カッティング
breaking
Japanese: 割り
Applying force to a score to create a crack and break the glass into pieces.
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Breaking is the process of applying force to scored glass to split it into two pieces along the score line. There are several methods, including using running pliers, breaking pliers, and the two-handed thumb break (pushing with the thumbs). By applying force with the image of the glass “opening” beyond the score line, you can achieve a clean break along the score line.
The most common mistakes when breaking glass are “off-score breaks,” where the break occurs away from the score line, and “incomplete breaks,” where the break stops midway. Off-target breaks occur when the score is of poor quality (too shallow or broken) or when force is applied at an incorrect angle. Before breaking the glass, support it evenly and make sure to apply even pressure centered on the score line. Placing a paper template or a cloth underneath will help stabilize the glass.
Related Concepts
Running pliers are ideal for precisely running a groove from the edge of a score. Double-jaw pliers are best suited for splitting small pieces or scraps.
This entry is written in Japanese by Rei Chikaoka and translated for readers outside Japan. If something reads oddly, the original is the source of truth.