Roller-type or ball bearings packed in grease inside all four wheel hubs allow wheels to spin freely without generating excessive heat while supporting the weight of the vehicle. In addition ...

To some clockmakers, this is a shame, as the escapement can be an elegant and mesmerizing piece of machinery, so [Brett] brought his rolling ball escapement to the exterior of this custom clock.

On modern front- and four-wheel drive cars, wheel bearings are a set of permanently sealed, precisely machined steel ball or ...