Spanner in the works

Posted by David FG July 01, 2009 at 19:07In reply to Spanner in the works posted by Giles Wynne on July 01, 2009 at 07:29:

"Spanner in the works". Could this have been an expression used to slow down the production line on a car plant, which was going too fast?

I am certainly no engineer, but I would imagine that throwing something like a spanner into a machine would have rather more serious consequences than slowing it up.

DFG