CUTTING TOOL INTEGRATED IN A DRILLSTRING
The present invention discloses a cutting tool integrated in a drillstring for enlarging a borehole, where the cutting tool at least comprises: one or more side mills (12, 13, 14) arranged along the axis of said drillstring in a reamer housing (11), where the side mills (12, 13,14) are adapted to be rotated relative to the tool housing (11) by individual driving means. The self driven rotational side mills may be dome shaped cones where expand radially out of the reamer housing (11), or may be a special non-circular dome shaped cones where rotates without expanding.