7mm Diamond Dry Cutting Drill Bit. Professional standard tile cutting drill bit for dry drilling for tiles. High class diamonds provide ultra fast drilling speeds. Diamond Drill Bit for cutting tiles: Suitable drill bit for cutting ceramic tiles, porcelain tiles, sandstone, limestone and granite. Diamond dry cutting drill for wall tile and floor tiles. Average lifespan of this drill bit is approximately 40 holes. Use on full speed for longer life and best. Order online and get your tile drill bit delivered within Ireland in 2/3 working days.