wrench

A wrench, also called a spanner in some regions, is a hand tool designed to apply torque to turning fasteners, such as nuts and bolts. It typically consists of a handle and a jaw or socket that grips the fastener, allowing the user to tighten or loosen it. Wrenches are used in a wide range of mechanical, automotive, plumbing, and industrial applications, and they work by converting the user’s applied force into rotational force on the fastener.

Common types include adjustable wrenches, which have a movable jaw to fit different sizes, open-end wrenches with U-shaped openings, box-end wrenches with enclosed rings that grip the fastener more fully, and combination wrenches that pair an open-end and a box-end on opposite ends. Socket wrenches use interchangeable sockets and a ratcheting mechanism to turn fasteners with repeated motions. Torque wrenches are calibrated to apply a specific torque. Hex keys, or Allen wrenches, are L-shaped tools used for hexagonal socket screws. Pipe wrenches, with serrated jaws and a long handle, are designed for gripping round pipes, while other specialized wrenches exist for unique fastener shapes.

Materials and construction emphasize strength and durability, often featuring steel alloys that are heat-treated, with finishes such as chrome plating to resist corrosion. Wrenches are produced in metric (millimeters) and SAE (inch) sizes, and they vary in jaw geometry, including 6-point and 12-point designs to fit corresponding fasteners securely.

Usage considerations include selecting the correct size, aligning the wrench with the fastener, applying steady force, and avoiding slipping or using the tool as a lever or striking tool, which can damage the fastener or tool. Proper storage and maintenance help prevent rust and wear. The wrench remains a fundamental tool in many trades due to its versatility and straightforward operation.