The easiest way to determine what type of collet your machine has is to measure the length and diameter of the collet. All collets have a distinctive length and diameter. Use the chart below to determine the correct collet series for your machine. If you need advice, give us a call or send us an email, and one of our specialists will help you get the best performance out of your tooling. Ensure that you have the correct size for your CNC and the router bit being used. Damaged or worn collets, as well as improperly sized collets, lead to poor tool performance and premature wear.