Source : Webster's Revised Unabridged Dictionary (1913)

Set chisel \Set chisel\ (Mech.)
   A kind of chisel or punch, variously shaped, with a broad
   flat end, used for stripping off rivet heads, etc.

Source : WordNet®

set chisel
     n : narrow chisel made of steel; used to cut stone or bricks
         [syn: {cold chisel}]