ax to grind vs resentment

ax to grind

noun
  • A grudge or grievance, with implications of confrontation. 

  • A proposition or point of view to advocate, especially motivated by self-interest. 

resentment

noun
  • Anger or displeasure stemming from belief that one has been wronged or betrayed by others; indignation. 

How often have the words ax to grind and resentment occurred in a corpus of books? (source: Google Ngram Viewer )