plowshare vs trowel

plowshare

noun
  • The cutting edge of a plow, typically a metal blade. 

trowel

noun
  • A gardener’s tool, shaped like a scoop, used in taking up plants, stirring soil etc. 

  • A mason’s tool, used in spreading and dressing mortar, and breaking bricks to shape them. 

  • A tool used for smoothing a mold. 

verb
  • To apply (a substance) with a trowel. 

  • To pass over with a trowel. 

  • To apply something heavily or unsubtly. 

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