The standard ER collet is the most widely used clamping system in the world. Made from Alloy spring steel and fully hardened these ER collets are ideal for many machining applications including boring, milling, reaming, tapping and grinding. MariTool offers ER collet sizes starting at ER8 through ER 40 .

Collets are used to hold a tool in a central position as it rotates. As the tool is inserted into the collet, the device expands and provides uniform pressure that holds the tool in place. However, if the collet stretches too far, it cannot secure the instrument properly and may lose shape.

Most collets are round, cone-shaped, and slotted. Collets encircle the cutting tool shank to evenly distribute holding power around its center bore. As we continue to explain more about collets, it will first be helpful to understand the basic anatomy of collets and of a collet chuck system.