A collet chuck is a type of tool holder used in machining to securely grip a rotating tool or workpiece. It consists of a cylindrical sleeve, known as a collet, which can expand or contract to hold various sizes of tools. This design allows for quick tool changes and precise alignment, making it popular in milling and drilling operations. Collet chucks are commonly used in conjunction with CNC machines and lathes, providing a reliable grip that minimizes vibration and improves accuracy. They come in different sizes and styles, accommodating various tool shapes and sizes for versatile applications in manufacturing.