... hard, crisp, debris, slipping type of rocks and ferroconcrete. Drill bit standard: Q series, T series, nonferrous metal metallurgy standard ... Full spec. Series of product can be provided. Electroplated drill bits are also available for better performance in engineering reconnaissance ... BQ3,NQ,HQPQ,PQ3 NQ/HQ Impregnated diamond core bit/Electroplated Diamond Core Drill Bit/Surface set diamond core bits