I'm lmao at the people suggest that string breakers are merely shankers. Simply not true.
The argument that Pro's don't break strings is completely non-sensical. They switch frames into new strings every 9ish games, ie when new balls are used. They simply have to last 9 games. If you've ever watched a good D1 player, or higher in practice, they can, and do, break strings every 60 to 120 minutes. Watch Fed at a practice session. He can go through 4 to 6 frames.
I'm a string breaker. I never break the string in an off main.. ie from a shank. It's always one of the 2 center mains. I'm not an exceptionally heavy server. I do have an exceptionally heavy baseline ball from both sides.. I'm a one handed backhander. Being 1HBH I generate more spin that most 2 handers do on that side at my level.
Strings break from a combination of an open frame (which I love) and heavy spin which induces exceptional main string movement. The crosses saw into and notch mains like a saw into a log. This sawing motion is where the breakage comes from. Its not from smashing the ball hard.
Some people don't have the technique to create this string movement. They simply assume it comes from off center shots. This is not true.