The Collaborative International Dictionary of English v.0.48:

Soleplate \Sole"plate`\, n. (Mach.)
   (a) A bedplate; as, the soleplate of a steam engine.
   (b) The plate forming the back of a waterwheel bucket.
       [1913 Webster] Soler

The Collaborative International Dictionary of English v.0.48:

Bedpiece \Bed"piece`\, Bedplate \Bed"plate`\, n. (Mach.)
   The foundation framing or piece, by which the other parts are
   supported and held in place; the bed; -- called also
   baseplate and soleplate.
   [1913 Webster]