Dictionary

work like a nailer en · VERB

(dated, qualifier:simile) To work very hard.
- Lee had to work like a nailer to get the awkward craft turned about, and then by great labor at the crank "for the space of five glasses by the ships' bells, or two and a half hours," at last he arrived under the stern of what he felt certain was the Eagle. 1947 January 13, Stewart H. Holnrook, “Lost Men of American History”, in Life, volume 22, number 2, New York, page 84:
- Boyce was working away like a nailer at His Grace's colt, an exertion he might have spared himself , but that it is necessary to do something for one's money 1834 September, Craven, "Goodwood Races – Tuesday, July 29", The Sporting Magazine (London) s. 2, vol. 9, no. 53, p. 388
- You might as well understand in the beginning that he'll have to work like a nailer for a good many years before he gets anywhere in the diplomatic service 1918, George Barr McCutcheon, The City of Masks, New York: Dodd, Mead, page 191:

Spelling	Features	Source
working like a nailer	Tense=Pres, VerbForm=Part	lexicographic
worked like a nailer	Tense=Past, VerbForm=Part	lexicographic
worked like a nailer	Tense=Past	lexicographic
works like a nailer	Number=Sing, Person=3, Tense=Pres	lexicographic