Baltimore wrench
n.— «Baltimore wrench. Hammer and flat chisel used to remove tight nuts.» —“Machinists’ Slang and Jargon [‘add machinists’]” by Mendelowitz in Wisc., Ohio, N.Y., Ind., Mich., Ala. Lexicon of Trade Jargon , 1938-39. (source: Double-Tongued Dictionary)