 A set of chrome- vanadium metric wrenches, open at one end, box/ring at the other. A wrench or spanner is a tool used to provide grip and mechanical advantage in applying torque to turn objects—usually rotary fasteners, such as nuts and bolts—or keep them from turning. In American English, wrench is the standard term, while spanner refers to 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.) The most common shapes are called open-end wrench and box-end wrench. In British English, spanner is the standard term. The most common shapes are called open-ended spanner and ring spanner. The term wrench refers to a type of adjustable spanner.[1] Higher quality wrenches are typically made from chromium-vanadium alloy tool steels and are often drop-forged. They are frequently chrome-plated to resist corrosion. Hinged tools, such as pliers or tongs, are not generally considered wrenches. [edit] Common wrenches / spanners  Double open-end wrench/spanner - Open-end wrench or open-ended spanner: 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 a different-sized opening at each end. The ends are generally oriented at an angle of around 15 degrees to the longitudinal axis of the handle. This allows a greater range of movement in enclosed spaces by flipping the wrench over.
 Ring spanner/box-end wrench (double-ended offset example) - Box-end wrench or ring spanner: a one-piece wrench with an enclosed opening that grips the faces of the bolt or nut. The recess is generally a six-point or twelve-point opening for use with nuts or bolt heads with a hexagonal shape. The twelve-point fits onto the fastening at twice as many angles, an advantage where swing is limited. Eight-point wrenches are also made for square-shaped nuts and bolt heads. Ring spanners are often double-ended and usually with offset handles to improve access to the nut or bolt (as illustrated).
- Ratcheting box wrench: Is a type of ring spanner, or box wrench, whose end section ratchets. Ratcheting can be reversed by flipping over the wrench, or by activating a reversing lever on the wrench. This type of wrench combines compact design of a box wrench, with the utility and quickness of use of a ratchet wrench. A variety of ratcheting mechanisms are used, from simple pawls to more complex captured rollers, with the latter being more compact, smoother, but also more expensive to manufacture.
 Combination spanner/wrench - Combination wrench or combination spanner: a double-ended tool with one end being like an open-end wrench or open-ended spanner, and the other end being like a box-end wrench or ring spanner. Both ends generally fit the same size of bolt.
- Flare-nut wrench, tube wrench or line wrench: used for gripping the nuts on the ends of tubes. It is similar to a box-end wrench but, instead of encircling the nut completely, it has a narrow opening just wide enough to allow the wrench to fit over the tube. This allows for maximum contact on plumbing nuts, which are typically softer metals and therefore more prone to damage from open-ended wrenches.
 Adjustable wrench/spanner - Adjustable wrench, adjustable spanner or shifting spanner: a type of wrench with a movable jaw that adapts the tool to different sized objects.
- Monkey wrench or gas grips: an old type of adjustable end wrench with a straight handle and smooth jaws that whose gripping faces are perpendicular to the handle.
- Adjustable end wrench: the most common type of adjustable wrench in use today. The adjustable end wrench differs from the monkey wrench in that the gripping faces of the jaws are displaced to a (typically) 15 degree angle relative to the tool's handle, a design feature that facilitates the wrench's use in close quarters. The modern adjustable end wrench was first developed by Johansson (with Bahco)[2] or by the Crescent Tool and Horseshoe Company, and is often referred to as a "Crescent wrench", regardless of the actual manufacturer.
- Pipe wrench: a tool that is similar in design and appearance to a monkey wrench, but with self-tightening properties and harden 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, universal joint and sockets - Socket wrench: a hollow cylinder that fits over one end of a nut or bolt head. It may include a handle, but is usually used with various drive tools. It generally has a six-point, eight-point or twelve-point recess, may be shallow or deep, and may have a built-in universal joint. The drive handles generally used with sockets are:
- Break-over (or hinged) handle: Also known as a jointed nut spinner, flex head nut spinner or breaker bar, this tool is a long non-ratcheting bar that allows the user to impart considerable torque to fasteners, especially in cases where corrosion has resulted in a difficult-to-loosen part.
- Ratchet handle: contains a one-way mechanism which allows the socket to be turned without removing it from the nut or bolt simply by cycling the handle backward and forward.
- Speed handle, crank handle or speed brace
- Screwdriver handle: for use of the socket as a nutdriver.
- Torque wrench: a socket wrench drive tool that is employed to impart a precise amount of torque to a fastener, essential in many cases during the assembly of precision mechanisms.
- Crowfoot wrench: a type of socket designed to fit some of the same drive handles as the regular socket but non-cylindrical in shape. The ends are the same as those found on the open-end, box-end, or the flare-nut wrenches. These sockets use for use where space restrictions preclude the use of a regular socket. Their principal use is with torque wrenches.
- Saltus wrench: similar in concept to a socket wrench. A Saltus wrench features a socket permanently affixed to a handle. Sockets are not interchangeable as with a socket wrench. The socket often rotates around the handle to allow the user to access a fastener from a variety of angles. Commonly a Saltus wrench is part of a double-ended wrench, with an open-end type head on the opposite side from the socket head.
- Box spanner: a tube with six-sided sockets on both ends. It is turned with a short length of rod (tommy bar or T bar) inserted through two holes in the middle of the tube.
- Striking face box wrench: also referred to as a slogging/flogging spanner, this is a specialized wrench with a block end to the handle specifically designed for use with a hammer, enabling one to impart great force to release large nuts and bolts where the shock of the impact is useful in breaking rust or paint.
