M3.5 Washers | McMaster-Carr

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45 Products

General Purpose Washers

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

Stainless Steel About Stainless Steel

18-8 Stainless Steel—The choice for wet and outdoor environments, these washers 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 washers have a dark, matte coating to create a finished look. They resist rust in wet and outdoor environments, but won't hold up to harsh chemicals as well as 316 stainless steel.

Highly-Corrosion-Resistant 316 Stainless Steel—Superior to 18-8 stainless steel, these washers won't degrade when exposed to harsh weather, salt water, and most chemicals.

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M3.5	3.7	8.0	0.4 to 0.6	DIN 125, ISO 7089	100	000000000	00000


	Black-Oxide 18-8 Stainless Steel



			M3.5	3.7	8.0	0.5 to 0.6	DIN 125	100	000000000	00000


			Highly-Corrosion-Resistant 316 Stainless Steel



					M3.5	3.7	8.0	0.4 to 0.6	DIN 125, ISO 7089	100	000000000	0000

Steel

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

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M3.5	3.7	8.0	0.4 to 0.6	DIN 125, ISO 7089	100	000000000	00000

Aluminum

One-third the weight of steel, these washers are commonly used in robotics, automation, and other applications that have weight limits. They're an alternative to stainless steel for rust resistance, but aren't as strong.

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
Aluminum



	M3.5	3.7	8.0	0.4 to 0.6	DIN 125, ISO 7089	10	000000000	000000

Self-Retaining Washers

Save time by assembling screws and washers in advance. The tabs on these washers grip the screw shank, so they won't slip off, even when fastening upside down or at odd angles. They take the pressure off screws and nuts to protect mounting surfaces.

Nylon—The most popular plastic washers, these are strong, durable, and economical. Nylon will swell and weaken when exposed to moisture, so these washers are best for dry environments.

					Temp. Range, ° F
	For Screw Size	ID	OD	Thk.	Min.	Max.	Choose a Color	Pkg. Qty.		Pkg.
Nylon



		No. 6, M3.5	0.198"	0.328"	0.022" to 0.042"	-40	180	Black , Off-White	100	000000000	00000


		No. 6, M3.5	0.198"	0.328"	0.052" to 0.072"	-40	180	Black , Off-White	100	000000000	00000

Plastic Washers

All of these washers are lightweight, nonconductive, and naturally rust resistant. They are commonly used in electronics and automation applications to take the pressure off screws and nuts and protect mounting surfaces.

Nylon—The most popular plastic washers, these are strong, durable, and economical. Nylon will swell and weaken when exposed to moisture, so these washers are best for dry environments.

Moisture-Resistant Delrin® Acetal—The best plastic for damp and wet environments, these washers won't swell or lose their strength if exposed to moisture.

Clear Impact-Resistant Polycarbonate—Withstand bumps and vibration without cracking or denting. These washers are also clear to be less noticeable in your assembly.

Acid-Resistant PVC—A great choice for chemical-processing lines, these washers won't degrade when exposed to harsh acids, alkalis, and alcohols. They are also good electrical insulators.

Chemical-Resistant High-Temperature PTFE—The most chemical-resistant plastic washers we offer, these stand up to the widest range of harsh acids, bases, solvents, and corrosive cleaners, even at temperatures up to 500° F. Their slippery surface reduces friction between the washer, fastener, and mounting surface to prevent sticking when tightening and loosening. They are also good electrical insulators.

Extreme-Strength Electrically Insulating Phenolic— A close alternative to metal, these are the strongest of all our plastic washers and won't weaken, even when exposed to moisture. They protect components from unintentional electrical charges to prevent short circuits.

					Temp. Range, ° F
	For Screw Size	ID, mm	OD, mm	Thk., mm	Min.	Max.	Specs. Met	Color	Pkg. Qty.		Pkg.
Nylon



		M3.5	3.7	7.0	0.4 to 0.6	Not Rated	450	—	Off-White	25	000000000	000000


		M3.5	3.7	8.0	0.5 to 0.6	-40	212	DIN 125	Black	10	000000000	0000
		M3.5	3.7	8.0	0.6 to 1.0	Not Rated	220	—	Off-White	100	000000000	0000


		Moisture-Resistant Delrin® Acetal



				M3.5	3.7	8.0	0.4 to 0.6	Not Rated	180	—	White	10	000000000	00000


				Clear Impact-Resistant Polycarbonate



						M3.5	3.7	8.0	0.5 to 1.1	Not Rated	212	—	Clear	10	000000000	0000


						Acid-Resistant PVC



								M3.5	3.7	7.0	0.7 to 0.9	Not Rated	140	—	Gray	10	000000000	00000


								Chemical-Resistant High-Temperature PTFE



										M3.5	3.7	8.0	0.6 to 0.9	Not Rated	500	—	White	25	000000000	0000


										Extreme-Strength Electrically Insulating Phenolic



												M3.5	3.7	7.8	0.4 to 0.6	Not Rated	250	—	Brown	10	000000000	00000

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.

