paul wheaton wrote:Wouldn't the little balls fall out?
It wont..actually there will be partially hemispherical grooves(like sockets) in both the inner & outer, with some little tolerance that the small balls can rotate freely but not fall off(like a prison/cage).
..and of course there would be grease not for holding the balls at places, but for lubrication - without lub the hemispheres/little balls may get worn out soon due to excessive rotational friction.
Hope I'm not going in too technical.
Have you ever wondered how we sit static in a car/a bike while the base is rotating? You are actually sitting over rolling tyres. Can anyone place an object over a rolling object? Will it stay there? Bearings(is what we call) makes it possible. It makes one part(tyres) roll relative to another part(the chassis). Bearings use almost the very same principle.
Believe me...I've got a Bachelor in Mech!