Bearings can be found all around us. There are 100 to 150 bearings in a typical car. Without bearings, the wheels would rattle, the transmission gear teeth wouldn’t be able to mesh, and the car wouldn’t run. Bearings enhance the functionality of machinery and help to save energy.
The word “bearing” incorporates the meaning of “to bear,” in the sense of “to support,” and “to carry a burden.” This refers to the fact that bearings support and carry the burden of revolving axles and shafts. Bearings reduce friction and allow the efficient transmission of power.
For several hundred years, bearings were manufactured of Lignum Vitae, a very heavy, hard, naturally oily wood native to Central America and the West Indies. The natural oils in this wood assisted in the manufacturing process by acting as a cutting fluid. These bearings are best known for “wet” applications such as propeller driven vessels, water wheels, and pumps. Wooden bearings were known to be long wearing, strong, readily available, and easy to replace. They were lubricated with tallow or other animal fats.
In the 1700s, lubricated iron became more popular and replaced wood bearings in many factories.
Isaac Babbit invented an antifriction alloy with a low melt temperature in 1839. This alloy could be formed and molded to produce an ideal surface for bearings.
In the latter half of the 1800s, steel became widely used in bearing and machinery manufacturing.
The inventions of the 1900s saw bearings become more significant to production lines. New materials have enabled us to produce bearings at less cost to the consumer. Materials used in bearings are also used in common everyday living. One example is polytetrafluoroethylene, commonly known as PTFE, the nonstick coating in many pots and pans. Bearings are now made with a variety of metals, plastics, and, in some cases, wood is still in use.