Technical Toolbox

Technical Definitions and Conversion Charts

Inch>Decimal>Metric Conversion Chart (PDF - 270KB) Shaft and housing fits for electric motor style bearings (PDF - 446KB) Barden Company engineering data for super precision bearings (PDF - 633KB) An overview of bearing types and glossary of engineering terms (PDF - 1.6MB) Comparison of the load carrying ability of different types of bearings (69KB) Interchanges (PDF - 1.73MB)

Bearing Failure Analysis

The accurate diagnosis of a bearing failure is imperative to prevent repeated failures and their additional expenses. While performing failure analysis is commonly left to outside vendors, the actual collecting of information can make a great difference in correctly diagnosing a bearing failure.

Here are some common failure types. Click on an image below for details or Contact Us for assistance:

Flaking Surface of the raceway and rolling elements peels away in flakes Conspicuous hills and valleys form soon afterward	Peeling Patches of minute flaking or peeling. Innumerable hair-line cracks visible though not yet peeling	Spalling Score accompanying seizing. Mounting score in axial direction. Scores on roller end face and guide rib-cycloidal scores. Scratches in spinning direction on raceway surface and rolling contact surfaces	Smearing and Scuffing The surface becomes rough and some small deposits form. Scuffing generally refers to roughness on the race collar and the ends of the rollers
Wear The surfaces wear and dimensional deformation results. Wear is often accompanied by roughness and scratches	Speckles and Discoloration Luster of raceway surfaces is gone; surface is matted, rough, and / or evenly dimpled. Surface covered with minute dents	Indentations / Dents and Scratches Scoring during assembly, gouges due to hard foreign objects, and surface denting due to mechanical shock.	Chipping Partial chipping of inner ring, outer ring, or rolling elements.
Cracking and Notching Localized flaking occurs. Little cracks or notches appear	Rust and Corrosion The surface becomes either partially or fully rusted, and occasionally rust even occurs along the rolling element pitch lines	Seizing / Seizure The bearing heats up and becomes discolored. Eventually the bearing will seize up	Fretting and Fretting Corrosion There are two types of fretting. In one, a rusty wear powder forms on the mating surfaces. In the other, brinelling indentations form on the raceway at the rolling element pitch
Electrical Pitting / Electrolytic Corrosion Pits form on the raceway. The pits gradually grow into ripples.	Rolling Path Skewing Abrasion or an irregular, rolling path skewing left by rolling elements along raceway surfaces	Damage to Retainers / Cage Damage Rivets break or become loose resulting in cage damage.	Creeping Surface becomes mirrored by sliding of inside and outside diameter surfaces. May by accompanied by discoloration or score