What is the name of the piece of metal that jets out of the structure in a knife edge?

The term "knife edge" refers specifically to a thin, sharp edge of a piece of metal that extends from a structure. This design allows for precise contact with other surfaces while minimizing the area of contact, which makes it useful in various engineering applications, such as in supports for balancing or in measuring instruments where low friction is desired. The 'knife edge' is characterized by its ability to pivot or rotate about the edge, which is crucial in applications like a knife-edge balance, where it aids in accurate weight measurements. The other options represent different components or fasteners that do not capture the specific function and design of a knife edge as accurately.