Razor blades, while possessing an exceptionally sharp edge, are generally unsuitable for use as knives. Their primary design prioritizes achieving a close shave by delicately slicing hair. This necessitates a thin, flexible blade made of hardened steel. In contrast, a knife requires a robust and durable blade capable of withstanding significant force and repeated use in cutting, slicing, and prying. A typical utility knife or kitchen knife, for instance, is significantly thicker and more rigid than a razor blade.
The limitations of razor blades as knives extend beyond their physical construction. Their inherent fragility makes them prone to snapping or bending under pressure. This presents a significant safety risk to the user. Furthermore, the small size and shape of most razor blades offer a limited grip and control, making precise cutting tasks difficult. The absence of a substantial handle, common in purpose-built knives, further reduces usability and increases the likelihood of accidental injury. Historically, tools intended for cutting tough materials have consistently prioritized strength and control over extreme sharpness alone, explaining the development of distinct knife designs.