IdiomCenter.com

work one's fingers to the bone/ work one's tail off / work one's butt off (exert oneself, work very hard) — работать на износ; работать на покладая рук; работать, не щадя себя; работать как проклятый; как ломовая лошадь

Example 1: He' s working his fingers to the bone to support his family

Example 2: I work my tail off and then the government takes half my income in taxes.

see also
[burn the candle at both ends]
[работать сутками]
[burn the midnight oil]