Leonardo da Vinci helped develop the ball bearing with a ring of rolling balls between surfaces.
His notebooks include a bearing concept in which balls are separated so they do not collide and can roll around a track. This arrangement reduces sliding friction between rotating parts. Leonardo was interested in bearings because complex machines needed shafts and axles to turn smoothly and reliably.
The surviving drawing is often dated to around 1498. It is important as an early recorded design, but Leonardo did not invent every form of bearing, and earlier civilizations used simpler low-friction supports. Modern ball bearings developed much later through advances in precision manufacturing, hardened steel, lubrication, and standardized races.
A common mistake is to treat Leonardo’s sketch as a ready-to-install modern bearing. His design lacked the industrial production methods needed for accurate, durable components. Nevertheless, the idea of using rolling elements to separate moving surfaces is the central principle behind the ball bearings used in machinery, vehicles, and tools today.