semicircular gouging chisel
• (n.) A tool with a semicircular edge, -- used by engravers to clear away the spaces between the lines of an engraving.
Scaup'er noun [ Confer Scalper .] A tool with a semicircular edge, -- used by engravers to clear away the spaces between the lines of an engraving. Fairholt. 
scorper noun a graver used to scoop out broad areas when engraving wood or metal