Key Steel - Imperial
Key Steel, or Key bar as it is sometimes called, is an unalloyed length of medium steel bar. It is available in 304mm (1 foot) lengths.
Key Steel comes in both square and rectangular section options. It is most commonly used to lock a component such as a sprocket or gear into a keyway on a shaft.
Imperial is a generic term used to describe threads that were in common use before the metric standard was adopted. Types of imperial threads include UNC, UNF, BSW, BSF, BA etc. Many of these thread types are still commonly used today.