The Collaborative International Dictionary of English v.0.48:

Crampet \Cram"pet\ (kr?m"p?t), n. [See Cramp,n.]
   1. (Mil.) A cramp iron or cramp ring; a chape, as of a
      scabbard. [Written also crampit and crampette.]
      [1913 Webster]

   2. One of the plates of iron, with attached spikes, forming a
      pair of crampoons; hence (Curling), an iron plate for a
      player to stand on when delivering the stones.
      [Webster 1913 Suppl.]