ER Collets

ER Collets are the most commonly used Collets in the world due to their versatile range, collapsibility and affordability. They are made from High Alloy Steel and hardened to 44-48HRC. The ER Collets designed for general purpose milling and drilling with low cutting speeds and small cuts. The ER Collet is not recommended for high speed machining, high feed milling or for roughing. It can cause vibration, poor tool life and tool pull-out. The ER sealed collets are available for through coolant Drills, End Mills and any round coolant tools. The standard series include: ER-8, ER-11, ER-16, ER-20, ER-25, ER-32, ER-40, and ER-50. ER8 and ER11 Collets collapse up to 0.020” (0.5mm) smaller than the nominal collet internal size and ER16, ER20, ER25 and ER32 collapse up to 0.039” (1mm). ER50 Collets collapse up to 0.079” (2mm). The measured OD of the collet in millimeter is close to the series number. For instance, if OD is 8.5mm then it is ER8. In the same way the OD of ER11 is 11.5mm, ER16 is 17mm, ER20 is 21mm, ER25 is 26mm, ER32 is 33mm, ER40 is 41mm and ER50 is 52mm.Maple Tools stocks the full range of all the individual sizes and Sets start at ER8 through ER40 Collets including metric and imperial.