unbolt vs unpin

unbolt

verb
  • To unlock by undoing the bolts of. 

unpin

verb
  • To unfasten by removing a pin. 

  • To get (a piece) out of a pin. 

  • To detach (an icon, application, etc.) from the place where it was previously pinned. 

  • To undo the pinning or fixing of (an array in memory, a security certificate, etc.) so that it can be modified again. 

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