... in the design and manufacture of premium diamond drilling tools for the world engineering: geotechnical exploration, Mining exploration, Oil exploration and ... diamond surface-set core bit, PDC bits (core or noncoring), casing shoes, reaming shells, overshot, hoisting plug, water swiel, wrench. 1 ... .Drill rod: BQ, NQ , HQ, PQ, NT, HT Casing tube: BW, NW, HW, HWT, 2.Core barrel: BQ NQ ...