Tooth Impacts

​These two basketball players represent two milling tools. The one on the right is stiffer therefore the tool point (ball) deflects less and returns to his hand (workpiece) sooner than the one on the left. The frequency of the dribble, or the number of times it hits their hands in one minute, is lower on the left than the right. For a milling tool, the waiting for the ball to return to the hand is the tooth impacts. To get the tooth impact timing right (to prevent chatter) you either must slow the spindle speed down or reduce the number of teeth on the less stiff tool.