braze vs stiffen

braze

verb
  • To cover with brass, or as with brass. 

  • To join two metal pieces, without melting them, using heat and diffusion of a jointing alloy of capillary thickness. 

noun
  • A kind of small charcoal used for roasting ore. 

stiffen

verb
  • To make stiff. 

  • To become stiff. 

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