A Cap screw is a threaded fastener used to make mechanical connections between mating objects. They can be used in a wide variety of applications, ranging from manufacturing to construction, and are available in many different types and sizes. They are made from metals or alloys that offer a combination of strength, corrosion resistance, and other properties, depending on the environments and stresses they will be subject to.
The head of a Cap screw is shaped to allow the use of a tool to tighten or loosen it, and they often feature an enlarged section that acts as a drive surface. This allows for torque application, and can reduce the chances of the screw loosing from vibration or stress. There are several head types available, including hex head, socket head, and button head, each designed for a specific type of tool.
Other features of Cap screws include a shoulder, or unthreaded portion, that extends below the head, and a threaded length that is typically longer than the head. They may also be manufactured with a countersunk or flush-head option, which is suitable for applications where the screw protrudes from the surface.
Cap screws are made using a variety of production processes, which can vary depending on the material and design requirements. They can be cold formed, cut or rolled to form the threads, and then subjected to heat treatment or other processing to improve their tensile strength or other properties.