✕DO NOT FORCE THE FIT
- Drywall, rigid foam, and any cut that wants stiffness under hand pressure — the 9mm blade bows where the 18mm (42047) holds a line; board work is the wide blade's job.
- Leveraged cutting into wood and abusive or cold-weather work, where a thin snap segment cracks and a backed trapezoid blade (42020/42083) is correct.
- All-day professional cutting with constant extension changes, where the wear on an unlined polystyrene slide and the single included blade both start to tell — that is the working-build 42045's territory, stated plainly.
- Carton work under a written safety program (Switchblades 42060/42065), and brittle-sheet scoring (45730), are outside the whole snap-off class.