... soft, abrasive, unconsolidated formations that are not effectively drilled by impregnated diamond bits. They are also recommended for use in drilling ... available rotational speeds and bit loads are insufficient to use impregnated diamond bits due to drilling equipment limitations.TSP core ... much reduced.Size Available of core bits"Q" series:AQ,BQ,NQ,HQ,PQ/AQTK,BQTK,BQ3,NQ2,NQ3,NQTT,HQ3,HQTT,PQ3,PQTTT2 ...