What is a lathe chuck and what are the types of chuck?
Workholding is a company that sells chucks and has an article with pictures. A link is provided to the site. Additional links are provided to other images. Be sure to at least look at the “6-jaw chuck taken apart” to see the scroll gear that simultaneously closes the jaws. Look closely. The shiney “circles” are not circles at all but are the gradually shaped spiral of the scroll.