The cordless impact wrench is quickly gaining in popularity among professional mechanics and the hobby mechanic as well. You may be thinking "I already have a cordless drill that I use for impact applications, why do I need a cordless impact wrench as well?". I thought the same thing. The first difference is on the inside. A cordless drill creates continuous in-line torque. A cordless impact wrench employs an internal spring-loaded pulsating cam to create rotational torque. This creates the "impact" force that loosens a nut. It is the equivalent to banging a wrench with a hammer to loosen a rusty nut only a lot faster. Unlike a cordless drill – which creates continuous in-line torque, a cordless impact driver uses an internal spring-loaded pulsating cam and gear mechanism to create rotational torque or the "impact" force.

Another big difference, is the lack of reactionary torque. Reactionary torque is what you experience with your cordless drill. You have to use brute force to keep your drill from spinning the opposite direction in your hand. With a cordless impact wrench, that torque is directed to the nut not your arm. You can easily hold this tool in one hand and let the cordless impact do all the work. No more pushing down on the tool to drive that screw. These tools are also smaller and lighter than a cordless drill. For example a DeWalt cordless impact wrench is about 35% the size of its comparable cordless drill. This feature makes them perfect for those overhead projects and reaching into hard to get to spaces.

The next time your start that big deck project in the backyard, leave the cordless drill in the box and grab your cordless impact wrench. Your arm will thank you at the end of the day.

Popular Wood working did a test on cordless drills and this is what they said. After testing 16 professional and consumer model cordless tools, we know that 12 volts is enough for woodworkers, and there are lots of quality power tools to choose from.

Cordless drills are pretty amazing. They’re portable, pack lots of power and have features that most corded drills don’t offer. Cordless power tools get less expensive every year, and the competition is so tight that there are lots of great power tools available. But cordless tools are not all created equal, and we tested a bunch of them so we can tell you which cordless drills to buy.
For our test we completely discharged each battery, then recharged, then discharged the battery again. After one more complete charge we were ready to test. For the first test we took a brand new 1?2" Speed bore spade bit (one for each cordless drill) and started drilling holes completely through 11?2"-thick poplar boards.

Because the amount of force and speed applied in a drilling process can alter the results in such a test, we had two editors (one male, one female) repeat the tests, then we averaged the completed holes on one battery charge. All cordless drills were tested in the high-speed range setting (when available) and with clutches set to zero torque resistance (or screwing mode). For the second test, we sank 1?4"-diameter by 11?2" – long lag bolts into 11?2"-thick cabinet-grade plywood. This test was performed with the power tools speed setting on low, providing maximum torque, and again with the clutches set on zero torque resistance.

Finally we took a look at the ergonomics of the power tools. Each member of our staff evaluated the grip, balance, ease of use for the battery release, chuck, clutch and variable- speed triggers, and came up with an average rating for each cordless drill. We then averaged all the individual scores and came up with an ergonomic rating for each cordless tool. We also decided to divide the cordless drills into consumer and professional categories to fairly compare cordless tool to cordless tool, but our testing also lets you see how the consumer models compare to the pro’s .