TORK CRAFT Glass Cutter (Tungsten Carbide Wheel)

A glass cutter is a tool used to make a shallow score on one surface of a piece of glass that is to be broken into two pieces. The scoring makes a split in the surface of the glass which encourages the glass to break along the score. Regular, annealed glass can be broken apart this way but not tempered glass, since it shatters rather than breaking cleanly into two pieces.