638 Bearings | McMaster-Carr

Install and forget these self-lubricating bearings. Their lubricant is a solid material that fills the space between the balls and releases oil over time, so you'll never need to add more.

Open—With no rubber seal to block airflow, these bearings dissipate heat quickly, extending the life of the lubricant and reducing friction over time.

Corrosion-Resistant 440C Stainless Steel—Combine the strength of steel with the corrosion resistance of stainless steel. These bearings won't degrade from water or mild chemicals, such as the ammonia in cleaning solutions. However, they'll weaken when exposed to salt water and harsh chemicals, such as bleach.

ABEC Rating—Bearings with an ABEC rating meet industry tolerance standards established by the Annular Bearing Engineers Committee (ABEC). They're rated on a scale from 1 to 9. The higher the rating, the tighter the tolerance. Bearings rated ABEC 1 or 3 are precise enough for most applications. If your application consistently runs at high speeds or requires high accuracy, consider bearings rated ABEC 5 or higher, since they generate less friction and heat.

							Temp. Range, ° F
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	ABEC Rating	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Min.	Max.	Inner Ring Type	Bearing Trade No.		Each
Open







				Corrosion-Resistant 440C Stainless Steel

				8	28	9	1	1,000	16,000	-10	200	Standard	638	00000000	000000

Ball Bearings

Open

Smoother than smooth—the balls inside these bearings roll nearly friction-free. You’ll often find them on rapidly rotating parts, from the whirring chuck on a power drill to the spinning shaft on an electric motor.

Open—With no rubber seal to block airflow, these bearings dissipate heat quickly, extending the life of the lubricant and reducing friction over time.

Highly-Corrosion-Resistant 316 Stainless Steel—The most corrosion-resistant metal bearings we offer. They won't pit or weaken from salt water or harsh chemicals, such as bleach and chlorine found in cleaning solutions.

							Temp. Range, ° F
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	ABEC Rating	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Min.	Max.	Inner Ring Type	Bearing Trade No.		Each
Open







				Highly-Corrosion-Resistant 316 Stainless Steel

				8	28	9	Not Rated	160	1,140	-40	140	Standard	638	00000000	000000

Dry-Running Ball Bearings

Made of naturally slippery plastic so there's no lubricant to maintain or make a mess. These bearings are ideal for spic-and-span spaces since oil won't drip off, wash out, or collect dust over time. They won't rust or warp from moisture, so they stand up to thorough cleanings.

Open—With no rubber seal to block airflow, these bearings dissipate heat quickly, reducing wear and extending the life of the bearing.

Acetal—The most common choice for plastic bearings, acetal is economical yet still stands up to daily wear and tear.

316 Stainless Steel Balls—Won't corrode from salt water or harsh chemicals, such as bleach and chlorine found in cleaning solutions.

						Temp. Range, ° F				316 Stainless Steel Balls
	For Shaft Dia., mm	For Housing ID, mm	Wd., mm	Dynamic Radial Load Cap., lb.	Max. Rotation Speed, rpm	Min.	Max.	ABEC Rating	Bearing Trade No.		Each
Open







				Acetal

				8	28	9	55	1,100	-40	180	Not Rated	638	00000000	000000