What must the collet size match on the Router?

The correct answer is that the collet size must match the bit shank diameter. This is critical because the collet is the component that grips and holds the bit securely in place during operation. If the collet does not match the shank diameter of the bit, it can lead to insufficient clamping force, causing the bit to wobble, misalign, or even come loose while in use. This not only compromises the quality of the work being done but also poses a significant safety hazard, as a spinning bit that is not properly secured can cause injury or damage to the workpiece.

Matching the collet to the bit shank diameter ensures a tight and secure fit, allowing for controlled and precise cutting. Ensuring the correct collet size is essential for safe and effective operation when using a router and is a fundamental practice in any model shop or workshop environment.