Abstract
In high precision machining using a hand-operated machine tool, the human operator could perform its task well and swiftly, if it could acquire sensory information helpful to the performance effectively. In the previous paper, one of the authors described a system for active auditory feedback of minute cutting force to the human operator in small-diameter deep-hole drilling. In this paper, the authors have discussed the kind of feedback information and characterisitcs in the same system from the viewpoints of operating efficieny and the others. As the results, it is found that the envelope signal of cutting torque as the feedback information and suitable folding line feedback characteristics are superior in improvement of operating efficiency and suppression of operating load.