bitstock vs capstan

bitstock

noun
  • A hand tool consisting of a crank which holds a fitted rotating drill bit tip, designed to bore holes in rigid materials, by cutting a disc in a spiral fashion. 

capstan

noun
  • A vertical cylindrical machine that revolves on a spindle, used to apply force to ropes, cables, etc. It is typically surmounted by a drumhead with sockets for levers used to turn it. 

  • A rotating spindle used to move recording tape through the mechanism of a tape recorder. 

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