angle grinder vs quern

angle grinder

noun
  • A usually hand-held grinder which uses a pair of internal gears to place the rotational axis of the grinding or cutting wheel perpendicular to that of the driving motor. 

quern

noun
  • A mill for grinding corn, especially a hand-mill made of two circular stones. 

verb
  • To grind; to use a quern. 

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