Under New York law, switch-blades, pocket-knifes, and knives are more complicated than other parts of criminal law. Certain knives are unquestionably illegal. These knives include gravity knives, switchblade knives, pilum ballistic knives, metal knuckle knives, and cane swords. However, other knives, such as a pocket-knife, may not be illegal. Penal Law 260.15(4) specifically states “the possession by any person of any dagger, dirk, stiletto, dangerous knife or any other weapon, instrument, appliance or substance designed, made or adapted for use primarily as a weapon, is presumptive evidence of intent to use the same unlawfully against another.”
In taking this analysis a step further, the New York Court of Appeals (the court with the final say in the matter) defined a “dangerous knife” as an instrument that “is primarily intended for use as a weapon,” or a common utilitarian utensil “converted into a weapon,” but it also could be a common utilitarian knife unmodified or not designed as a weapon (like a kitchen knife or a 4 inch fixed blade knife), but by reason of the circumstances of possession and/or the “context of activity,” is dangerous.
Unfortunately, the state of the law is not clear except with regards to the knives which are unquestionably illegal. To illustrate the point and the ambiguity of the court’s decision, if you’re a fisherman and need a 4″ fixed-blade for gutting fish, it’s not “dangerous,” because you’re not using it as a weapon. On the other hand, if you carry the same knife in a shopping mall for no reason (or for a bad reason, like intimidation), it’s possible you are committing a crime!
Just to be safe, it’s best to leave the knife at home.