3 1/8" Housing ID Bearings

Support complex movement in multiple directions with a single compact bearing. The balls distribute weight at four points, so these bearings handle radial, thrust, and moment loads all at once. For example, you’ll often find them in robot arms, which rotate, extend, and twist while supporting an object’s weight. Thinner than two standard angular contact ball bearings paired together, these bearings squeeze into tight spaces. They’re commonly paired with large hollow shafts to run electrical wire and other lines.

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

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.

					Dynamic Load Cap.					Temp. Range, ° F
	For Shaft Dia.	For Housing ID	Wd.	ABEC Rating	Radial, lb.	Thrust, lb.	Moment, ft·lbf	Max. Rotation Speed, rpm	Contact Angle	Min.	Max.	Inner Ring Type		Each
Open







				Steel

				2 1/2"	3 1/8"	5/16"	1F	840	1,250	70	1,200	30°	-60	250	Standard	6656K21	0000000

Oil-Embedded Sleeve Bearings

Install and forget these self-lubricating bearings. All are made from porous metal and saturated with oil to reduce maintenance and downtime. A good all-around choice, they are used in everything from palm-sized fans in electronics to tire-sized pulleys. Although these bearings will work in most conditions, oil may drip away if temperatures get too high. Consider a graphite-lubricated bearing for higher temperatures or places where you can’t afford the mess. All are fabricated, lubricated, and inspected in the U.S.

With no moving parts, sleeve bearings are the simplest way to support the load of a rotating shaft while reducing friction. Also known as plain bearings.

841 Bearing Bronze—A classic choice for a starter pick. Also known as SAE 841 bearings.

Mineral Oil Base—Mineral oil consistently lubricates at most temperatures but doesn’t last as long as synthetic oil.

	For Housing ID	Lg.	Dynamic Radial Load Cap. @ Speed	Base Oil	Temp. Range, ° F		Each
841 Bearing Bronze



	2 3/4"	3 1/8"	2 3/4"	15,100 lb. @ 30 rpm	Mineral Oil	10 to 220	6391K892	000000


	2 3/4"	3 1/8"	4"	22,000 lb. @ 30 rpm	Mineral Oil	10 to 220	6391K893	000000