Often, when bearings are discussed, people call them ball bearings. In truth, there are several other types of bearings that don’t even use balls. The most common of these is a roller bearing. Also a misnomer is when people refer to the balls in bearings as ball bearings. The balls are just a component of a ball bearing, which may also contain an outer race, an inner race and a retainer (cage). This discussion is all about the balls used in ball bearings.
Have you ever wondered how the balls are made? Although they look simple and are an uncomplicated shape, the production process and requirements are a bit more challenging. Balls can be made from a variety of materials, including (but not limited to) tool steel, stainless, brass/bronze, titanium, Stellite, Teflon, and even ceramics such as aluminum oxide and silicon nitride. The material is chosen based on the application of the bearing.