Impact drivers are ideal for working with large fasteners or driving screws without a pilot hole, and they can drive more screws at faster speeds than a cordless drill. Though they look like a drill, impact drivers are very different internally. Instead of rotating -- like a cordless drill -- an impact driver uses a series of rapid, successive blows when it senses resistance. This creates two to three times the amount of torque of a cordless drill, allowing you to power through tough projects without straining your wrists or forearms.
In place of the keyless chuck, which can be adjusted to hold a variety of bits, impact drivers have a fixed chuck that only holds hex-shanked bits. Because they are noisier and heavier than cordless drills (and unable to drill holes), these are a drill's companion, not replacement.
Mechanics, contractors and homeowners with a large project -- like building a deck or laying a new floor -- say an impact driver makes their job faster and easier. The best cordless impact drivers are compact for easy handling, have a battery with adequate run time and have good trigger control.
The Milwaukee 2650 compact cordless impact driver places first in professional tests and with consumers. It is available as 2650-21 (*Est. $225) with the compact 1.5-Ah batteries or as Milwaukee 2650-22 (*Est. $280) , with longer-running 3.0-Ah batteries.
"Compared to Makita 18v Li-ion, DeWalt 18v Li-ion and DeWalt 20v Li-ion, the Milwaukee 2650-21 drives screws and lags and other fasteners much faster and with much less user input," says a user at HomeDepot.com. This impact driver gets nearly perfect ratings from a handful of owners at HomeDepot.com and Amazon.com, but a few reviewers say the variable speed can be tricky to tame.
The Milwaukee 2650-22 is a top runner-up in tests at Tools of the Trade and Popular Mechanics. It drives 3 .5-inch lag bolts faster than any other impact driver in Tools of the Trade's test, and only two other contenders drive more lags per battery charge. Popular Mechanics finds the same thing -- the Milwaukee drives the most lag screws in a time trial -- and tester Roy Berendsohn calls it "a lag-driving powerhouse." He also likes that it's "ruggedly built."
For an impact driver that is easier on your budget, The Milwaukee 2450-22 (*Est. $140) surprises owners, and even some pro builders and mechanics, by packing enough power and run time to keep up on the job site. Reviewers at Tools of the Trade say outstanding driving speed and battery run time are two of the reasons why the 2450-22 is in their top three overall; they test it in a comparison of nine 12-volt impact drivers. Pros appreciate the 12-volt Milwaukee's light weight (2.3 pounds), especially for overhead jobs like hanging ceiling drywall and installing windows.
All three Milwaukee impact drivers come with a strong LED task light that has an eight-second delay, battery fuel gauge, two Li-ion batteries, a 30-minute charger and a five-year warranty.