... drilling, tunnel drilling and shallow engineering drilling. AQ,BQ,BQ3,NQ,HQPQ,PQ3Double tube impregnated diamond core bitΦ46,Φ56,Φ ... and reaming shellΦ56,Φ59,Φ75,Φ91,Φ95 AQ,BQ,BQ3,NQ,HQPQ,PQ3Electroplated diamond core bit description: ModelRegular sizesSuited ... ,Φ75,Φ91,Φ95 AQ,BQ,BQ3,NQ,HQPQ,PQ3 NQ/HQ Impregnated diamond core bit/Electroplated Diamond Core Drill Bit/Surface set diamond ...