hammer beam vs spar

hammer beam

noun
  • A member of a kind of roof truss (a hammer-beam truss), so framed as not to have a tiebeam at the top of the wall. Each principal has two hammer beams, which occupy the situation, and to some extent serve the purpose, of a tiebeam. 

spar

noun
  • A beam-like structural member that supports ribs in an aircraft wing or other airfoil. 

  • Any crystal with readily discernible faces. 

  • A rafter of a roof. 

  • A thick pole or piece of wood. 

  • A sparring session; a preliminary fight, as in boxing or cock-fighting. 

  • Any of various microcrystalline minerals, of light, translucent, or transparent appearance, which are easily cleft. 

  • Any linear object used as a mast, sprit, yard, boom, pole or gaff. 

verb
  • To contest in words; to wrangle. 

  • To supply or equip (a vessel) with spars. 

  • To fight, especially as practice for martial arts or hand-to-hand combat. 

  • To strike with the feet or spurs, as cocks do. 

How often have the words hammer beam and spar occurred in a corpus of books? (source: Google Ngram Viewer )