Ball Bearings


Ball BearingsBall Bearings are a type of rolling-element bearing that uses balls to maintain the separation between the moving parts of the bearing. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. Radial Ball bearings can support moderate radial loads and moderate axial loads (parallel to the shaft). They can operate at high speeds (400,000 RPMs and higher). Ball bearings with shields or seals for protection can be lubricated to last for the operating life. Sometimes ball bearings are also called “deep groove ball bearings.” AST Bearings is the leading ball bearing supplier. 

Ball Bearing Catalog & CAD Library

Precision Ball Bearings versus High-Precision Ball Bearings

Generally speaking, precision ball bearings comply to ABEC-1 and ABEC-3 tolerances while high-precision ball bearings comply to ABEC-5, ABEC-7, or ABEC-9 tolerances. Some general purpose ball bearings intentionally do not comply to the ABEC precision tolerance specifications and are not graded nor rated as such.

Super Precision, Super High Precision, and Ultra Precision Ball Bearings

Some factories promote bearings as “Super Precision (MM),” “Super High Precision (MMV),” and “Ultra Precision (MMX)” bearings. These are all just factory defined terms to describe ABEC-7 through ABEC-9 (ISO-P4 through ISO-P2) tolerances with one of them being a compromise between the two specifications.

More specifically, precision ball bearings called Super Precision (MM) are typically manufactured to ABEC-7 (ISO-P4) tolerances. Ultra Precision (MMX) bearings are usually manufactured to ABEC-9 (ISO P-2) tolerances. However, so-called Super High Precision (MMV) bearings are manufactured partly to ABEC-7 tolerances, but also partly to tolerances defined by ABEC-9 specifications. Super High Precision bearings operate with performance levels and running accuracy meeting ABEC-9 specifications; however, their remaining features meet ABEC-7 specifications and subsequently are less expensive compared to fully compliant ABEC-9 (Ultra Precision) bearings. For more about official precision bearing tolerances and their definition by the ABMA and ANSI, please see our white paper entitled, "Bearing Tolerances and Precision Levels."

Categories of Ball Bearings Based and Load Handling Capabilities

Ball bearings are typically divided into three overall general categories depending on the direction of the loads they are designed to encounter (radial, axial, or combination of each load respectively) including:

Not All Ball Bearings Are "Radial" Ball Bearings

Most ball bearing units are radial ball bearings; however, there are other types of bearings that use balls as their rolling element which are not classified as "radial" ball bearings. These include:

Radial Ball Bearings Product Types

AST supplies ball bearings of virtually every type and they are sub-classified in the following categories. Click on each to learn more:

If you need help in selecting the best precision bearings for your particular application, please remember that design engineering and application assistance are available from AST as part of our value-added services designed to make your job easier. AST Bearings is your go-to ball bearing supplier.

Radial Ball Bearing White Papers and Articles

There are a number of technical papers on this website found in our Resource Center about radial ball bearings. Some of them are listed below:

Radial Ball Bearings Catalog Online

AST Bearings' comprehensiveball bearing catalogcontains detailed specifications and 3D CAD models for 2,173 different ball bearings in 13 categories. Click here to go to our interactive online catalog and product specifier for ball bearings including full specifications and free 3D CAD model downloads.

Ball Bearing Catalog & CAD Libraryball bearing catalog

MM/MMV tolerance class

AST Bearings is proudly presenting our new certificates for both the NJ and CA locations: AST Bearings’ ISO 9001:2015 Certificates

To learn more about what the ISO 9001 standard is, the differences between the 2015 and 2008 versions, and how AST verifies customer satisfaction: Learn About AST Bearings’ certification to ISO 9001:2015

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