Tapered roller bearings resemble the wide edge of a cone rather than a circle. This helps to obtain true rolling motion and ensures that the bearing can handle all loads (radial, thrust, or both) in any combination.
Ball bearings were first produced in Europe, so they were standardized to metric dimensions. American manufacturers started using steel ball bearings later, and used the metric dimensions until the early 1990's.
Many buildings on the West coast, especially in San Francisco, are built to withstand Earthquakes. The San Francisco International Airport, for example, is built with 267 columns that support the weight of the airport, and each ride on a 5-foot-diameter steel ball bearing. In the event of an Earthquake, the ground can move as much as 20 inches with no building damage.
Did you know that newspaper vending machines have ball bearings in them? Bearings are squished between a base plate and transfer plate to adjust to only allow a single newspaper to be retrieved from the machine.
Critical to improving the life and efficiency of bearings is lubrication. Grease is the most common form of lubricant, but many can use graphite, silicone or other slippery substances to keep ball bearings rolling smoothly with as little friction as possible.
Among the remains of the ships in Lake Nemi, Italy, it was recorded that a wooden ball bearing is supporting a rotating table. The wrecks date to 40 AD and is one of the earliest examples of ball bearings.
