monkey wrench

And you know what could really throw a monkey wrench into the whole effort?

Whenever these dissentions brought matters to a standstill, I would have to get out and apply the monkey-wrench of peace.

If Monkey-wrench screws down hard on me, you'll come to the rescue, won't you, Colonel?

Then Mac thrust his hand in between the two, and gave the Colonel a monkey-wrench grip that made the Kentuckian's eyes water.

"I think that's a crazy-looking monkey-wrench you've got there," observed Annixter, glancing at the instrument in Hooven's hand.

It seemed a good suggestion, and taking the monkey wrench they broke open every locker.