The Collaborative International Dictionary of English v.0.48:

Poppet \Pop"pet\, n.
   1. See Puppet.
      [1913 Webster]

   2. (Naut.) One of certain upright timbers on the bilge ways,
      used to support a vessel in launching. --Totten.
      [1913 Webster]

   3. (Mach.) An upright support or guide fastened at the bottom
      only.
      [1913 Webster]

   4. same as poppit.
      [PJC]

   Poppet head, Puppet head. See Headstock
      (a) .
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Headstock \Head"stock`\ (-st[o^]k`), n. (Mach.)
   A part (usually separate from the bed or frame) for
   supporting some of the principal working parts of a machine;
   as:
   (a) The part of a lathe that holds the revolving spindle and
       its attachments; -- also called poppet head, the
       opposite corresponding part being called a tailstock.
   (b) The part of a planing machine that supports the cutter,
       etc.
       [1913 Webster]