(under subclass 29) Apparatus in which the cutter comprises (1) a flexible, cable-like element which directly contacts the hard material to break it down or (2) a flexible, cable-like element which carries separate cutter teeth which directly contact the hard material, the portion of the hard material being cut being situated between guides over which the flexible cable element is drawn and the portion of the cable between said guides being effectively shortened in length as the cutting proceeds.