Stainless Steel About Stainless Steel

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

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M3.5	3.7	7.0	0.5 to 0.6	DIN 433	100	000000000	00000

Steel

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

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M3.5	3.7	7.0	0.4 to 0.6	DIN 433, ISO 7092	100	000000000	00000

Heavy-Vibration-Resistant Spring Lock Washers for Socket Head Screws

Stop socket head screws from wiggling loose on equipment with constant, vigorous vibration, such as engines, turbines, and generators. These washers have a small diameter to fit under screws with narrow heads. Similar to a spring, they flatten under pressure to add tension between mating surfaces. As long as the washers aren't deformed or otherwise damaged, you can reuse them indefinitely without losing locking strength. Also known as conical washers and Belleville washers.

Stack multiple washers in the same direction to double or triple how much weight they can bear. Stack washers in opposite directions for better deflection, which means they compress further and withstand more shock and movement without loosening.

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

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

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

Top-and-Bottom Serration—Adds friction for extra gripping power.

	ID	OD	Thk.	Overall Ht.	Serration Location	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	No. 6, M3.5	0.146"	0.236"	0.028"	0.045"	Top and Bottom	50	000000000	000000


	Zinc-Plated Steel



			No. 6, M3.5	0.146"	0.236"	0.020"	0.035"	Top and Bottom	100	000000000	00000


			Steel



					No. 6, M3.5	0.146"	0.236"	0.018"	0.035"	Top and Bottom	100	000000000	0000

Extreme-Vibration-Resistant Wedge Lock Washers

When it's critical to keep bolted assemblies secure, choose these two-piece lock washers with the tightest grip of all. They stop nuts and screws from loosening in heavy machinery that experiences jarring starts and stops, such as compressors and compactors. Serrations on the outside bite into the fastener and mating surfaces, while wedges on the inside lock the two pieces together. When the nut or screw starts to loosen, the wedges drive more tightly together to maintain tension. You can reuse these washers up to fifteen times, as long as the serrations and wedges are not worn down. They are comparable to NORD-LOCK® or Sherex TEC® washers.

Wedge Lock

Highly-Corrosion-Resistant 316 Stainless Steel—Superior to 18-8 stainless steel, these washers won't degrade when exposed to harsh weather, salt water, and most chemicals.

Highly-Corrosion-Resistant Zinc-Flake-Coated Steel—With 40 times the corrosion resistance of zinc-plated steel, these withstand rust as well as 316 stainless steel. They have been tested to extreme standards, including 1,000 hours of salt spray. They are similar to Magni-coated washers.

	ID	OD	Thk.	Pkg. Qty.		Pkg.
Highly-Corrosion-Resistant 316 Stainless Steel



	No. 6, M3.5	0.150"	0.300"	0.080" to 0.100"	1	000000000	00000


	No. 6, M3.5	0.150"	0.350"	0.080" to 0.100"	1	000000000	0000


	Highly-Corrosion-Resistant Zinc-Flake-Coated Steel



			No. 6, M3.5	0.150"	0.300"	0.060" to 0.080"	20	000000000	00000


			No. 6, M3.5	0.150"	0.350"	0.060" to 0.080"	20	000000000	00000

Tooth Lock Washers

Grip tighter than split lock washers to prevent nuts and screws from loosening in applications with constant movement, such as conveyors. Tooth lock washers typically can't be reused because the teeth often get bent when tightened.

External Tooth

Teeth on the outside edge bite into both the fastener and the mating surface for a stronger hold than internal-tooth lock washers. However, they may mar your material and snag on objects. Pair these washers with nuts and screws that are large enough to make contact with the teeth, such as pan, button, and binding head screws.

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

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M3.5	3.7	7.0	0.4 to 0.6	DIN 6797	100	000000000	00000


	Zinc-Plated Steel



			M3.5	3.9	7.0	0.9 to 1.2	DIN 6797	100	000000000	0000

Internal Tooth

Internal teeth dig into the nut or screw to prevent it from backing out. Unlike external-tooth lock washers, these have a smooth outside edge, so they are less likely to mar your material or snag on objects. However, they don’t grip quite as well. Pair them with fasteners that have small diameters, such as fillister and cheese head screws.

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

Black-Oxide Steel—Typically chosen for their appearance, these washers have a dark, matte coating that creates a finished look. They offer minimal corrosion resistance, so they're best for dry environments.

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M3.5	3.7	7.0	0.4 to 0.6	DIN 6797	100	000000000	00000


	Zinc-Plated Steel



			M3.5	3.7	7.0	0.4 to 0.6	DIN 6797	100	000000000	0000


			Black-Oxide Steel



					M3.5	3.7	7.0	0.4 to 0.6	DIN 6797	100	000000000	0000

Heavy-Vibration-Resistant Spring Lock Washers

With a grip that's second only to wedge lock, these washers stop nuts and screws from wiggling loose under constant, vigorous vibration. They are ideal for engines, turbines, generators, and other heavy duty equipment. Similar to a spring, they flatten under pressure to add tension between mating surfaces. As long as the washers aren't deformed or otherwise damaged, you can reuse them indefinitely without losing locking strength. Also known as conical washers and Belleville washers.

Acetal—Lightweight, nonconductive, and naturally rust resistant. These washers won't swell or lose their strength if exposed to moisture.

