A collet chuck is a type of clamping device used in machining to hold cylindrical workpieces securely. It consists of a collet, which is a sleeve that can expand or contract, and a chuck that provides the necessary grip. When the collet is tightened, it grips the workpiece firmly, allowing for precise machining operations. Collet chucks are commonly used in various tools, such as lathes and milling machines, due to their ability to provide high accuracy and repeatability. They are particularly useful for holding small-diameter tools and workpieces, making them popular in industries like manufacturing and metalworking.