... 3.Zinc Plated 4.Diamond tip Diamond hole saw core drill bit Zinc plated Diamond glass & tile hole cutter Diameter ... total length is 70mm,75mm 90mm and 95mm, Diamond Core Drill Bits, also know as Diamond Hole Saws, are ... used to drill glass,ceramics, porcelain, ceramic and porcelain tile, limestone, ... add water for lubrication.Pictures: Diamond hole saw core drill bit