Torque applied to the clamping nut is achieved through the inertia of the spindle and the sudden stop, similar to an impact wrench. Depending on the quality of the clamping nut used. Torque values range between 10 and 14ft-lbs. with a 2.2Kw spindle and ER20 collets, which is more than sufficient for most high speed applications and has been thoroughly tested. The high torque values published by ER collet manufacturers are “maximum” torque values that should not be exceeded. Standard Maritool clamping nuts and collets provide the highest torque values of any we have tested. However their ball bearing style clamping nuts do not perform well with the RapidChange ATC magazine.

Recommended RPM for engagement ranges between 1200 and 1500 for 2.2Kw spindles. Above 1500rpm, the added torque is negligible and could damage the magazine. To ensure longevity, we have tested it up to 2500rpm without damage.  There is no benefit to exceeding the maximum recommended RPM. 

Updated on September 5, 2023

Still looking for answers? Ask our community on Discord.