BBB Etymology - Axe to Grind

The Oxford English Dictionary says the phrase originated with Ben Franklin, but the OED's first published citation is not from Franklin but from his fellow Pennsylvanian, Charles Miner, a Connecticut-born essayist and newspaper editor. From Essays from the Desk of Poor Robert the Scribe in which Miner recounts the tale of a boy who gets conned into turning the grindstone for someone who wants his ax sharpened.

When I see a merchant over-polite to his customers, begging them to taste a little brandy and throwing half his goods on the counter,—thinks I, that man has an axe to grind.