Regular Ball Bearings

• A ball bearing involves two metal races with pressure-treated metal balls that rotate between them. A cage keeps the balls in place, which functions as a retaining bracket. The two races allow two different engine parts to rotate around each using the metal balls inside the bearing to enable the motion. Regular ball bearings work well for basic functions such as wheels, pulleys, ratchets, toys, tools, computer hard drives and wagons. They do not work well for machines that rotate at extremely high speeds and require significant performance.
  
  

Precision Ball Bearings

• Precision ball bearings come in either high-precision or precision-grade bearings. These titles tend to be a bit of marketing as bearings are actually graded by what is called an ABEC scale rather than names. Precision ball bearings use the same design as regular ball bearings, but precision ball bearings are built with very hard metal and manufactured to handle very high tolerances. Regular ball bearings would simply disintegrate under the same pressures.
  
  

ABEC Scale

• Because many ball bearing manufacturers use different names without any specific standard, terms such as "precision" or "quality" bearings don't mean much. Instead, the bearing industry abides by the Annular Bearing Engineering Committee scale, otherwise known as the ABEC scale. A bearing at ABEC level one is a basic ball bearing. Common applications could be found on a roller skate or a wagon wheel. True precision bearings reach an ABEC level between seven and nine. The high end of the scale confirms the bearing will perform under extreme tolerances without failure.
  
  

Application

• Both kinds of bearings regularly need some kind of lubrication to maintain their performance level. Dirt, gunk, moisture and grit will cause premature failure. A minor failure will cause the bearing to jam or burn. However, the higher the rotational speed, the higher the risk the bearing will shatter into pieces. Precision bearings work at such extremes that a failure will likely destroy the attached engine parts. Regular ball bearing failure will likely just mean the old bearing needs to be popped out and replaced with a new one.