swage
A tool, used by blacksmiths and other metalworkers, for shaping of a metal item.
"I made a swage and hammered out the test bars to the required .615 inch plus or minus .003, the thickness of a sheet of paper. […]
Where it comes from
Inherited from Middle English swage, from Middle French souage, from Old French souage (“decorative groove”), from soue (“rope”), from Vulgar Latin *soca, from Gaulish *souca (“cord”), from Proto-Celtic *soukā, from Proto-Indo-European *sew- (“to twist, bend”).
Adapted from the Wiktionary entry swage (CC BY-SA 4.0).