Wrench

A Wrench is a tool used to turn bolts, nuts or other hard-to-turn items. A Spanner, historically, is a specialized wrench with a series of pins or tabs around the circumference. These pins or tabs fit into the holes or notches cut into the object to be turned. In general usage, the terms wrench and spanner are often used interchangeably—with the English generally preferring spanner.

Double Handled Wrench

Wrenches are generally one of two types: the double–handled wrench (see image at right) and the end wrench; with the end wrench, by far, the most common. Hinged tools, such as pliers or tongs, are not generally considered wrenches.

General Wrenches

• Open-end wrench: a one-piece wrench with a U-shaped opening that grips two opposite faces of the bolt or nut. This wrench is often double ended, with two sizes of openings.
• Box-end wrench (Ring spanner): a one-piece wrench that grips the faces of the bolt or nut with a enclosed opening. The recess is generally a six–point or twelve–point opening. The six–point is used for nuts or bolt heads with a hexagonal shape. The twelve–point can be used with either square or hex shaped nuts and bolt heads but is not a durable. It is also often double–ended.
• Combination wrench: a double-ended tool with an open–end recess on one end and a box–end opening on the other. Both ends generally fit the same size bolt.
• Flare–nut wrench (Tube wrench): used for gripping the nuts on the ends of tubes. The design is similar to a box–end wrench but with an opening to allow the wrench to fit over the tube.
• Adjustable end wrench: an open-ended wrench with adjustable (usually smooth) jaws, also sometimes called by the original patent holder's brand name as a Crescent® Wrench (Crescent Tool and Horseshoe Company).

• Monkey wrench: the original adjustable end wrench with a straight handle and smooth jaws.
• Crescent® wrench: the brand name of an improved version of the adjustable end wrench (see the photo at right) developed by the Crescent Tool and Horseshoe Company. Often, incorrectly, used as a generic term.
• Pipe wrench: an adjustable end wrench with self-tightening properties and hard serrated jaws that securely grip soft iron pipe and pipe fittings. Sometimes known by the original patent holder's brand name as a Stillson® Wrench.

• Socket wrench: a hollow cylinder that fits over one end of a nut or bolt head—may include a handle but usually used with various drive tools. It generally has either a six–point or twelve–point recess, may be shallow or deep, and may have a built-in universal joint. The drive handles generally used are: a break–over (or hinged) handle; a rachet handle (contains a mechanism which allows the socket to be turned without removing it from the nut or bolt); a speed handle (sometimes called a crank handle), or; a screwdriver handle (for use of the socket as a nutdriver). Sockets are often sold as a set containing a collection of sockets of various sizes and associated drive tools; usually including, as a minimum, extensions, a ratchet driver, and a universal joint. Sockets are also used with various power tools.

Specialized Wrenches

NOTE: This image should probably be moved to the Pliers page.

• Spoke wrench: a T-handle wrench with a clearance slot for a wire wheel spoke such as a bicycle wheel and a drive head for the adjustment nut.
• Hex key wrench: a (usually) L-shaped wrench fabricated from hexagonal wire stock of various sizes, used to turn screw or bolt heads designed with a hexagonal recess to receive this wrench. Commonly known also by the brand name Allen Wrench®. This could be more considered a screwdriver than a wrench.
• Strap or Chain wrench: a self-tightening metal or leather strap or a chain attached to a handle, used to grip and turn smooth cylindrical objects.
• Oil-filter wrench: a type of wrench for removing cylindrical oil filters. It may be ether a strap–type wrench or a socket.
• Sink wrench: a self-tightening wrench mounted at the end of a torque tube with a transverse handle at the opposite end. Used to tighten tubing connections to washstand valves in ceramic sinks. The self tightening head may be flipped over to loosen connections.
• Torque wrench: a socket wrench drive tool that measures the amount of twist applied to the socket - this may be indicated visually with a rod or dial or may simply slip when a set torque is exceeded
• Golf shoe spike wrench: a T-handle wrench with two pins and clearance for the spike - allows removal and insertion of spikes in shoes.
• Head nut wrench: a flat wrench with a circular hole and two inward protruding pins to engage slots in the nut. This type of nut is used on bycycles to secure the front fork pivot to the headpiece of the frame.