Types of Wrenches

Wrenches are categorized based on the shape of their ends. The most commonly used types for home use are open-end wrenches and box wrenches. Open-end wrenches are used for common nuts and bolts. Box wrenches have ends designed to turn hex and square bolts. Combination wrenches combine the functions of both open-end and box wrenches. You’re also likely to find adjustable wrenches and socket wrenches in any well-stocked toolbox.

Wrench kits are a convenient way to get an array of organized, commonly used wrench sizes from smallest to largest.

Open-end wrenches are a double-ended wrench with a U-shaped head at each end. They are used for nuts and bolts that are hard to reach. The design allows the user to approach the fastener from two different directions. One head is slightly smaller than the other, allowing you to work on bolts of slightly differing sizes with one tool. These wrenches are sold in both standard wrench sizes and metric.

Box wrenches have closed loops at each end. They are designed to accommodate both hex bolts and square bolts. Box wrenches are usually sold in sets. The better models may feature a slightly offset design. Offset wrenches allow the heads to get a better grip on recessed nuts. Because of their closed-end design, box-ended wrenches are better able to grip fasteners than open-ended wrenches without slipping or stripping the fittings.

Combination wrenches combine the benefits of box wrenches and open-end wrenches. One side is a closed loop for hexagonal or square nuts. The other end is an open U-shape. Used most often for difficult nuts, a combination wrench's closed end loosens the nut so the open end can be used to quickly unscrew it.

The adjustable wrench is one of the most common types of wrenches for household use. Also called a crescent wrench, it has a single open end with a crescent-shaped jaw that opens or closes with the turn of a spiral screw in the head. Because the wrench is adjustable, it can take the place of a set of open-end wrenches, making it a space-saving choice.

Socket wrenches adjust nuts and bolts without repositioning the wrench. They have a drive mechanism similar to a ratcheting wrench. If the wrench meets resistance, reverse the direction and then continue tightening or loosening the fastener. Socket wrenches also have a variety of different-sized heads that you can switch out.

If you work on cars, there are several different wrenches you'll need. Each one is suited to a different aspect of auto repair.

• A lug wrench is used to remove or install a tire’s lug nuts. They are often used on the go to fix a sudden flat tire. The lug wrench is cross-shaped with a socket of a different size at each end.
• An impact wrench looks a lot like a power drill and comes in two styles. Cordless impact wrenches use a rechargeable battery. An air impact wrench operates with an air compressor. This tool is used to remove and attach nuts from tires quickly. An impact wrench is ideal for jobs that require very high torque and power, such as replacing multiple tires.
• A strap wrench has an adjustable loop attached to a sturdy handle. The loop may be made of rubber, chain or metal, depending on the usage. The purpose of a strap wrench is to grip and turn oil filters in automotive repair.
• A spark plug wrench is a double-ended wrench featuring a T-bar handle. It is used to adjust spark plugs in combustion engines such as in cars and lawnmowers. They are often part of an automotive tool kit.
• A fan clutch wrench is a single-end wrench that’s flat with a U-shaped head. These are highly specialized wrenches intended for removing fan clutches from cars, trucks, vans and other vehicles.
• A torque wrench is a version of a socket wrench that has carefully calibrated internal works. They create a specific type of applied force and are most often used for engine repair. Torque wrenches are not meant for loosening fasteners.
• Similar to a box wrench, a flare nut wrench is double-ended. However instead of a fully closed loop, the ends have five sides. One open side allows the wrench to loosen and tighten hex nuts that are used as coupling for a tube.

Strap wrenches can be used in plumbing repair or to open jars. They're good for any task that needs a larger or broader grip point.

There are several wrenches specially designed for working on bikes.

• The dog bone wrench is a double-ended box wrench with a different socket size on each end. The dog bone wrench is designed to fit into tight spaces, making it ideal for the intricate nature of bike repair.
• A spoke wrench is usually a small, disk-shaped wrench with a slotted end that fits around the spoke itself. It has an open end that turns the spoke nut. They’re used to adjust the tension of the spokes.
• The pedal wrench is a dual-sided wrench with a U-shaped indentation in each side. It is used to repair a bike’s pedals.
• A cone wrench is a double-ended, open-end wrench. It’s very thin and flat. It is extremely useful for turning bolts or fittings with little to no clearance. Cone wrenches can also be used to adjust leveling nuts on large appliances such as washers or refrigerators.

Plumbing requires different types of wrenches for different fixtures.

• A pipe wrench is used for turning metal pipes and fittings. It has an open end with an adjustable jaw that fits pipes of various diameters, saving space in your toolbox.
• A basin wrench has a long, thin handle affixed to a pair of asymmetrical jaws joined by a pin. The wrench is designed to reach fittings in very recessed areas that you wouldn’t be able to reach with a standard pipe wrench.
• A garbage disposal wrench has a long shaft and a wide, flat head that pivots easily. It’s mainly used to remove the nuts on a garbage disposal. It can also be used to fix a cutter plate jam.

• A hex key wrench or Allen wrench has a hexagonal shaped body. The metal shaft may end in an L-shape or T-shape that serves as a handle. This makes it easier to turn. Hex wrenches often come in a set with several different sizes. Both standard and metric wrench sizes are available.
• A torx key wrench is designed to fit a specific star-shaped depression. It features an L-shaped handle for an easy grip and easy turning. These wrenches usually come in sets featuring varying sizes.
• A crowfoot wrench has a head with a single open end and no handle. The crowfoot wrench head attaches to a torque handle. It is designed to fit at the side of the fastener rather than over the top. This allows the wrench to operate as a socket wrench in tight spots.

As with any tool, it’s important to use it properly. This will help reduce the chance of injury to yourself or damage to a part.

• Wear gloves and safety glasses when using wrenches or other tools.
• Always keep wrenches in good condition. Clean and dry your wrenches before returning them to the tool box after use, and replace any that are damaged or broken.
• Select the correct wrench for the type of job you intend to do.
• When using a wrench, only apply a small amount of pressure at first. Once the fastener begins to loosen, you can apply greater force.
• When using an adjustable wrench, improve your leverage by positioning the tool so that you are turning the fastener toward your body.