8 Types of Wrenches Every DIYer Should Know
Tradespeople and DIYers who need to do some cutting use a saw or some type of blade, and those who need to pound something use a hammer. But take it from me (someone with a few decades of home improvement experience under my belt): When it’s time to get down to the nuts and bolts of doing home repair projects, you absolutely need some type of wrench. These tools don’t have as long a history as hammers and saws, but ever since their use became mainstream in the 1800s, wrenches have become indispensable to carpenters, mechanics, electricians, appliance repair techs, and plumbers — as well as to handy people and DIYers.
Unlike hammers, wrenches can have a ton of variety. The types of wrenches you can see come with straight jaws, angled ones, or adjustable ones, and they’re all available in sizes that can fit every possible bolt. Some wrenches also have closed jaws that fit over nuts and bolts to grip them more tightly — because when it comes to wrenches, grip is everything.
If you’re like me (and most other people, too), you probably don’t have room in your toolbox for every imaginable size of fixed-jaw wrench, and you compensate with adjustable wrenches. Even those come in more than one size, however, and you usually need more than one. It’s pretty much impossible to have a single wrench that you can use for every purpose. But you can make sure that you have a small selection that can cover you in almost every scenario. Here’s a rundown of some of the most common wrenches out there and what you use them for.
Open-Ended Wrench
The granddaddy of modern wrenches, an open-ended wrench may have been in the tool collections of some ancient ancestors, who likely made it out of bone. Steel versions came into their own during the Industrial Revolution of the 1800s.
An open-ended wrench has fixed, open jaws that must match the nut or bolt you’re trying to turn more or less exactly, or the jaws will slip when you apply torque. Open-ended wrenches come in metric sets graduated in millimeters or SAE (Standard American English) sets graduated in fractions of an inch. If you need to buy one for a particular job, it’s usually more economical to buy a set. You’ll probably find uses for the ones you don’t immediately need.
These wrenches work best when you have plenty of clearance, and ones made from hardened steel are more likely to resist wear and keep their holding power over time than cheaper ones finished with a bright chrome finish.
Crowfoot Wrench
Separate the jaws from the handle of an open-ended wrench, put a square hole for a handle at the base of the jaws, and you’ve got a basic crowfoot wrench. When you fit a handle with a hinge on the part that you put into the hole, you can orient the handle at various angles with respect to the jaws. This allows you to use the wrench in cramped spaces.
Plumbers use an adjustable version of a crowfoot wrench — called a basin wrench — to reach stuck faucet connections in the tight space behind a sink, where there’s no room for a conventional wrench. Auto mechanics, machinists, and HVAC technicians also use crowfoot wrenches to loosen hard-to-reach nuts and bolts inside engines and machinery.
Box Wrench
A box wrench is basically a closed-end wrench: Instead of opposing jaws, the profile of a box wrench is more like the hole in a donut. The inside edges of the hole are serrated to better grip whatever you’re loosening or tightening, and because of this, a box wrench allows you to exert more force than an open-ended wrench.
Rather than gripping a nut or bolt from the side, as you do with an open-ended wrench, you have to slip the head of a box wrench over it. Once it’s locked on, the wrench won’t slip off (assuming you use the right size). This is an advantage when loosening or tightening fasteners hidden inside machinery, as long as there’s enough clearance above them for the wrench.
Adjustable Wrench
The first wrench patented in North America was an adjustable wrench — a version of the coach wrench which was in common use in England at the time. One jaw moves with respect to the other fixed one, which allows you to use the wrench with a variety of fasteners of different sizes. A thumbscrew advances the movable jaw, and the quality of the tool depends on how precisely ground this thumbscrew is, as well as the type of steel from which the tool is made.
The familiar spanner is an adjustable wrench with jaws oriented parallel to the handle. Monkey wrenches are adjustable wrenches that have jaws arranged perpendicular to the handle rather than parallel. Plumbers’ wrenches look like spanners, but they have extra-long jaws good for gripping pipe fittings.
Adjustable wrenches — even good ones — don’t fit as tightly onto nuts and bolts as wrenches with fixed heads, and they are bulkier, so they aren’t really suitable for precision work. They are great utility tools, though.
Ratchet Wrench
A ratchet wrench is a box wrench with a mechanism around the edges of the “donut hole” that grips in one direction (usually clockwise) and slips in the opposite direction. This allows you to turn a nut or bolt through several revolutions without removing the head of the tool from the fastener.
You can probably already imagine how useful this ratcheting action is. Instead of wasting time and effort repositioning the wrench whenever something gets in the way of the handle, you simply reverse the handle back to its starting point and keep turning the fastener.
You can use a ratchet wrench in pretty much any situation in which you would use a regular box wrench. It makes the job go faster and eliminates the frustration of having to reposition the wrench head multiple times while working in tight spaces.
Combination Wrench
Any wrench that has one type of head on one end of the handle and a different type of head on the other is a combination wrench. The combinations can be open-ended on one end, box on the other, open-ended/ratcheting or box/ratcheting. A wrench that has the same type of head on both ends — but of different sizes — could be considered a combination wrench, but the term usually only applies to wrenches with different types of heads.
Mechanics and machinists are the tradespeople most likely to need a combination wrench, because the variety of situations you encounter when working on engines or machinery call for the added functionality it provides. It’s a tool that comes in handy around the house, though, as you can use it for double the applications — and it’s a good addition to any DIY toolbox.
Pipe Wrench
Some people refer to pipe wrenches as monkey wrenches, but they are completely different tools. Instead of the smooth, flat jaws that a monkey wrench has, a pipe wrench has serrated jaws, and they are arranged at a slight angle to each other. This allows the jaws to grip pipes and other objects with smooth surfaces.
No plumber would be without a pipe wrench. You need one for screwing and unscrewing threaded pipes, loosening oversize nuts, and much more. Pipe wrenches are made of heavy cast iron, so you can apply a lot of torque to one without the danger of breaking it.
Allen Wrench
An Allen wrench, also known as a hex wrench or Allen key, is probably something you recognize from your IKEA furniture builds. It’s completely different from other types of wrenches, because it doesn’t have jaws. It’s an L-shaped tool with a hexagonal profile, and it’s designed to fit inside a hex-shaped slot. You insert the short end of the “L,” and use the long end as a lever to loosen or tighten the fastener.
DIYers absolutely need to have a set of Allen wrenches, because manufacturer-supplied fasteners for towel racks, faucets, and many other types of home furnishings are hex screws. When you purchase ready-to-assemble furniture, the fasteners that come with it are often hex screws for which you need an Allen wrench, and an Allen wrench is the tool you use to free a stuck garbage disposal.
If you need an Allen wrench for a particular task, it’s better to buy a set than an individual wrench. Sets aren’t expensive and, as with sets of other types of wrenches, you’ll probably eventually find uses for the sizes you didn’t use for the task at hand.
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