Socket Screw, also known as Allen head screws, are used in a variety of applications, particularly where space is tight or access is restricted. These fasteners are extremely strong (link to tensile strength and torque specification chart), inexpensive and easy to install using a socket wrench or Allen hex key. They are commonly found in industrial machinery, steel fabrication and assembly lines.
Socket screws have a cylindrical head with a recessed hexagonal drive hole. They can be positioned over threaded holes in materials like metal, wood, plastic and other non-metals, and then tightened by inserting the allen wrench or hex key into the socket drive recess and turning clockwise. When tightened, they are secure and provide better tensile strength than other types of screw or bolt.
There are several different types of socket cap screws, such as flat head and button. They all feature a hex socket drive hole, but have different head styles to fit in tight spaces. Flat head socket caps are countersunk, and only expose a small portion of the head above the mating surface. Button heads have a mushroom-like shape that fits into the head of the screw, creating a snug fit without taking up too much space.
Socket shoulder screws have both tensile and shear strengths, and they are ideal for use in pre-tapped holes that need alignment with some tolerance. They are also commonly used in machinery, power transmission and hand and power tools, such as tooling, metal stamping dies and plastic injection molds. Socket Screw