knurl vs slub

knurl

noun
  • A contorted knot in wood. 

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

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

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

slub

noun
  • A small thickened portion or knot found on linen yarn, caused by defects. 

  • Fabric fiber produced by slubbing. 

verb
  • To draw and twist fibers in order to prepare them for spinning. 

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