"one who shapes by means of a swage," 1881, agent noun from swage (v.). In Middle English it was the name of a tool used to make decorative grooves or borders (early 15c.).
Entries linking to swager
swage v.
"to shape or bend by use of a tool," 1831, from swage (n.), also swedge, "tool or die for bending cold metal" (1812), from French suage, according to Century Dictionary from suer "to sweat." Uncertain connection to swage "ornamental moulding" (late 14c.), from Old French souage (Modern French suage), which, according to Klein, is from soue "rope," from Vulgar Latin *soca, probably of Gaulish origin (compare Breton sug "cord"). Swage-block is attested by 1843.