	ID	OD	Thk.	Overall Ht.	Pkg. Qty.		Pkg.
Acetal



	No. 6, M3.5	0.152"	0.316"	0.022" to 0.032"	0.045"	100	0000000	000000

Split Lock Washers

Stop nuts and screws from loosening due to mild vibration. As you tighten, the uneven ends bite into the nut or screw so it won't back out. While they're not as vibration resistant as other lock washers, they are a great fit for electrical panels, light fixtures, and other light duty assemblies. Split lock washers are not reusable, and they only work with fasteners that have right-hand threads.

Highly-Corrosion-Resistant 316 Stainless Steel—Superior to 18-8 stainless steel, these washers won't degrade when exposed to harsh weather, salt water, and most chemicals.

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

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

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M3.5	3.9	6.7	0.7 to 0.9	DIN 127B	100	000000000	00000


	Highly-Corrosion-Resistant 316 Stainless Steel



			M3.5	3.9	6.7	0.7 to 0.9	DIN 127B	100	000000000	0000


			Zinc-Plated Steel



					M3.5	3.6	6.7	0.7 to 0.9	DIN 127B	100	000000000	0000


					Steel



							M3.5	3.9	6.7	0.7 to 0.9	DIN 127B	100	000000000	0000

Clipped Washers

Clipped on one side, these washers fit in tight spots where your typical round washers can't. Position them against a flat edge, and they won't rotate out of place as you tighten. Washers take the pressure off screws and nuts to protect mounting surfaces.

Stainless Steel About Stainless Steel

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

	ID, mm	OD, mm	Clipped Wd., mm	Thk., mm	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M3.5	3.7	8.0	6.9	0.4 to 0.6	10	000000000	000000

Hard Fiber Washers

The least likely to scratch or mar delicate mounting surfaces, these washers are made of hardened cotton fiber. They are also naturally nonconductive, so they are a great choice for insulating nuts and screws to prevent unintended charges. However, fiber washers will break down faster than other washers and will need to be replaced more often.

For Screw Size	ID, mm	OD, mm	Thk., mm	Specs. Met	Color	Pkg. Qty.		Pkg.
M3.5	3.7	7.8	0.5 to 0.6	DIN 125	Black	10	000000000	000000

Stainless Steel Unthreaded Spacers

The most corrosion-resistant spacers we offer. Made of stainless steel, they won't rust or corrode when exposed to moisture and chemicals.

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

						Each
	Lg., mm	For Screw Size	ID, mm	Specs. Met		1-9	10-Up
18-8 Stainless Steel







				6 mm OD

				2	M3.5	3.700	ASTM A582	000000000	00000	00000


				4	M3.5	3.700	ASTM A582	000000000	0000	0000
				5	M3.5	3.700	ASTM A582	000000000	0000	0000
				6	M3.5	3.700	ASTM A582	000000000	0000	0000

Split Lock Washers for Socket Head Screws

Stop socket head screws from loosening due to mild vibration. These washers have a small diameter to fit under screws with narrow heads, but are still thick enough to keep fasteners secure. While they're not as vibration resistant as other lock washers, they are a great fit for electrical panels, light fixtures, and other light duty assemblies. Split lock washers are not reusable, and they only work with fasteners that have right-hand threads. Also known as high-collar lock washers.

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M3.5	3.9	6.1	0.9 to 1.1	DIN 7980	100	000000000	00000


	Black-Oxide Steel



			M3.5	3.9	6.1	0.9 to 1.1	DIN 7980	100	000000000	0000

Curved Spring Lock Washers

The curvy, spring-like shape adds a small amount of tension to prevent nuts and screws from backing out due to mild vibration. These washers also flex slightly to compensate for uneven surfaces. While more secure than a standard flat washer, these have the least amount of gripping power of all our lock washers. They are best suited for electrical panels, light fixtures, and other light duty assemblies. These washers hold their shape when untightened, so you can reuse them a handful of times without losing strength.

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.

DIN 128A—These washers have split ends that bite into your material surface for a tighter hold than other curved washers.

	ID, mm	OD, mm	Thk., mm	Overall Ht., mm	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Plated Steel



	M3.5	3.7	7.0	0.4	1.4	DIN 137A	100	000000000	00000


	Zinc-Yellow-Chromate-Plated Steel



			M3.5	3.6	6.7	0.6	1.1	DIN 128A	100	000000000	0000

Wave Spring Lock Washers

The wavy shape flexes like a spring to keep nuts and screws secure on slightly uneven surfaces. These washers add a small amount of tension to stop fasteners from backing out due to mild vibration. While they don't hold as well as other lock washers, they do grip slightly better than curved washers. They work best in electrical panels, light fixtures, and other light duty assemblies. Since these washers hold their shape when untightened, you can reuse them a handful of times without losing strength.

	No. of Waves	ID, mm	OD, mm	Thk., mm	Overall Ht., mm	Specs. Met	Pkg. Qty.		Pkg.
18-8 Stainless Steel



	M3.5	1	3.7	8.0	0.5	1.8	DIN 137B	100	000000000	000000