A cam operated apparatus with a cam track and cam follower being engaged with one another, a head element such as a bit operatively connected to the cam track or cam follower means, and rotational drive means such as a motor operatively connected to the other, such that rotational drive causes reciprocal action of the head element and the width of the cam follower means is in the region of 91% to 99%, of the width of the cam track, to create a harmonic effect on the head element with low noise and increased power efficiency. Pin-in-wave and wave-in-wave arrangements are described along with tools including the cam operated apparatus.