How to Buy a Cordless Screwdriver

Choosing a cordless screwdriver

Woodworking and construction experts recommend choosing the smallest, lightest cordless screwdriver that will get the job done -- your best choice depends on the size screw you drive most often. In addition to minimizing fatigue, which can occur even when driving small screws, a compact screwdriver makes it easier to work overhead or inside a cabinet. If you take on many varied projects, you may want a tiny cordless screwdriver for small screws only an inch or so long, plus a subcompact driver for longer screws up to about 2.5 or 3 inches.

Cordless screwdrivers are roughly categorized by battery size and thus, their power. Subcompact drivers -- sometimes called pocket drivers after the Bosch tool that started this category -- use batteries rated at 10.8 to 12 volts. (Most 12-volt tools peak at that voltage, but actually work steadily at 10.8 volts.)

Smaller, lighter cordless screwdrivers generally use batteries rated at 3.6 to 6 volts. Cordless screwdrivers also come in a variety of shapes and styles.

Reviewers say the following features matter most when selecting a cordless screwdriver:

• Try drivers in person if possible. Because hand size varies among individuals, experts recommend testing more than one screwdriver if possible. Make sure the tool feels balanced, not top-heavy or front-heavy. Even a lightweight tool can cause fatigue if it doesn't feel right in your hand.

• Look for a fast, smart charger. Many cordless tools come with 30-minute or even 15-minute chargers, which means that a set of two batteries can keep you working as long as you want. A smart charger lets you know how charging is progressing, and then turns itself off to prevent overcharging.

• Go for Li-ion batteries. Li-ion batteries are lighter and more compact than Ni-Cd or nickel-metal hydride (NiMH) batteries, making them ideal for screwdrivers. Li-ion batteries also run longer and hold their charge a long time between uses -- a big bonus if you use your driver infrequently.

• Opt for a kit with two batteries if you have a lot of bigger jobs. A cordless screwdriver with a fixed battery cannot be used while recharging, whereas drivers with removable batteries let you charge one while you use the other. If the charger is fast enough, you can keep driving screws as long as your arm holds out.

• Choose a model with a meter on Li-ion batteries. This type of battery keeps the tool running at full power until recharging is needed, but this means you need some warning when that time approaches. The best Li-ion cordless tools build a charge meter into the battery.

• Think about weather. Some brands handle very cold weather well. If you might store or use your screwdriver in sub-freezing weather, pick a tool with batteries that recharge and work well, even after exposure to extreme cold.

• Cross-check manufacturer torque claims against expert tests. Reviewers say objective tests are more accurate for measuring torque than manufacturers' claims. Torque (in inch-pounds) is the basic measure of the amount of twisting force the drill or driver applies. Usually, higher voltage means more torque. Note, however, that different models with the same voltage do vary.

• For convenience, buy a model with a one-handed chuck. This means a bit can be locked in using one hand -- useful when you're holding work in place with the other or working in tight quarters.

• Look for soft padding. Overmolding can make the handle more comfortable, and some rubber or soft plastic on the tool itself can protect both the tool and surrounding surfaces from damage if your driver slips or falls.

• Gain control with a variable speed trigger, speed ranges and a clutch. It's possible to strip a screw head even with a low-voltage cordless screwdriver. Be sure the driver provides the control you need.

• A built-in LED light is a nice bonus. This feature helps when driving screws inside a cabinet or closet. Reviewers say some LEDs illuminate the work area better than others; a light that stays on a few extra seconds is helpful in making sure the screw is well seated.