49.9994mm ID Bearings | McMaster-Carr

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.

Shielded—The balls are covered just enough to keep out large particles while allowing air to pass through and dissipate heat.

Sealed—The best choice for dirty environments. A barrier seals out dust so it won't gunk up or wear down the balls. However, these bearings retain the most heat since air can't flow through.

Steel—Strong and wear resistant. However, these bearings are best for dry environments since moisture will cause them to rust.

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







				Steel

				50	90	20	1	6,650	7,100	-20	230	Standard	6210	00000000	000000


				Shielded







								Steel

								50	90	20	1	6,650	7,100	-20	230	Standard	6210-2Z	00000000	00000


								50	110	27	1	13,900	6,000	-20	230	Standard	6310-2Z	00000000	00000


								Sealed







												Steel

												50	110	27	1	13,900	6,000	-20	230	Standard	6310-2RS	00000000	00000