Main types of wood screws

Common wood screws are made of iron and copper. They are classified into round head, flat head, and oval head according to the different nail heads. There are two types of nail heads: slotted screws and cross head screws. Generally, round head screws are made of mild steel and are blue. Flat head screws are polished. Oval head screws are usually cadmium-chrome plated. They are often used to install hinges, hooks and other hardware accessories. The specifications are determined by the diameter, length and nail head type of the rod.