to have private reasons for being involved in sth or for arguing for a particular cause :
She had no axe to grind and was only acting out of concern for their safety.
to have private reasons for being involved in sth or for arguing for a particular cause :
She had no axe to grind and was only acting out of concern for their safety.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005