arm carries also the cutting tool drive motor and a transmission a conventional mining machine with which the cutting tool 15 according to the present invention may be utilized may be of the type shown on page 44 or page 49 of an article entitled 34 20 jahre gewinnungs lademaschine bauart f 34 by dr z ajtay published in publications of the hungarian mining research institute 1949 1969 no 13 1970 the mining machine itself forms no part of the present invention the body 1 of cutting tool 15 is provided with cutter bit holders 2 which are welded to the body 1 and in which cutter bits 3 are held by suitable means not shown as is apparent from fig1 the body 1 is formed with steps 4 5 6 and 7 which differ in diameter and to which the cutter bit holders 2 are secured as a result the cutter bits 3 are arranged in a plurality of circular groups 41 45 in one group 46 50 in another group and 51 55 in a third group see fig2 and 3 and are provided at their ends 8 with cutting edges which in the several groups lie on circles of differing diameters q q s as is apparent from fig1 particularly from the dash dot line representation thereof the cutting edges 9 of the cutter bits are inclined in the direction of the resultant r see fig3 which is due to the velocity v r of the revolving cutter bit ends of each group and the velocity v a in which the cutting tool is fed in the direction of the arrow a because the velocity at which the cutter bit ends revolve increases with the diameter for a given speed of the cutting tool and the feeding.