Whenever Charles Miner suspected an ulterior motive, he would say quietly ‘That man has an axe to grind!’
When someone has a hidden, ulterior motive for what he does, we say ‘he has an axe to grind’. The origin of this saying appears to be an essay in the Luzerne Federalist, a Pennsylvania newspaper, for September 7th, 1810. The author, Charles Miner, edited the paper with his brother Asher; later, Charles became an anti-slavery campaigner and a Congressman.