Driving fat screws into rock-solid surfaces requires huge muscle-a task even the highest-end cordless drills often can't hack. But the beasts on this page and the next are ready to ease that burden. Twice as fast as traditional cordless drills and three times as powerful-yet only half the size and weight-impact drivers are strong enough to put a beefy screw through a concrete block.
In the past, impact drivers were pneumatically driven units tethered to a compressor, but a recent flood of high-capacity batteries has allowed manufacturers to separate the tools from their air hoses and create cordless electric models. The Craftsman 11458 shown here is the smallest of the bunch, and the most obvious beneficiary of the new battery technology. It'll fit in your kitchen drawer and weighs in at a trim 1.5 pounds.
At times-say, you're driving a screw into a piece of balsa wood-an impact driver acts just like a drill, quietly turning your fastener. But as resistance builds, a spring-mounted, double-headed hammer in the tool's nose cone winds up. When fully compressed, it releases, spins 180 degrees, and smashes against the chuck, creating a massive burst of torque. It's like rapping a wrench with a hammer 50 times a second to loosen a frozen nut. Let's see your drill do that.
Best for the always-on-call handy dad. Barely bigger than a screwdriver, it outpowers some cordless drills.
Max. torque 175 inch-pounds
Max. impacts per minute 3,600
Max. rpm 1,800
Battery 4.8-volt NiCad
Black & Decker BDID1202
Best for the seasonal handyman. Not the most powerful of the bunch but still brawny, this is your choice if you´d rather not spend $200-plus on something you´ll use only a few times a year.
Max. torque 850 inch-pounds
Max. impacts per minute (ipm) 2,800
Max. rpm 2,600
Battery 12-volt NiCad
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.