ClipArt ETC
"A ball-bearing hub with outward cups. The hub-shell H is turned out of mild steel, and the cups C are forced into the ends of the hub-shell and soldered thereto. A thin washer W is then spun into the end, for the purpose of retaining oil, and a thin internal tube T unites the two cups, and guides the oil fed in at the middle of the hub to the balls. The projecting flanges S are for the attachment of the tangent spokes used to build the hub into the wheel. The spindle A has the two cones screwed on it, one C, against the shoulder, the other C, adjustable. The-spindle ends are passed through the back-fork ends and are there adjusted in position by the chain-tension adjusters. After adjustments the nuts N clamp the spindle securely between the fork-ends. The chain-wheel or free-wheel clutch is screwed on the end of the hub-shell with a right-hand thread." — The Encyclopedia Britannica, 1910

Ball-bearing Hub

"A ball-bearing hub with outward cups. The hub-shell H is turned out of mild steel, and the cups C are…

a ball bearing is a type of rolling-element bearing which uses balls to maintain the separation between the moving parts of the bearing.

Ball Bearing

a ball bearing is a type of rolling-element bearing which uses balls to maintain the separation between…