Our casing tubes are all manufactured by CNC machines, and ... -heat treat,BW NW HW HW China Drilling Geological Equipment ltd., is the main professional manufacturer of drilling tool ... diamond surface-set core bit, PDC bits (core or noncoring), casing shoes, reaming shells, overshot, hoisting plug, water swiel, wrench ... rod: BQ, NQ , HQ, PHD, BT, NT, HT casing tube: BW, NW, HW, HWT2.Core barrel: BQ,NQ,HQ ...