What is a collet in CNC milling?

A collet is a specialized type of tool holder used in CNC milling that is designed to securely grip the cutting tool. Its primary function is to provide a high level of precision and stability during the milling process. The design of a collet allows it to clamp down on the tool shank tightly, thus minimizing any potential movement or vibration that could affect the quality of the machined part. This ensures that the cutting tool remains in the correct position for accurate cuts, which is critical for achieving tight tolerances and high-quality finishes in CNC machining operations.

Understanding the significance of collets in the context of CNC milling highlights their role in tool setup and the overall machining process. This makes option A the most appropriate choice, as it defines a collet accurately in relation to its function as a tool holder. Other options do not describe collets accurately and pertain to other aspects of milling or machining processes.