Our ER20 collets have a capacity ranging from . 0625 - . 5000 inches or in metric sizes from 2mm up to 13mm. The number shown on the collet is the largest size that particular collet can hold, but it can be tightened to a smaller size. Purchase separately or in a set for a discounted price.

However, the collet is most often used in routers to hold the cutting bits in place. The collet is secured to the tool using a hexagonal collet nut, allowing it to be tightened or loosened to the motor arbor.

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.