bang (away) at
1. To strike something repeatedly. Quit banging away at the door, I'm coming! I banged away at that nail and still can't get it to go into the wall.
2. To mention or reference something repeatedly. That film really bangs away at the idea of social justice.
3. To work steadily on a project or assignment. I'm banging away at this report so that I can finish it tonight.
bang (away) at something
to hit at something repeatedly, causing harm or making noise. Someone is banging away at the door. Stop banging at the door.