keep one's shoulder to the wheel vs keep one's nose to the grindstone

keep one's shoulder to the wheel and keep one's nose to the grindstone both are verbs.

Word	Noun	Adjective	Verb	Adverb
keep one's shoulder to the wheel	No	No	Yes	No
keep one's nose to the grindstone	No	No	Yes	No

As verbs, keep one's shoulder to the wheel and keep one's nose to the grindstone are synonyms defined as:

keep one's shoulder to the wheel and keep one's nose to the grindstone: work doggedly or persistently

Other synonyms of keep one's shoulder to the wheel include peg away, plug away, slog.

keep one's shoulder to the wheel (verb)	keep one's nose to the grindstone (verb)
work doggedly or persistently	work doggedly or persistently