If the knife is to be 'legal' to be carried in all parts of New York State, including New York City, then the blade must be less than 4" in length. While NYS law does not impose blade length restrictions on knives, the New York City Administrative Code does. NYCAC 10-133 ("Possession of knives or instruments") states:

"b. It shall be unlawful for any person to carry on his or her person or have in such person’s possession, in any public place, street, or park any knife which has a blade length of four inches or more."

There are exceptions to this provision (in subsection "d."), but none of them apply to this build.

Bob