spanner

crescent spanner

An open-end adjustable spanner with a worm-drive thumbwheel. When the term adjustable spanner or adjustable wrench is used, this type (branded with any of many brands) is usually the type meant.

spanner in the works

Something that disrupts smooth operation or functioning.

throw a spanner in the works

To introduce a problem, dilemma or obstacle, something unexpected or troublesome.