throw a monkey wrench into

throw a monkey wrench in(to) (something)

To disrupt, foil, or cause problems to a plan, activity, or project. Primarily heard in US. We had everything in line for the party, but having the caterer cancel on us at the last minute really threw a monkey wrench into our plans! It'll really throw a monkey wrench in the works if the board decides not to increase our funding for this project.
See also: monkey, throw, wrench

throw a monkey wrench into

Sabotage or frustrate a project or plans, as in The boss threw a monkey wrench into our plans when he said we'd have to work Saturday. This transfer of industrial sabotage-that is, throwing a tool inside machinery-to other subjects dates from the early 1900s.
See also: monkey, throw, wrench
References in periodicals archive ?
will throw a monkey wrench into the media company's announced merger with Tribune Media.
Even though we plan and have good procedures in place, something is going to go out of control and throw a monkey wrench into our efforts.
What we see now is, in addition to a sincere effort, also a bold diplomatic move to derail this headlong rush towards war that exists here in the United States and try to throw a monkey wrench into the machinery of war,'' Mr Ritter told the BBC Radio 4 Today programme.
Earlier this year I vowed that Americans United would throw a monkey wrench into Pat Robertson's political machine," said Lynn.
Bankruptcies, mergers and acquisitions throw a monkey wrench into such plans.
Commented Lynn, "Last year when the Christian Coalition said it would draft 100,000 churches into its political machine, I vowed that Americans United would throw a monkey wrench into those works.
Financial and lending institutions, which occupy about a third of New York's office space, appear to have started to cut back on their space requirements, and that trend, if it gains momentum, could throw a monkey wrench into the Midtown recovery.
There were great expectations that this ancient fellow would throw a monkey wrench into previous notions of the course of early hominid evolution.