1/4" Diamond Core Bits, pack of 3, for glass and tile. Free instruction guide for beginners. Drill glass, tile and porcelain. These bits have a 1 " shank and fit almost any hand drill or drill press. Ideal for drilling wine bottles and glass block. Simple, Easy to Use, Beginner's drilling instructions show you how. All you need is your drill, the diamond drill bits. It's an easy decision.