible nuts and washers. The screws have a head with six flat sides to keep wrenches and sockets from slipping and rounding off the drive. Washers distribute pressure on both sides of your material, so the nut tightens onto the screw without damaging surfaces.

Screw length is measured from under the head.

Medium-Strength Fastener—Your go-to screws for fastening most machinery and equipment. They have tensile strengths from 90,000 to 120,000 psi.

Zinc-Plated Steel—A common choice for areas with occasional exposure to moisture.

	Screw							Nut			Washer
	Lg., mm	Head Wd., mm	Head Ht., mm	Threading	Thread Spacing	Fastener Strength Grade/Class	Tensile Strength, psi	Wd., mm	Ht., mm	Fastener Strength Grade/Class	ID, mm	OD, mm	Thk., mm	Fastener Strength Grade/Class	Includes		Each
Medium-Strength Zinc-Plated Steel







				M6 × 1 mm

				12	10	4	Fully Threaded	Coarse	Class 8.8	116,000	10	5.2	Class 8	6.6	12	1.8	Class 8.8	50 Hex Head Screws 50 Hex Nuts 100 Flat Washers	97379A111	000000


				16	10	4	Fully Threaded	Coarse	Class 8.8	116,000	10	5.2	Class 8	6.6	12	1.8	Class 8.8	50 Hex Head Screws 50 Hex Nuts 100 Flat Washers	97379A112	00000
				20	10	4	Partially Threaded	Coarse	Class 8.8	116,000	10	5.2	Class 8	6.6	12	1.8	Class 8.8	50 Hex Head Screws 50 Hex Nuts 100 Flat Washers	97379A113	00000
				25	10	4	Partially Threaded	Coarse	Class 8.8	116,000	10	5.2	Class 8	6.6	12	1.8	Class 8.8	50 Hex Head Screws 50 Hex Nuts 100 Flat Washers	97379A114	00000
				30	10	4	Partially Threaded	Coarse	Class 8.8	116,000	10	5.2	Class 8	6.6	12	1.8	Class 8.8	50 Hex Head Screws 50 Hex Nuts 100 Flat Washers	97379A115	00000




						M8 × 1.25 mm

						25	13	5.3	Partially Threaded	Coarse	Class 8.8	116,000	13	6.5	Class 8	8.6	16	1.8	Class 8.8	25 Hex Head Screws 25 Hex Nuts 50 Flat Washers	97379A116	00000


						30	13	5.3	Partially Threaded	Coarse	Class 8.8	116,000	13	6.5	Class 8	8.6	16	1.8	Class 8.8	25 Hex Head Screws 25 Hex Nuts 50 Flat Washers	97379A117	00000
						35	13	5.3	Partially Threaded	Coarse	Class 8.8	116,000	13	6.5	Class 8	8.6	16	1.8	Class 8.8	25 Hex Head Screws 25 Hex Nuts 50 Flat Washers	97379A118	00000
						40	13	5.3	Partially Threaded	Coarse	Class 8.8	116,000	13	6.5	Class 8	8.6	16	1.8	Class 8.8	25 Hex Head Screws 25 Hex Nuts 50 Flat Washers	97379A119	00000




								M10 × 1.5 mm

								25	17	6.4	Fully Threaded	Coarse	Class 8.8	116,000	17	8	Class 8	10.8	20	2.2	Class 8.8	25 Hex Head Screws 25 Hex Nuts 50 Flat Washers	97379A121	00000


								30	17	6.4	Partially Threaded	Coarse	Class 8.8	116,000	17	8	Class 8	10.8	20	2.2	Class 8.8	25 Hex Head Screws 25 Hex Nuts 50 Flat Washers	97379A122	00000
								35	17	6.4	Partially Threaded	Coarse	Class 8.8	116,000	17	8	Class 8	10.8	20	2.2	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A123	0000
								40	17	6.4	Partially Threaded	Coarse	Class 8.8	116,000	17	8	Class 8	10.8	20	2.2	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A124	0000
								50	17	6.4	Partially Threaded	Coarse	Class 8.8	116,000	17	8	Class 8	10.8	20	2.2	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A125	0000
								60	17	6.4	Partially Threaded	Coarse	Class 8.8	116,000	17	8	Class 8	10.8	20	2.2	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A126	00000




										M12 × 1.75 mm

										25	19	7.5	Fully Threaded	Coarse	Class 8.8	116,000	19	10	Class 8	13.3	24	2.7	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A128	0000


										30	19	7.5	Fully Threaded	Coarse	Class 8.8	116,000	19	10	Class 8	13.3	24	2.7	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A129	0000
										35	19	7.5	Partially Threaded	Coarse	Class 8.8	116,000	19	10	Class 8	13.3	24	2.7	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A131	00000
										40	19	7.5	Partially Threaded	Coarse	Class 8.8	116,000	19	10	Class 8	13.3	24	2.7	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A132	00000
										50	19	7.5	Partially Threaded	Coarse	Class 8.8	116,000	19	10	Class 8	13.3	24	2.7	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A133	00000
										60	19	7.5	Partially Threaded	Coarse	Class 8.8	116,000	19	10	Class 8	13.3	24	2.7	Class 8.8	10 Hex Head Screws 10 Hex Nuts 20 Flat Washers	97379A134	00000
										100	19	7.5	Partially Threaded	Coarse	Class 8.8	116,000	19	10	Class 8	13.3	24	2.7	Class 8.8	5 Hex Head Screws 5 Hex Nuts 10 Flat Washers	97379A127	00000

Steel Hex Head Screw, Nut, and Washer Assortments


	Class 8.8

Keep a range of hex head screw, nut, and washer sizes on hand for a variety of jobs. The screws in these assortments have heads with six flat sides to keep wrenches and sockets slipping and rounding off the drive.

