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.

Spring collets are perishable tools for fixing a workpiece at the processing, or fixing cutting tools, and used as some parts of a machine or a conveyance machine.

ER collets have a wide clamping range and high accuracy. While they are designed for tool holding, they work great for work holding in small lathes. With a full set of ER collets you can hold any diameter that is in the clamping range of the set. There are several types of collets that look like ER collets.