pencil sharpener vs sawdust

pencil sharpener

noun
  • A device used to sharpen pencils by shaving the wood at one end. 

sawdust

noun
  • The fine particles (dust) created by sawing wood or other material. 

verb
  • To sprinkle with sawdust. 

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