high quality tungsten carbideDrill bits good copper brazing material Used in drilling on marble, concrete and granite ect. Diameter: ... , 310mm, 350mm, 400mm, 460mm, 500mm, 600mm, 700mm,800mm, 900mm, 1000mm.material: 40 cr steel, YG8C carbidesurface treatment: sandblastWe can supply all ...