9BA= 1.9MM 64.94TPI P=.391 TAP=1.55MM

A machine screw is a fully threaded fastener designed to be used with a pre-tapped hole or a matching nut. Unlike wood screws, machine screws have a uniform diameter along the entire length and are typically used in metal, machinery, and equipment assembly. They are available in various head styles and drive types to suit different applications.