Ball bearings the most widespread type of bearings. In them ball balls which slide in the racetracks executed on surfaces of outside rings (holders) are applied and are put into the stamped or mechanically processed or synthetic (polymeric) separators. Thanks to the point contact between balls and racetrack the friction moment at bearings of this kind is not big therefore they can gather big rotational speeds.
Scope of quill bearings:
As these parts are not sensitive to shock loads, can be effectively used as coupling devices in cars, milling machines, and also other machines with strong radial load. Minus of bearings is that they are rather sensitive to distortions and even the small distortion can cause its failure.
Roller bearings are the most widespread. Thanks to opportunity to maintain the hardest loadings, this type of bearings finds broad application as basic element in instrument-making and machine-building spheres.