List of screw and bolt types

This is a list of types of threaded fasteners, including both screws and bolts.

Lag bolts are usually used with an expanding insert called a lag in masonry or concrete walls, the lag manufactured with a hard metal jacket that bites into the sides of the drilled hole, and the inner metal in the lag being a softer alloy of lead, or zinc alloyed with soft iron.

The coarse thread of a lag bolt and lag mesh deform slightly, making a secure, near watertight, anti-corroding, mechanically strong fastening.

A hex key (sometimes referred to as an Allen wrench, Allen key, or hex driver) is required to tighten or loosen a socket screw.

Socket head capscrews are commonly used in assemblies that do not provide sufficient clearance for a conventional wrench or socket.