... Coal Mining bits,Cutter,caol cutter,mining tools,mining drilling,Mining exploitation,Conical bits,conical cutters Coal Mining bits,Cutter,coal cutter,mining tools,mining drilling,Mining exploitation,Conical bits,conical ... heat treatment with 40-44HRC hardness, has high toughness and wearable character. Tip is made from ... all the performance features such as a high feed rate, a long service life and ...