3/8" Shims | McMaster-Carr

Slip these shims around existing mounting fasteners to precisely align and level components such as pumps, compressors, and gearboxes with motors, all without disassembling them. They’re also good for leveling machines on uneven surfaces. To reduce sizing errors, these shims are either labeled with their thickness so there's no need to measure or color coded by thickness to quickly spot the right size.

You can stack multiple shims to achieve your exact thickness, but stacking more than four may cause them to shift. Remember, fewer shims are better, so a couple of thicker shims are more stable than a bunch of thin shims.

18-8 Stainless Steel—The choice for wet and outdoor environments, these shims resist rust. However, they’ll corrode or pit when exposed to salt water and chemicals.

Insertion Tools—Ease shim insertion and removal, keeping your fingers clear in the process.

	Shims											Insertion Tools
				Slot						Each
	Thk.	Thk. Tolerance	For Max. Screw Size	Wd.	Dp.	Min. Hardness	Identification Type	End Shape		1-9	10-Up		Each
18-8 Stainless Steel





				1 1/2" Lg. × 1 1/2" Wd. (Shim Trade Size AA)

				0.375"	-0.01" to 0.01"	3/8"	7/16"	61/64"	Rockwell B85	Labeled	Tab	97235K665	000000	000000	97235K9	00000




						2" Lg. × 2" Wd. (Shim Trade Size A)

						0.375"	-0.01" to 0.01"	1/2"	9/16"	1 9/32"	Rockwell B85	Labeled	Tab	9722K116	00000	00000	97235K915	0000




								2 1/2" Lg. × 2 1/2" Wd. (Shim Trade Size BB)

								0.375"	-0.01" to 0.01"	5/8"	11/16"	1 19/32"	Rockwell B85	Labeled	Tab	97235K349	00000	00000	97235K915	0000




										3" Lg. × 3" Wd. (Shim Trade Size B)

										0.375"	-0.01" to 0.01"	3/4"	13/16"	1 29/32"	Rockwell B85	Labeled	Tab	9722K122	00000	00000	97235K93	0000




												4" Lg. × 4" Wd. (Shim Trade Size C)

												0.375"	-0.01" to 0.01"	1 1/8"	1 3/16"	2 19/32"	Rockwell B85	Labeled	Tab	9722K126	00000	00000	97235K93	0000




														5" Lg. × 5" Wd. (Shim Trade Size D)

														0.375"	-0.01" to 0.01"	1 1/2"	1 9/16"	3 9/32"	Rockwell B85	Labeled	Tab	9722K133	00000	00000	97235K945	0000




																6" Lg. × 6" Wd. (Shim Trade Size E)

																0.375"	-0.01" to 0.01"	1 7/8"	1 15/16"	4"	Rockwell B85	Labeled	Tab	97235K63	00000	00000	97235K96	0000




																		6" Lg. × 6" Wd. (Shim Trade Size G)

																		0.375"	-0.01" to 0.01"	2 1/4"	2 5/16"	4 3/16"	Rockwell B85	Labeled	Tab	97235K64	00000	00000	97235K96	0000




																				8" Lg. × 8" Wd. (Shim Trade Size H)

																				0.375"	-0.01" to 0.01"	2 1/4"	2 5/16"	5 3/16"	Rockwell B85	Labeled	Tab	97235K65	00000	00000	97235K985	0000

Large-Adjust Slotted Shims


Round End	Square End

Best for filling large gaps, these thick shims are commonly used to align cabinets, doors, and windows. Slip them around existing mounting fasteners without unfastening them. All are made of plastic to resist moisture and prevent rot. To reduce sizing errors, these shims are color coded by thickness to quickly spot and grab the right size every time.

				Slot
	Thk.	Thk. Tolerance	For Max. Screw Size	Wd.	Dp.	Material	Color	End Shape	Pkg. Qty.		Pkg.
3" Lg. × 2 5/16" Wd.



		0.375"	-0.032" to 0.032"	3/4"	3/4"	2 1/4"	Polypropylene	White	Round	10	9731K462	00000


		3 1/2" Lg. × 1 1/2" Wd.



				0.375"	-0.032" to 0.032"	1/2"	1/2"	3"	ABS	White	Round	10	9731K461	0000


				4" Lg. × 3" Wd.



						0.375"	-0.03" to 0.03"	7/8"	29/32"	2 7/8"	Polypropylene	White	Square	5	90513A106	0000


						6" Lg. × 4" Wd.



								0.375"	-0.03" to 0.03"	3/4"	51/64"	4 61/64"	ABS	White	Square	1	9303K715	0000

Breakaway Rectangular Shims

Make size adjustments easy with these scored shims—just break off pieces for a custom fit around fasteners or corners. Designed to fill wide gaps, they’re best for aligning cabinets, doors, and windows. All are made of plastic to resist moisture and prevent rot.

									Pkg.
	Thk.	Thk. Tolerance	Score Interval	Color	Material	Specs. Met	Pkg. Qty.		1-4	5-Up
5" Lg. × 5" Wd.



		0.375"	-0.03" to 0.03"	1" × 1"	Black	ABS	ASTM D785	5	95015K46	000000	000000

Leveling Washers for I-Beams

Mounted

on an

I-Beam

Commonly called beveled washers, these are tapered to fit inside an I-beam's flange to provide a parallel bearing surface.

18-8 Stainless Steel—18-8 stainless steel washers have good chemical resistance and may be mildly magnetic. These washers are the most corrosion-resistant option.

				Thk.
	For Screw Size	ID	Wd.	(A)	(B)	Hardness	Pkg. Qty.		Pkg.
18-8 Stainless Steel



		5/8"	0.688"	1.500"	0.375"	0.125"	Rockwell B45	1	90845A039	000000

Mil. Spec. Split Lock Washers

These washers are manufactured and tested to strict U.S. military standards for material and construction. As you tighten, the uneven ends bite into the nut or screw so it won't loosen due to mild vibration. While they don't hold as tightly 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.

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

	ID	OD	Thk.	Mil. Spec.	Specs. Met	Pkg. Qty.		Pkg.
Zinc-Yellow-Chromate-Plated Steel



	1 1/2"	1.504"	2.419"	0.375"	MS35338-57	ASME B18.21.1	1	91475A376	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.

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.

Super-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.

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.

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

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



	1 1/2"	1.534"	2.419"	0.375"	ASME B18.21.1	1	92146A041	00000


	Super-Corrosion-Resistant 316 Stainless Steel



			1 1/2"	1.534"	2.419"	0.375"	ASME B18.21.1	1	92147A041	00000


			Zinc-Plated Steel



					1 1/2"	1.534"	2.419"	0.375"	ASME B18.21.1	1	91102A041	0000


					Black-Oxide Steel



							1 1/2"	1.534"	2.419"	0.375"	ASME B18.21.1	1	5185N125	00000


							Steel



									1 1/2"	1.534"	2.419"	0.375"	ASME B18.21.1	5	91101A041	00000

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.

Super-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.

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

	ID	OD	Thk.	Specs. Met	Pkg. Qty.		Pkg.
Super-Corrosion-Resistant 316 Stainless Steel



	1 1/2"	1.534"	2.159"	0.375"	ASME B18.21.1	1	94241A380	000000


	Steel



			1 1/2"	1.534"	2.159"	0.375"	ASME B18.21.1	5	90073A042	00000