... in the design and manufacture of premium diamond drilling tools for the world engineering: geotechnical exploration, Mining exploration, Oil exploration ... , hoisting plug, water swiel, wrench. 1.Drill rod: BQ, NQ , HQ, PQ, NT, HT Casing tube: BW, NW, HW, HWT, 2 ... reaming shell & shoe bit (syn. and surface-set, PDC)4.Drill tool: hoisting plug, water swivel, overshot (standard,heavy duty), outer tube ...