Leonardo da Vinci drew a ball bearing using balls between moving surfaces to reduce friction.
His sketches show a bearing arrangement in which balls could roll between components rather than allowing one surface to slide directly against another. Rolling contact generally produces less friction than sliding contact, making the principle useful for rotating machinery.
Leonardo’s bearing drawings date from the late fifteenth century and are often cited as an early design for a modern ball bearing. They were part of his investigations into mechanics, machines, and the causes of friction. The drawings do not prove that he manufactured a standardized, durable bearing for practical industrial use.
Modern ball bearings use carefully shaped races, hardened materials, lubrication, and controlled clearances. Leonardo’s concept was therefore an important mechanical insight, but not the complete industrial bearing technology that became widespread centuries later.