Chapter 415: A Bunch of Third Wheels The members of Zhang Yan's group listened, their eyes lighting up as they began a heated discussion. Cheng Lefeng raised a question. "But how can we be sure the current spindle is within the resonance range? And how do we calculate the appropriate natural frequency?" After a moment's thought, Zhou Yimin replied, "We can start with a simple vibration test using some of the existing equipment. Although the precision might not be high, it should be enough to judge…