Tool holders are devices used to securely hold cutting tools in place during machining operations. They ensure precise alignment and stability, which is crucial for achieving accurate cuts and maintaining the quality of the workpiece. Tool holders come in various types, including collet chucks, end mill holders, and tool holders for lathes, each designed for specific applications. These holders are typically made from durable materials like steel or aluminum to withstand the forces generated during machining. Proper selection and maintenance of tool holders can significantly enhance the performance and lifespan of both the tools and the machines they are used with.