Swaging (/ˈ s w eɪ dʒ ɪ ŋ / ) is a forging process in which the dimensions of an item are altered using dies into which the item is forced. Swaging is usually a cold working process, but also may be hot worked.
The term "swage" comes from the Old French term souage , meaning "decorative groove" or "ornamental moulding". Swages were originally tools used by blacksmiths to form metal into various shapes too intricate to make with a hammer alone. These have handles for holding or pegs for attaching to an anvil, and often a flat head for striking with a hammer. Swage blocks are anvil-like dies with various shapes forged into them, which are also used for forming metal. Swages called "fullers" are specific to making grooves in swords and knives.
Swage is most often pronounced /ˈ s w eɪ dʒ / (AHD format: swāj). Another (less common) pronunciation sometimes heard in the metalworking industries is /ˈ s w ɛ dʒ / (AHD format: swĕj) (perhaps influenced by sledge as in sledgehammer).