wrench in the works

wrench in the works (plural wrenches in the works)

1. (US) Synonym of spanner in the works.
   • 1989, Aleksandr Solzhenitsyn, translated by H. T. Willetts, August 1914, Farrar, Straus and Giroux, →ISBN, page 72:

     Such a big staff, with ludicrously little to do, inevitably began interfering with arrangements made by the army commanders. Its actual efforts at coordination were from the start so many wrenches in the works.