ER Collet Torque Chart

Proper torque for your tool holding is an important, often ignored, or misunderstood, factor. Too little torque and you risk your bit slipping, pulling out or suffering a host of vibration related issues. Too much torque can cause accelerated wear or damage to the collet, nut, or spindle, and potentially increased runout (Total Indicated Runout).

What's the correct torque? That's a hard question to answer in less than a few hundred pages. The short, unsatisfying response is that it depends on the collet, nut, spindle, shank diameter and application. Maximum torque, rather than a recommendation, is more of a warning that damage to components beyond this point is more likely. Regardless, maximum torque is often used as the default since more torque gives higher clamping pressures and better conformance between the collet and the spindle. This ignores the issue of the collet shank diameter, where too much torque can be applied to the collet before ever reaching the MAXIMUM torque for the ER size and nut type. As such, our experience suggests that too much torque is far more common than too little, potentially leading to the issues above (especially where accurate torque wrenches are not used).

With the above in mind, below is a sortable, and filterable table to hopefully make finding the torque for the collet and nut you're using easier.

Notes:

• Be aware that the numbers below may not always be required, preferable, or even possible.
• Always make sure that your collets, nuts, and spindle are clean and free of debris before tightening (For more see: Spindle Maintenance with ColletCare).
• Always make sure that your collets are properly assembled and snapped into the nut (For more see: Working with ER Collets).
• Collets and collet nuts are consumable parts and will wear over time. Excessive wear can cause less clamping force to the tool shank and more force to the other components and/or increased runout.

While we have made every effort to insure that the information in this table is correct and based on the best available data, Think & Tinker Ltd. makes no claims regarding the applicability of the data listed below to any specific application and assumes no liability for damages or injury arising from its use.