... . in China.1) Product :we specializes in manufacturing:Tricone bits,steel tooth bit,milled tooth , rock roller bit,tricone bit ... -cone drill bit ,3 cone bits,rotary bit, TCI tricone bit,PDC drill bit ,diamond core bit,bicenter bit,single cone bit ... a call) .Recommended drilling parameters of tri-cone rock bits Rock formationBit typeBit sizeDrilling weightRotary speedmminchkN/mmr/minVery softSoft Marl ...