The Collaborative International Dictionary of English v.0.48:

Shingling \Shin"gling\, n.
   1. The act of covering with shingles; shingles, collectively;
      a covering made of shingles.
      [1913 Webster]

   2. (Metal) The process of expelling scoriae and other
      impurities by hammering and squeezing, in the production
      of wrought iron.
      [1913 Webster]

   Shingling hammer, a ponderous hammer moved by machinery,
      used in shingling puddled iron.

   Shingling mill, a mill or forge where puddled iron is
      shingled.
      [1913 Webster]