A socket head cap screw features a cylindrical head and a hexagonal recess. This specialised drive requires a hex wrench or Allen key to tighten or loosen the screw. Hex socket cap screws have threads along their length and can either be fully or partially threaded, depending on the application. In this guide, we'll take a closer look at these screws, covering:
Advantages of socket head cap screws
Types of socket head cap screws
Socket head cap screw dimensions
How to measure socket head screws
Advantages of socket head cap screws
Socket screws are the preferred screw when bolts and nuts can't be used. The hex socket (Allen) screw drive gives the screw six stress-bearing sides for use with an Allen wrench (hex key). This enables the screw to resist cam-out better than most other drives.
Compared to other screws, hex socket screw types of the same size enable you to achieve higher torque and clamping force. This, in turn, allows you to use fewer socket head screws than you'd have to install otherwise. Fewer pieces of hardware reduce the weight of your finished application. Fewer screws also reduce your costs and the time needed to drill holes and tap into surfaces.
Socket head cap screws are also known by different names such as Allen head screws, Allen drive screws, hex socket screws, hex cap screw, hex socket head cap screw, hex socket head screw and hex socket head cap screws.
Many people in the trades simply call it a socket screw, but be aware that this is also the name for a different screw type used for light sockets. Whichever name you use, socket head screw types are preferred when bolts and nuts can't be used. The cylindrical head style of the socket head screw has a low profile compared to other fasteners, making it ideal for use in tight spaces.
Types of socket head cap screws
There are several socket head types to choose from. Hex socket screw materials are available in plastic and metal.