Commonly used with flat or lockwashers.
Especially useful in metal-to-metal or where heavy duty fastening is required. A machine screw, also called a stove bolt, is generally a smaller fastener threaded the entire length of its shank.1/4"-20 x 6 in Phillips Flat Machine Screw, Zinc Plated Steel, 25 PK Machine screws are used in fastening nearly all types of hard materials.