3.8 mm Shims | McMaster-Carr

					Thk., mm
	For Screw Size	ID, mm	Lg., mm	Wd., mm	(A)	(B)	Hardness	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Plated Steel


		M8	9.0	22.0	22.0	3.8	2.0	Rockwell B56	DIN 434	10	000000000	000000
		M10	11.0	22.0	22.0	3.8	2.0	Rockwell B56	DIN 434	10	000000000	00000

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.

Blue-Dyed Steel—These metric-sized washers have a distinctive blue color, so you can easily tell them apart from inch washers. The coating provides only minimal corrosion resistance, so these washers are best for dry environments.

	ID, mm	OD, mm	Thk., mm	Specs. Met	Pkg. Qty.		Pkg.
Blue-Dyed Steel


	M12	12.3	21.7	3.8	ASME B18.21.2M	100	000000000	000000

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.

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.

High-Strength 17-7 PH Stainless Steel—The strongest stainless steel washers we offer, these are comparable to high-strength Grade 8 steel. They won’t rust in wet and outdoor environments, but they can’t handle the harsh chemicals that 316 stainless steel can.

	ID, mm	OD, mm	Thk., mm	Overall Ht., mm	Pkg. Qty.		Pkg.
High-Strength 17-7 PH Stainless Steel


	M16	16.1	38.7	3.8	5.7	1	000000000	00000

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.

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

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

	No. of Waves	ID, mm	OD, mm	Thk., mm	Overall Ht., mm	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Plated Steel


	M24	1	24.5	40.0	3.8	6.5	DIN 128B	5	000000000	000000

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.

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.

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.

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.
18-8 Stainless Steel


	M24	24.5	40.0	3.8	6.5	DIN 128A	5	000000000	000000

	Zinc-Plated Steel


			M24	24.5	40.0	3.8	6.5	DIN 128A	10	000000000	00000

			Black-Oxide Steel


					M24	24.5	40.0	3.8	6.5	DIN 128A	5	000000000	00000