The Collaborative International Dictionary of English v.0.48:

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.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

set chisel
    n 1: narrow chisel made of steel; used to cut stone or bricks
         [syn: cold chisel, set chisel]