Good workmanship depends no more on the quality of the tools than it does on the way in which they are used, so to blame the tools for the bad workmanship is to attempt to excuse one’s own lack of skill.
For example: ‘I lost the watch because my racket needed re-stringing.’ ‘my essay wasn’t very good because I had to use someone else’s pen.’ ‘How did you expect me to me to catch fish with this rod?’ To all these the response could be: ‘A bad workman always blames his tools.’
Other cultures have similar proverbs: In Poland they say, a bad dancer blames the hem of her skirt; In Netherlands they says, a drowning man blames the water because he cannot swim; In Indonesia they says, the ugly person blames the mirror. But they all mean the same thing. They expose the heart of those who refuse to take personal responsibility and find excuses to cover up their failure.
The origin of this proverb is very old. It is first cited in French from the 13th century in the form of “a bad workman can never find a good tool”. Often the specific tradesman is mentioned, e.g. blacksmith, carpenter, etc. Whatever the profession, if bad or incompetent, they all blamed their tools.