Cordless drills are available with similar features to an AC mains-powered drill. They are available in the hammer drill configuration and most have a clutch, which aids in driving screws into various substrates while not damaging them. Also available are right angle drills, which allow a worker to drive screws in a tight space.
How to choose
| 1. Not everyone needs maximum power and run time. Nearly any drill will do for hanging pictures and other easy tasks. Decide how much speed and power you really need. And don't buy strictly by voltage. 2. Besides checking the drill's weight, check its balance by gripping it firmly and lifting it to a wall as if to drive a screw. 3. For kits, check all the tools. Most cordless tool kits include a drill, reciprocating saw, and circular saw. But while cordless circular saws have improved,some of those and reciprocating versions have been unimpressive and proved to be slow and weak. 4. Weigh the pros and cons of specialized drivers. You'll also see more Li-Ion impact drivers and small, lightweight cordless screwdrivers that weigh one pound or less. But our tests revealed some notable drawbacks. | |
Batteries
| Common battery types of are nickel-cadmium (NiCd) batteries and lithium-ion batteries, with each holding about half the market share. NiCd batteries have been around longer, so they are less expensive (their main advantage), but have more disadvantages compared to lithium-ion batteries. NiCd disadvantages are limited life, self-discharging, environment problems upon disposal, and eventually internally short circuiting due to dendrite growth. Lithium-ion batteries are becoming more common because of their short charging time, longer life, absence of memory effect, and low weight. Instead of charging a tool for an hour to get 20 minutes of use, 20 minutes of charge can run the tool for an hour. Lithium-ion batteries also hold a charge for a significantly longer time than nickel-cadmium batteries. | |
Types
| Cordless drills | These are best for fast drilling and most screw-driving. NiCd-powered models can handle most jobs, but Li-Ion and NiMH tools performed best in our tests. The 18-volt drills (typical these days) weigh about twice as much as 9.6-volt models. |
| Cordless impact drivers | These are best for driving long fasteners or loosening stuck ones, thanks to their added torque, or twisting force. Most can handle the lug nuts on car wheels and other tough tasks without twisting out of your hands. But they typically require hearing protection. They also require special hex-shank bits for drilling holes, and have been slower than most cordless drills in their drilling mode. |
| Cordless screwdrivers | These models are small enough to fit in your pocket and typically weigh one pound or less. Bendable power heads make them convenient for tight spaces, and the lithium-ion batteries in some offer added efficiency. But cordless screwdrivers are typically adequate only for the lightest of tasks. You'll find more-capable, if larger and heavier, drills for the same or less money. |
| Cordless tool kits | Along with a drill, reciprocating saw, and circular saw, many kits include a work light and, for some, an auxiliary tool. And all share the same battery, which helps to make kits less expensive than the tools, batteries, and chargers would be if bought individually. But our tests revealed significant differences in performance, especially when the price dips below $300. Indeed, you could wind up with a collection of sub-par tools. |
Features
Battery charger
A "smart" charger on many models can recharge the battery in 15 to 60 minutes, compared with three to five hours or more for conventional chargers. It also helps to extend battery life by adjusting the charge as needed. A few models can charge two batteries at once, which is handy for big projects. The box typically lists the recharge time.
Battery-charge indicator
More models now have a meter that indicates the remaining charge. This feature is especially helpful with lithium-ion batteries, which can be damaged if you allow them to run down fully before recharging.
Chuck size
Many cordless drills have a 3/8-inch chuck, but heavier-duty models have a 1/2-inch chuck for larger, 1/2-inch drill bits. Note that large-diameter bits are available with a reduced shank to fit smaller chucks.
Speed ranges
Many cordless drills have a low speed range with more torque, or twisting force, for driving screws and a high-speed range with added speed for drilling. All have a variable-speed trigger to make starting a hole easier, and most have an adjustable clutch that reduces maximum torque to avoid driving a screw too far into soft wood or wallboard. All are reversible, which is handy for freeing a stuck drill bit.
Extra handle
Some models have a second, side handle so that you can hold the drill with two hands, which is helpful for counteracting twisting force when tightening or loosening.
Built-in LED work light
This can be handy in dark places, flooding the work area with light. Many kits include a separate work light.
Kits
Most makers bundle their drills with other tools in kits that typically include circular and reciprocating saws and a flashlight in a carrying case. Some kits are a good deal, while others are a collection of mediocre tools.
Brands
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Written by Nicolas Yang
