tinker Idiom
Not worth a tinker's dam
This means that something is worthless and dates back to when someone would travel around the countryside repairing things such as a kitchen pot with a hole in it. He was called a 'tinker'. His dam was used to stop the flow of soldering material being used to close the hole. Of course his 'trade' is passé, thus his dam is worth nothing.
worth a tinker's dam|dam|tinker's dam|worth
adj. phr.,
informal Not worth anything; valueless.
As a bricklayer he was not worth a tinker's damn. I am not familiar with the subject so my opinion would not be worth a tinker's dam.
tinker
tinker In addition to the idiom beginning with
tinker, also see
not worth a damn.
tinker with
tinker with Try to repair, work aimlessly or unskillfully with, as in
He tinkered with the engine all day but it still wouldn't start. This idiom, first recorded in 1658, alludes to working as a tinker, that is, mending metal utensils.