... line core bits for various types of stone Drill: Step Drill Core Bit for Water Drilling:-Fast, clean and ... to Ø127mm(2). Shank/Top: Round, Trigonal, Hex (3). Diamond grit: D427, D252, D181 and cutting thickness ... bag; Blister; or as your requirement (6). Used to drill marble, ceramics, porcelain, tile, glass, fiberglass, quartz, ... with or without center pin. Drill: Step Drill Core Bit for Water Drilling