trundlehead

from The Collaborative International Dictionary of English v.0.48
Trundlehead \Trun"dle*head`\, n.
   1. (Gearing) One of the disks forming the ends of a lantern
      wheel or pinion.
      [1913 Webster]

   2. The drumhead of a capstan; especially, the drumhead of the
      lower of two capstans on the sane axis.
      [1913 Webster]
    

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