The most popular thread used in fastening is the machine screw thread. The machine screw thread has a 60 degree thread angle made in a continual running helix pattern. It’s primarily used with a nut or a tapped hole.
Socket screws have a machine screw thread and are made primarily in two materials, steel and stainless steel. The steel socket screws are made from an alloy steel and are heat treated to high tensile strengths. The stainless steel socket screws are generally made from 302 or 304 and are not heat treated.