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Technical Toolbox

Technical Definitions and Conversion Charts

Technical Definitions and Conversion Charts
  1. PDFInch>Decimal>Metric Conversion Chart (PDF - 270KB)
  2. PDFShaft and housing fits for electric motor style bearings (PDF - 446KB)
  3. PDFBarden Company engineering data for super precision bearings (PDF - 633KB)
  4. PDFClassification and Characteristics of Rolling Bearings (PDF - 1.82MB)
  5. PDFComparison of the load carrying ability of different types of bearings (PDF - 69KB)
  6. PDFInterchanges (PDF - 1.73MB)
  7. PDFHow a Ball Bearing is made (PDF - 118KB)
  8. PDFEmerson Guide to Bearing Nomenclature  (PDF - 4.33MB) 

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
Flaking

Surface of the raceway and rolling elements peels away in flakes Conspicuous hills and valleys form soon afterward
Peeling
Peeling

Patches of minute flaking or peeling. Innumerable hair-line cracks visible though not yet peeling
Spalling
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
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
Wear

The surfaces wear and dimensional deformation results. Wear is often accompanied by roughness and scratches
Speckles and Discoloration
Speckles and Discoloration

Luster of raceway surfaces is gone; surface is matted, rough, and / or evenly dimpled. Surface covered with minute dents
Indentations
Indentations / Dents and Scratches

Scoring during assembly, gouges due to hard foreign objects, and
surface denting due to mechanical shock.
Chipping
Chipping

Partial chipping of inner ring, outer ring, or rolling elements.
Cracking and Notching
Cracking and Notching

Localized flaking occurs. Little cracks or notches appear
Rust and Corrosion
Rust and Corrosion

The surface becomes either partially or fully rusted, and occasionally rust even occurs along the rolling element pitch lines
Seizing
Seizing / Seizure

The bearing heats up and becomes discolored. Eventually the bearing will seize up
Fretting and Fretting Corrosion
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
Electrical Pitting / Electrolytic Corrosion

Pits form on the raceway. The pits gradually grow into ripples.
Rolling Path Skewing
Rolling Path Skewing

Abrasion or an irregular, rolling path skewing left by rolling elements along raceway surfaces
Damage to Retainers
Damage to Retainers /
Cage Damage

Rivets break or become loose resulting in cage damage.
Creeping
Creeping

Surface becomes mirrored by sliding of inside and outside diameter surfaces. May by accompanied by discoloration or score
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