Swage

From Old French souage.

Full definition of swage

(plural swages)

A tool, used by blacksmiths and other metalworkers, for cold shaping of a metal item.

2003, Gene Logsdon, The Pond Lovers, University of Georgia Press (2003), ISBN 0820324698, page 45:"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.
2005, Mike McCarthy, Ships' Fastenings: From Sewn Boat to Steamship, Texas A&M University Press (2005), ISBN 9781585444519, page 87:If he were making round or square-sectioned nails, the blacksmith also kept a "swage" near the anvil. If different sizes, shapes, and heads were required, the nailor had a a number of swages or a number of holes in the one swage.
2008, Wilbur Cross, Gullah Culture in America, Praeger (2008), ISBN 9780275994501, page 73:The blacksmith let me help out, hold the horse while he was putting the shoe on, turn the hand forge, clean up the shop. And after awhile he taught me names of everything. He'd say, 'Boy, hand me the three-inch swage,' and I had to know just what he wanted. I learned that way."

A swage may be variously shaped or grooved on the end or face, but typically involves working with cold metal by forcing it into a die.

From assuage by aphesis.