The tool holder is a component on the spindle of a carving machine used to clamp and secure cutting tools, also commonly referred to as a collet, chuck, or ER collet. It grips the tool shank through elastic contraction, ensuring concentricity and preventing tool vibration, wobble, or slippage. The precision of the tool holder directly impacts carving quality—higher precision results in smoother cutting surfaces, reduced tool breakage, and minimal deformation of graphics. Common specifications include ER11, ER16, ER20, etc., suitable for carving tools of varying diameters. As the core component connecting the spindle and cutting tools, it primarily serves to position, clamp, and transmit power, making it an indispensable accessory for advertising carving machines.