[edit] Other general wrenches / spanners - Wrenches for screws and bolts with internal sockets are generally referred to in the UK as keys, and include:
- Allen wrench, Hex key or Allen key: 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 the wrench.
- Bristol wrench or Bristol spline wrench: another wrench designed for internal socket-head screws and bolts. The cross-section resembles a square-toothed gear. Not a common design, it is chiefly used on small set screws.
- Torx wrench: an internal socket-head screw design. The cross-section resembles a star. Commonly used in automobiles, automated equipment, and computer components as it is resistant to wrench cam-out and so suitable for use in the types of powered tools used in production-line assembly.
- Strap wrench or chain wrench: a self-tightening wrench with either a chain or strap of metal, leather, or rubber attached to a handle, used to grip and turn smooth cylindrical objects (such as automotive oil filters). In bicycle repair circles it is known as a chain whip and is used primarily to remove and install cassettes on rear hubs.
 Schematic showing how an alligator wrench allows the user to grip square-headed fasteners of various sizes - Alligator wrench: a formerly common type of wrench that was popular with mechanics, factory workers, and farmers for maintenance, repair and operations tasks in the days when fasteners often had square rather than hex heads. The wrench's shape suggests the open mouth of an alligator.
[edit] Specialized wrenches / spanners  Double handled tap wrench - Cone wrench: A special thin wrench required to adjust the bearing cones on a hub. Most front hubs use a 13 mm, most rears use 15 mm.
- Spoke wrench or spoke key: a wrench with a clearance slot for a wire wheel spoke such as a bicycle wheel and a drive head for the adjustment nipple nut.
- Tap wrench: a double-handled wrench for turning the square drive on taps used in threading operations (cutting the female threads such as within a nut) or a precision reamer.
- Die wrench: A double-handled wrench for turning the dies used in threading operations (cutting the male threads such as on a bolt).
- Drum wrench: also called "bung wrench." A tool commonly used to open bungs on large 55-gallon drums.
- Lug wrench: a socket wrench used to turn lug nuts on automobile wheels. Commonly known in the UK as a wheel brace.
- Plumber wrench: a tool to screw (rotate with force) various pipes during plumbing.
- Tuning wrench: a socket wrench used to tune some stringed musical instruments.
- Strap wrench: a rigid handle connected to a flexible, non-marring high friction strap. The strap is looped around the item then affixed to the handle. Used on round and odd shaped objects.
- Oil-filter wrench: a type of wrench for removing cylindrical oil filters. It may be either 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 nuts are often located deep in recesses. The self-tightening head may be flipped over to loosen connections. Also known as a Basin wrench.
- Podging wrench or Podger: A steel erecting tool which consists of a normal wrench at one end and a spike at the other, used for lining up bolt holes (typically when mating two pipe flanges. In the U.S. often called a spud wrench.
- 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 bicycles to secure the front fork pivot bearing to the headpiece of the frame.
- Fire hydrant wrench (hose connection): The hose connection has a threaded collar with a protruding pin. From the handle of the wrench an arc has at its end a loop to engage the pin.
- Fire hydrant wrench (valve operator): This is a pentagonal (five-sided) box wrench. Avoiding a hex shape for the lug makes the valve tamper-resistant: with the opposite faces nonparallel, unauthorized opening of the hydrant is less likely, because the would-be opener lacks a suitable tool.
- Chain wrench: Similar to a pipe wrench, but uses a chain similar to a drive chain, instead of an adjustable jaw. The links of the chain have extended pegs which fit into grooves in the front of the handle, with one end of the chain attached permently to the handle. This is used in situations where pipe wrenches can't maintain a proper grip on an object such as a wet or oily pipe. Larger versions of chain wrenches are sometimes known as "bull tongs" and are used with large diameter pipe such as is used deep wells.
- Power wrench: A broad type of wrenches that use electricity or compressed air to power the wrench.
- Impact wrench: A compressed air (pneumatic) powered wrench commonly used in car garages and workshops to tighten and remove wheel nuts.
- Graduated wrench: An adjustable wrench with a small number (usually 2–4) of discrete sizes. This is sometimes used as an inexpensive substitute for a monkey wrench.
- Wing nut wrench: A tool specifically for use with wing nuts, allowing the application of greater torque than is possible by hand. It is not generally advised to use such spanners as the primary purpose of wing nuts is to prevent them from being tightened more than "hand tight".[citation needed]
- Mole wrench: is not a wrench but self-locking pliers.
- Rigger-Jigger: A spanner used in attaching riggers to rowing boats with offset to allow users fingers to keep grip when flush with boat. 10mm at one end, 13mm at the other.
- Tappet wrench: A spanner of small to moderate size constructed similarly to an open ended wrench, but with a thinner cross section. Its purpose is to apply torque to the fasteners found on the valve trains of older engines, especially automobile engines, where the valve train required adjustment of the tappets (also known as lifters). Tappets, push rods, rocker arms and similar adjustable pieces are often equipped with locknuts which are thinner than standard nuts, due to space limitations. Frequently, the hex section of the adjustment is contiguous to the lock nut, thus requiring a thinner "tappet wrench" to be used.
[edit] History Wrenches have existed for many centuries, but saw a great blossoming of development starting in the nineteenth century. The first patent for a wrench was granted in 1835 to Solymon Merrick.[3] [edit] References [edit] External links |
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