3 7/8" OD Bearings | McMaster-Carr

Our slipperiest metal thrust bearings glide on machines with frequent starts and stops, such as conveyors. Their oil contains nonstick PTFE particles that reduce wear and heat, extending the life of your equipment. All are fabricated, lubricated, and inspected in the U.S.

841 Bearing Bronze—A balance of strength and speed makes these bearings a good choice for most applications. Also known as SAE 841 bearing bronze.

High-Load 863 Iron Copper—Iron makes these bearings harder, stronger, and more resistant to sudden starts and stops than 841 bearing bronze. However, they run at slower speeds. The increased iron content also makes them appear silver.

Synthetic Oil Base—A high-quality lubricant makes all the difference. Synthetic oil is less sensitive to temperature changes than mineral oil, so it won't get runny and leak away if the bearing heats up.

	OD	Thk.	Dynamic Thrust Load Cap. @ Speed	Base Oil	Lubricant Additive	Temp. Range, ° F	Specs. Met		Each
841 Bearing Bronze



	2 3/4"	3 7/8"	1/4"	9,800 lb. @ 30 rpm	Synthetic Oil	PTFE	-60 to 300	ASTM B438	00000000	000000


	High-Load 863 Iron Copper



			2 3/4"	3 7/8"	1/4"	6,600 lb. @ 30 rpm	Synthetic Oil	PTFE	-60 to 300	—	00000000	00000

Bearing Locknuts

Carbon Steel

With a nylon insert that grips your threaded shaft or spindle without damaging its threads, these locknuts—also called shaft nuts—hold bearings, bushings, gears, and pulleys prone to vibration tightly in place. They come as one piece, so you can easily clamp them onto your shaft or spindle. But, since they aren’t made entirely of metal, they don’t stand up to heat as well as all-metal locknuts. Slots in their sides mean you can tighten and loosen them with a spanner wrench or spanner socket. Their face is also chamfered to help keep the size and weight of your assembly at a minimum. All meet international standards for bearing locknut dimensions.

Carbon Steel—All carbon steel locknuts are strong and resist wear, though they don’t stand up to corrosion as well as 303 stainless steel locknuts.

303 Stainless Steel—303 stainless steel locknuts resist corrosion better than carbon steel locknuts but aren’t as strong. They withstand washdowns and chemicals.

Thread Spacing—When choosing your thread spacing, consider the precision of your application. The finer the threads, the more control you have when making adjustments.

	Locknuts										Sockets
	Thread						Carbon Steel		303 Stainless Steel
	Size	Spacing	OD	Wd.	Insert Max. Temp., ° F	Specs. Met		Each		Each		Each
Chamfered Face



		2.933"-12	Extra Fine	3 7/8"	21/32"	160	ANSI/ABMA 8.2	0000000	000000	0000000	0000000	00000000	0000000

Oil-Embedded Thrust Bearings

Our simplest-to-use thrust bearings, with no moving parts and no need to lubricate. Their porous surface releases oil over time, so you can install and forget them. While they run in most conditions, oil may drip away if temperatures climb too high. For extremely hot environments, consider graphite-lubricated bearings. All are fabricated, lubricated, and inspected in the U.S.

841 Bearing Bronze—A balance of strength and speed makes these bearings a good choice for most applications. Also known as SAE 841 bearing bronze.

	OD	Thk.	Dynamic Thrust Load Cap. @ Speed	Base Oil	Temp. Range, ° F		Each
841 Bearing Bronze



	2 3/4"	3 7/8"	1/4"	9,600 lb. @ 30 rpm	Synthetic Oil	-35 to 300	00000000	000000

Wide-Rim Shims

Spread loads across a wider surface area than standard shims to minimize costly wear between components. With thickness tolerances as fine as a strand of hair, these shims precisely align, space, and level components on shafts, arbors, and machinery.

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.

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

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

	OD Tolerance	Min. Hardness	Pkg. Qty.		Pkg.
Carbon Steel







	2 1/2" ID × 3 7/8" OD

	0.134"	-0.008" to 0.008"	0.01" to 0.025"	-0.01" to 0.01"	Rockwell B38	1	000000000	00000


	Zinc-Plated Carbon Steel







					2 1/2" ID × 3 7/8" OD

					0.134"	-0.008" to 0.008"	0.01" to 0.025"	-0.01" to 0.01"	Rockwell B38	1	000000000	0000

Bearing Nuts


Carbon Steel Chamfered Face	303 Stainless Steel, Chamfered Face

Often paired with spring lock washers to strengthen their hold, these bearing nuts—also known as shaft nuts—keep vibration from shifting bearings, bushings, pulleys, and gears on your threaded shaft or spindle. They have slotted sides, so you can tighten and loosen them with a spanner wrench or spanner socket.

Carbon Steel—Carbon steel bearing nuts are strong and resist wear.

303 Stainless Steel—303 stainless steel bearing nuts resist corrosion better than carbon steel. They also withstand washdowns and chemicals.

Chamfered Face—Chamfered-face bearing nuts weigh less and produce less heat than stepped-face nuts.

Thread Spacing—When choosing your thread spacing, consider the precision of your application. The finer the threads, the more control you have when making adjustments.

	Nuts								Bearing Lock Washers		Sockets
	Thread
	Size	Spacing	OD	Wd.	Specs. Met	For Lock Washer Specs. Met		Each		Each		Each
Carbon Steel







				Chamfered Face

				2.933"-12	Extra Fine	3 7/8"	19/32"	ANSI/ABMA 8.2	ANSI/ABMA 8.2	00000000	000000	000000000	00000	00000000	0000000


				303 Stainless Steel







								Chamfered Face

								2.933"-12	Extra Fine	3 7/8"	19/32"	ANSI/ABMA 8.2	ANSI/ABMA 8.2	0000000	000000	000000000	00000	00000000	000000