Rock drilling tools manufacturer ProDrill manufactures high quality rock drill bits, one of the most important size for benching and long-hole drilling underground is T51 Threaded Button Bit
18 Ballistic carbide inserts T51 threaded drill bit with drop center face design, 140 mm diameter match with extension drill steels. Drop center bits (DC) are well suited for drilling straighter holes in less abrasive and less consolidated rock at a faster rate.