What is a High Torque Retention Knob?JM's High Torque retention knobs have a unique, newly-patented design that prevents toolholder distortion. When a toolholder is distorted it will not fit properly in the spindle. An expanded toolholder is free to move in the spindle causing excessive harmonics, damage to the toolholder and spindle, and poor tool life. High Torque retention knobs are longer than a traditional retention knob, but share the same head dimensions. The additional length also increases durability of the retention knob; a standard knob has less shank elasticity and will fatigue faster. The extra length of the knob is added to the shank of the knob below the flange. This relief, along with a precision pilot and controlled threads, allows for the stress to be distributed into a deeper cross-section of the toolholder where it has more resistance. (US Patent # 8.998.545 B2 Japan Patent # 5675649)