Lathe chucks are a type of clamp used to hold a rotating object while you're working on it. A lathe is a tool used in disciplines like metalworking and woodturning to rotate workpieces. The chuck is the part of the tool that holds the workpiece in place and is usually attached to the lathe by a rotating spindle.
Lathe chucks are used to hold objects, often cylindrical in shape, while you're doing a task like sanding, cutting or facing. They can be used with a late chuck guard for protection. They have adjustable jaws, or dogs, which allow you to tighten the grip on the object, according to its size.
Some types of chucks require a key to tighten them, while others can only be tightened by hand. These are called keyless chucks.
You will also find lathe chucks with independently adjustable jaws to allow clamping of irregularly shaped objects.
Finally, there are lathe chucks which use flexible collars called collets, rather than jaws, for adjustment. These offer greater precision and take less time to set up, but only accommodate one workpiece size.