Bearing Tips


What is Bearing?

A bearing is defined ``as a part of a machine that allows one part to rotate or move in contact with another part with as little friction as possible".  Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can handle.  Additional functions include the transmission of loads and enabling the accurate location of components.  A bearing may have to sustain severe static as well as cyclic loads while serving reliably in difficult environments.


Housing Type

  1. Cast Iron – one piece cast iron housing provides solid construction and maximum wear resistance
  2. Ductile Iron – one piece ductile iron housing is made to the same exacting standards as cast iron housing with the addition of higher tensile strength values.
  3. Pressed Steel – various gauges are available for lighter load applications
  4. Stainless Steel – solid mounting surfaces make them ideally suited for food and chemical applications.  Incorporate all the same machined features as the cast and ductile housings such as bearing seat, bolt holes and consistent mounting heights.


Locking Mechanism of the bearing to the shaft

  1. Set-screw locking
  1. most popular type of the mounted unit for pillow block bearings
  2. an extended inner ring with 2 set screws
  3. high frequency annealed areas around the set screws help eliminate cracking of the inner ring when tightening


  1. Eccentric locking collar
  1. designed for use in applications where the shafts rotate in a single direction
  2. matching angles between the inner ring and locking collar provide optimal contact and security



The outer ring of the self-contained ball bearing is ground to a sphere, and the bore of the housing is machined to a matching radius which permits for self-alignment between the two members and compensates for alignment errors or flexing of the shaft when the bearing is in operation.


Anti-Rotation Device

  1. prevents the bearing outer ring from rotation in the housing
  2. anti-rotation pin is standard on wide inner ring bearings and an option on flush back inner ring bearings
  3. no interference from the self-aligning capability of the assembly since it is located in the housing loading slot


Handling of bearings

Self-sealed bearings used in mounted housing units are pre-lubricated with high quality grease.It is recommended to keep all components intact until ready to install, to protect the bearings from contamination of grease and damage during shipping and handling.


Nomenclature for ball bearings supplied by Prime Bearing



Nomenclature - for Mounted ball bearings supplied by Prime Bearing


Types of rolling contact bearings

Deep groove bearing: balls fit well into the deep grooves, enabling the bearing to sustain moderate axial loads in both directions in addition to radial loads. The bearing illustrated here has a single row of balls.

Thrust ball bearing: can support an axial load in one direction. Not designed to accommodate radial loads. The bearing components can easily be separated.  Barstools and Lazy Susan turntables use this type of bearing.

Tapered roller bearing: Both of the rings and the rollers are tapered in order to simultaneously support axial and radial loads. The ratio of the loads supported depends on the angle between the roller and bearing axes. A greater angle helps support a larger axial load.

Self-aligning ball bearing: two sets of balls run on a pair of grooves on the inner ring, with a single outer-ring concave surface, allowing the bearing to accommodate misalignment of the shaft.

Angular contact ball bearing: This particular design of angular contact ball bearing is able to accommodate a large thrust load in one direction, in addition to radial loads.

Needle roller bearing: This has long and thin rollers - the design is suited for applications where radial space is limited.

Spherical roller bearing: Because of the angular contact between the rollers and raceways, the bearing is able to accommodate both axial and radial loads; the double set of rollers also permits the bearing to accommodate shaft misalignment.  The rollers are not cylindrical, and hence the adjective `spherical'.

Cylindrical roller bearing: The cylindrical rollers are able to accommodate large radial loads. This is a single-row bearing.