A bimetallic screw is made up of two metals or alloys. As the name suggests, in a bimetallic screw, two metals are fixed together. A bimetallic screw is used to increase the life of the entire screw and barrel. That is because a bimetallic screw works better than a mono-metallic screw. Bimetallic screws are made in two metals - the base material and the coating material. That is why a...