Source: TOOLS OF THE TRADE Magazine
Publication date: August 8, 2011
Manufacturers refer to their subcompact models as 12-volt tools, but the battery packs contain three 3.6-volt cells, making them a nominal 10.8 volts. The higher voltage number refers to the maximum charge the pack can take and does not equate to what it puts out.
A cordless tool should be able to do a reasonable amount of work per charge; otherwise you'll outpace the charger. To find out what the drill/drivers could do, I ran them to exhaustion (or until the electronics stopped the motor) while performing a variety of driving and drilling tasks. Using 1-3/4-inch test planks as the substrate, I drove 1-1/2-inch-long #8 screws in low gear, bored 3/4-inch holes with self-feeding bits in low gear, and drilled 1/2-inch holes with spade bits in high gear. To avoid overheating the batteries, I drove 11 screws at a time (one row across a 12-inch-wide test plank) and then let the tool rest for several minutes. The holes were bored in groups of five (top chart, previous page).
I tested the impact drivers to battery exhaustion in separate high- and medium-load tests by driving 1/4-inch-diameter Simpson Strong-Tie SDS lags into test planks. I drove 3-1/2-inch lags six at a time (before resting) and 1-1/2-inch lags 10 at a time (center chart, previous page). For the sake of comparison I repeated these tests with the Ridgid impact driver but drove the lags into solid framing lumber. The Ridgid drove about 25 percent more fasteners per charge in framing lumber – which made sense, because the test plank material was very hard. It's reasonable to assume this result would apply to every impact tool and that runtime in framing lumber would be about 25 percent better than my results.
Although all of the tools in the test fit perpendicularly in a 12-inch drawer base – convenient for tasks like attaching drawer slides – some leave more wiggle room than others. At just under 5-1/2 inches long, the Bosch is the shortest of the impacts. DeWalt's impact tool is not the most compact model on the market, but its unique ability to take a 1-inch bit makes it as short in use as the Bosch.
Drill/drivers are longer front-to-back than impact drivers, but the Bosch and Ridgid drill/drivers come close to being as short as an impact.
Comfort and balance. The skinny handles afforded by slide-mount and tower batteries feel instantly comfortable, because you can wrap your fingers all the way around them. However, wider, fatter handles – though they may feel clunky at first – provide much more surface area to push your palm against when you're actually using the tool. Don't buy a tool without testing how comfortable it feels – not just when you're holding it in the air, but also when you're pushing hard on the handle.
Balance is often an overrated concern as it deals only with how the tool feels when you're not using it. A nose-heavy tool can be a bit of a nuisance to line up with a hole or screw, but as soon as you engage the work, it's the bit that's supporting the weight. Most of the tools have T-handle designs and feel very well-balanced. The tools with more L-shaped handles – Rockwell's drill/driver and the Festool when the three-jaw chuck is in place – are noticeably nose-heavy. The Ridgids feel top-heavy but are well-balanced front-to-back.
The Bosch and DeWalt impact drivers have triple-LED headlights (left). Subcompact drill/drivers and other makers' impact drivers rely on a single LED light below the chuck or bit holder (right).
Standing ability. It's great if the tool can stand on its own, because that makes it easier to put down and pick up with one hand. Most of these tools can be made to stand upright, but their balance is very precarious. A few have broad, flat bottoms that make them more stable when standing.
Belt clips. A belt clip is handy for holding the tool when you're walking around or climbing a ladder. The DeWalt, Festool, and Porter-Cable models come with reversible, removable belt clips.
Headlights. The Bosch and DeWalt impact drivers feature triple-LED headlights, with DeWalt's being the brightest by far. To light up a shadowy cabinet interior or line up a screw without spinning the bit, all of the brands except Rockwell have a basic flashlight function that you activate by slightly depressing the trigger. On the Makita tools and the Ridgid drill/driver, squeezing the trigger causes the light to stay on for 10 and 18 seconds respectively, which makes the function easier to use. The best lights completely illuminate the head of the fastener, so you can see where you are putting the driver bit.
Fuel gauge. One feature I think no cordless tool should be without is an onboard battery fuel gauge. The Bosch and Milwaukee tools have simple LED bars that tell you the state of charge in an instant. In addition to sparing you a frustrating trip out of the crawlspace, this can keep you from needlessly charging your batteries and shortening their life.