grind away

Randel would grind away at his assignment for the next 12 years.

One of my great regrets is that circumstances compel me to grind away at ephemeral work which is wholly averse to my tastes.

I ought to stop in my corner, grind away at law, and never look to be anything but a boorish country magistrate.

He continued to grind away at the film, and soon had sufficient pictures.

He continued to grind away, getting the proof of the fellow's criminality on the sensitive film.

If I don't stay and grind away at the mill, there is no one to pay for this long journey.