ER25 series collets have a capacity of 1mm-17mm. Each ER25 collet has a range of (1 mm). The size indicated on the collet is the largest size it can hold and can be collapsed smaller within its collapse range of (0.9mm). For example, ER25-3mm can grab a round shank from 3mm diameter to 2.1mm diameter.

Mechanical Toolholding Systems. The ER collet chuck is suitable for clamping tools with cylindrical shanks in collets in accordance with DIN ISO 15488-B. Due to the large and flexible clamping range of the collets, various shank tolerances can be clamped.

Disadvantages of collets Collets are limited in the range of workpiece sizes they can accommodate and are ideally suited for repetitive jobs where the clamping requirements don't vary greatly. They are also better suited for clamping tooling with longer shanks and workpieces with consistent diameters.

Collets Vs Jaw Chucks. Collets and chucks are two common types of mechanism used to hold spindle tooling or workpieces. Technically speaking, a collet is a type of chuck, but the two terms are usually used exclusively. A 'chuck' usually refers to any type of work holder which is not a collet.