The 7 Best Corded Impact Wrenches
7. Craftsman 927990
6. Capri Tools 32200
5. DeWalt DW292
4. Topcraft Dragon
3. Kobalt 6904
2. Makita 6952
1. Hitachi WR16SE
The Tools Make The Man (or Woman)
Humanity has come a long way since the days of crafting hammers and spears out of sticks and rocks. Indeed, the tools we have used throughout history serve as reliable markers of just how developed our society is. During the Renaissance, scientists classified some of the most basic systems for altering how force is applied to objects. These tools are called simple machines. The screw, and by extension the bolt, is unique among these six original designs in that it's a combination of two others. A screw is actually an inclined plane wrapped around the axle of a wheel-and-axle machine.
While researchers and craftsmen have used simple and complex machines throughout human history, the material used and the strength of the force applied have changed dramatically. Rarely today are wooden pegs used to hold quality furniture together outside of Amish country. Powerful equipment like cars, generators, drill presses, and 3D printers are made of high-strength steel components held together with hundreds of foot-pounds of torque.
From the stone age until beyond the Industrial Revolution, superhuman levels of torque were generally hard for the average laborer to achieve. But when the 21st century home repairman needs to secure 16 lug nuts in a hurry, they're in luck. For the last few decades, DIY enthusiasts have rejoiced in the availability of powerful, compact, inexpensive power tools.
It's easy to see how adding 110 volts of power can add a lot to any project. But what about the rusted lug nuts, frozen bolts, and concrete-sunken screws? An everyday hand ratchet and socket set just doesn't offer the mechanical advantage needed to disassemble and rebuild large machinery. An electric drill simply won't provide the oomph to turn that nut that hasn't spun freely since 1978. Sure, a long breaker bar might do the trick, but that takes a lot of elbow grease, and might not even be adequate. The answer to this problem may be an impact wrench.
A Lot More Than A Screwgun
We know that hand tools can't always get the job done when constructing or repairing large equipment. But does your workshop really need an impact wrench, or can you use an everyday drill or electric screwdriver to drive and remove heavy screws, nuts, and bolts? The answer lies in friction.
Static friction is the amount of force that a surface exerts on a stationary object, preventing it from starting to move. Sliding friction is the resistance that object experiences while it's moving across a surface. And these forces have everything to do with tightening lug nuts.
While a nut, bolt, or screw is being drilled into inches of concrete, sliding friction between the medium and the fastener eventually reduces the kinetic energy of the screw until it stops turning. At this point, even if you increase the constant pressure by turning up the screwgun or pulling on the wrench harder, you're unlikely to turn the screw any farther. This is because the static friction in the system has become greater than the force applied by your tool.
So, you're pulling with all your might and still can't break that last rusted bolt free. But if you hit the end of that wrench with a hammer several times, you just might succeed — and that's exactly how an impact wrench works. A strong motor spins a driveshaft with a massive amount of torque. At the end of that shaft is a mechanism that catches at specific points in the shaft's rotation, rather than the fixed gears that provide a standard drill with constant force. The result is rapid bursts of high-powered rotation that easily overcome static friction, turning that screw much more quickly and safely than a breaker bar and a sledgehammer can.
A Good Tool Makes A Huge Impact
With the growing popularity of in-home construction projects, there are more options than ever for building your power tool collection. The standard type of power used in a lot of high-torque tools, particularly impact wrenches, is compressed air. Moderate to heavy-duty air compressors can give your workshop a lot of power and are very durable, but there are a few drawbacks. They can be expensive; they do sometimes require maintenance; there's a warm-up period while the air pressure builds; and, most apparently, they're really loud.
But there's a simple solution to this, and it comes in the form of electrically powered impact wrenches. These units plug into any grounded (three-prong) 110-volt socket and provide incredible versatility while making far less noise than their pneumatic counterparts. They also vibrate considerably less during use, making the job that much safer and easier on your hands and joints.
A quality impact wrench should have a standard 1/2-inch drive, but some top models boast a heavy-duty 3/4-inch size for added security. Be certain to use high-hardness sockets and adapters that are specifically designed for impact wrenches to keep from snapping or shearing those made of weaker steel. Breaking tools can be costly, time-consuming, and dangerous.
When comparing impact wrench choices, pay careful attention to the options you're considering. While they're a similar concept, impact drivers have much lower torque and often utilize a 3/16-inch bit, so they can't serve the same heavy-duty purpose as actual impact wrenches can. Also, keep in mind that impact wrenches provide massive power, but it's not usually well measured and can sometimes make things too tight. In some situations, you'll need to follow up the impact wrench with a torque wrench. You could also try a hammer drill, a tool very similar to an impact hammer that usually offers variable speed and torque control for more intricate jobs.
All in all, there are more brands than ever to choose from, and some of the most familiar companies are still making great products. The home handyman and the professional mechanic have never had such great selection.