A type of bolt with a recess inside the bolt's head. Socket head cap screws require assembly with a hex key (Allen Key) or a hex bit driven by an impact tool. Hex socket (Allen) drives are compact and easy to drive, but prone to cam-out.
The most common types of Socket Cap Screws are:
- Socket head cap screw - long cylindrical heads
- Flat heads - countersunk (cone shaped under the head) with a flat top.
- Button heads are rounded and low profile
A set screw is a type of screw used to secure an object within or against another object. Pulley's, gears, and shafts are the most common uses for set screws. Set screws are usually headless, (no head projecting beyond the major diameter of the screw thread, and fully threaded. The set screw passes through a threaded hole in the outer object and is tightened against the inner object to prevent it from moving relative to the outer object. It exerts a clamping force through the bottom tip that projects through the hole. Set screws can have a variety of tips, including but not limited to - cup point, knurled point, cone point and dog point.
ASTM A574 - Standard Specification for Alloy Steel Socket-Head Cap Screws
ANSI B18.3 - Socket Head Cap Screw
ASTM F912 - Standard Specification for Alloy Steel Socket Set Screws
ASME B1.13M - Metric Screw Threads
DIN912 - 12.9 Hexagon Socket Head Cap Screws
DIN 916 - Socket Set Screws Cup Point