Hex bolts have a chamfered point to aid insertion into a tapped hole or nut. Length is measured from under the head.
Silicon Bronze is known as a high-strength alloy that stands up well under harsh conditions, with excellent resistance to corrosion caused by brine, gases, and sulphite solutions. It is also nonmagnetic and has good friction reduction qualities and a high degree of thermal conductivity. Fasteners made from Silicon Bronze are frequently used for marine construction and in applications for liquid handling and sewage disposal equipment.
Hex head fasteners can be driven with simple wrenches, and require minimal clearance above the fastener because they can be driven or loosened from the side.
A threaded fastener's size name includes information about the major external diameter, followed by the threads per inch, which indicates if it is coarse or fine.