... CUT HOLES IN GLASS, TILES, SLATE, MARBLE ,GRANITE with ease!!! a set of 20 new diamond tiped hole ... saws (Core Bits)with case.You can cut the following size holes 4mm, 5mm, 6mm, 8mm ... IN GLASS, TILES, SLATE, MARBLE ,GRANITE with ease!!! Best used with water. THESE BITS DONOT HAVE A PILOT DRILL ... OFF. I PERSONALY USE A PIECE OF WOOD WITH THE SAME SIZE HOLE IN IT AS A GUIDE , WHICH CAN ...