gallet vs knurl

gallet

verb
  • To use this masonry technique. 

noun
  • A splinter of stone inserted into the wet mortar of masonry. 

knurl

verb
  • To roll or press a pattern of ridges or indentations into a part for grip. 

noun
  • A crossgrained protuberance; a nodule; a boss or projection. 

  • A contorted knot in wood. 

  • A lined or crossgrained pattern of ridges or indentations rolled or pressed into a part for grip. 

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