Ball Bearing

The Torrington Company of Torrington, Connecticut manufactured this sealed bearing during the 1950s. Sealed bearings were often used in aircraft or other adverse conditions where exposing the bearing to the elements would lessen its effectiveness. The bearing is inscribed “4DR9.” The Anti Friction Bearing Manufacturers Association collected bearings for a public relations exhibit during the early 1950s, and donated them to the museum in 1977.
Simple bearings have been used for thousands of years reducing friction on turning parts like the axles of carts. In the late 1800s and early 1900s advances in machining and production expanded bearing use in all types of machines greatly increasing their life and precision. Bearings reduce friction on turning surfaces and keep them running true. Bearings come in a variety of shapes and sizes (including ball, roller, tapered, and simple friction). Modern bearings are often set in an inner and outer ring (called a race) sometimes with cages (separators) spacing the bearings. Changes to the size, shape, alignment, race, and cage allow for bearings to be used in almost any industry—from industrial turbines and automobiles to household mixers and computer hard drives.
Currently not on view
overall: 1/2 in x 5/8 in; 1.27 cm x 1.5875 cm
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Work and Industry: Mechanical and Civil Engineering
Industry & Manufacturing
Data Source
National Museum of American History


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