Length is measured from under the head.

Medium-Strength Fastener—Your go-to screws for fastening most machinery and equipment. They have tensile strengths from 90,000 to 120,000 psi.

Zinc-Plated Steel—A common choice for areas with occasional exposure to moisture.

Steel—Unfinished steel screws are best for dry environments, since moisture will cause them to rust. They require little surface prep before applying a finish, so you can apply your own paint or coating.

	Hex Head Screws Included	Hex Nuts Included	Split Lock Washers Included	Flat Washers Included	Fastener Strength Grade/Class	Container Type		Each
Medium-Strength Zinc-Plated Steel



	305	M10 × 1.5 mm Thread: 16 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, and 60 mm Lg. (135 pieces)	M10 × 1.5 mm Thread (45 Pieces)	For M10 Screw Size (60 Pieces)	For M10 Screw Size (65 pieces)	Class 8.8, Class 8	Metal Box	94147A113	000000


	600	M8 × 1.25 mm Thread: 12 mm, 16 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 50 mm, and 60 mm Lg. (185 pieces)	M8 × 1.25 mm Thread (135 Pieces)	For M8 Screw Size (90 Pieces)	For M8 Screw Size (190 pieces)	Class 8.8, Class 8	Metal Box	94147A112	00000
	670	M6 × 1 mm Thread: 12 mm, 16 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 50 mm, and 60 mm Lg. (325 pieces)	M6 × 1 mm Thread (75 Pieces)	For M6 Screw Size (120 Pieces)	For M6 Screw Size (150 pieces)	Class 8.8, Class 8	Metal Box	94147A111	00000
	2,295	M4 × 0.7 mm Thread: 10 mm, 16 mm, 20 mm, 25 mm, 30 mm, and 35 mm Lg. (300 Pieces) M5 × 0.8 mm Thread: 16 mm, 20 mm, 25 mm, 30 mm, 35 mm, and 40 mm Lg. (300 Pieces) M6 × 1 mm Thread: 16 mm, 25 mm, and 30 mm Lg. (75 pieces) M8 × 1.25 mm Thread: 16 mm, 25 mm, and 35 mm Lg. (45 pieces) M10 × 1.5 mm Thread: 16 mm, 25 mm, and 35 mm Lg. (30 pieces) M12 × 1.75 mm Thread: 20 mm, 30 mm, and 60 mm Lg. (15 pieces)	M4 × 0.7 mm Thread (300 Pieces) M5 × 0.8 mm Thread (300 Pieces) M6 × 1 mm Thread (75 Pieces) M8 × 1.25 mm Thread (45 Pieces) M10 × 1.5 mm Thread (30 Pieces) M12 × 1.75 mm Thread (15 Pieces)	For M4 Screw Size (300 Pieces) For M5 Screw Size (300 Pieces) For M6 Screw Size (75 Pieces) For M8 Screw Size (45 Pieces) For M10 Screw Size (30 Pieces) For M12 Screw Size (15 Pieces)	—	Class 8.8, Class 8	Metal Box Plastic Box	98620A100	000000


	Medium-Strength Steel



			2,295	M4 × 0.7 mm Thread: 10 mm, 16 mm, 20 mm, 25 mm, 30 mm, and 35 mm Lg. (300 Pieces) M5 × 0.8 mm Thread: 16 mm, 20 mm, 25 mm, 30 mm, 35 mm, and 40 mm Lg. (300 Pieces) M6 × 1 mm Thread: 16 mm, 25 mm, and 35 mm Lg. (75 Pieces) M8 × 1.25 mm Thread: 16 mm, 25 mm, and 35 mm Lg. (45 pieces) M10 × 1.5 mm Thread: 16 mm, 25 mm, and 35 mm Lg. (30 pieces) M12 × 1.75 mm Thread: 20 mm, 30 mm, and 60 mm Lg. (15 pieces)	M4 × 0.7 mm Thread (300 Pieces) M5 × 0.8 mm Thread (300 Pieces) M6 × 1 mm Thread (75 Pieces) M8 × 1.25 mm Thread (45 Pieces) M10 × 1.5 mm Thread (30 Pieces) M12 × 1.75 mm Thread (15 Pieces)	For M4 Screw Size (300 Pieces) For M5 Screw Size (300 Pieces) For M6 Screw Size (75 Pieces) For M8 Screw Size (45 Pieces) For M10 Screw Size (30 Pieces) For M12 Screw Size (15 Pieces)	—	Class 8.8, Class 8	Metal Box Plastic Box	98620A080	000000