Power Drill Buying Guide

Power, mobility and weight are all considerations in choosing a drill. A cordless drill offers high mobility and a wide range of available features. Voltage ratings of 4 to 8 volts are sufficient for light-duty cordless screwdrivers, and drills with 12 to 18 volts will meet most homeowners' work needs. A high-power model handles heavier work, but more voltage means the tool has a bigger, heavier battery. A cordless drill battery needs recharging periodically. You may want to have a spare battery available so you can keep working while you recharge. To compare the runtimes of batteries — how long they'll be effective during use — look at amp-hour ratings. More amp-hours and more volts provide longer runtime. Keep in mind that battery charge level, the material you're working with, the level of continuous use and even temperature affect how long a battery lasts.

A corded drill delivers high power. While lighter than a cordless model, it offers similar capabilities. A steady power supply means greater runtime, with no need to stop to recharge a battery. However, the cord does restrict mobility. Depending on how far your work area is from a power outlet, a corded drill may need an extension cord. Follow the manufacturer's instructions for selecting a proper cord and see Power Cord Safety Tips.

Common cordless drill battery types include nickel cadmium (NiCd or NiCad) and lithium ion (li-ion). A li-ion battery is lighter and smaller than a NiCd battery of the same voltage. Li-ion batteries can hold a charge for several months between uses.

Some capabilities are necessary for certain tasks, while some simply make the work easier. Here are some considerations when choosing a handheld power drill:

• Size: Drills are available in 1/4-inch, 3/8-inch and 1/2-inch sizes. These measurements refer to the size of the drill chuck — the part that holds the bit — and indicate the largest bit shank that'll fit the drill. A 1/4-inch chuck is sufficient for a light-duty drill driver. A 3/8-inch drill accepts a wide range of bits, making it versatile for common tasks around the house. A 1/2-inch drill handles heavier applications.
• Speed: A variable-speed drill with an adjustable clutch gives you versatility for drilling different materials and using a variety of bits. Drilling softwood, hardwood, metal and masonry all require different speeds and torque, or rotational force. Harder materials and larger bits require lower speeds and more torque. Higher speeds and lower torque work with softer materials and smaller bits. The drill trigger controls the speed. You set the clutch to the desired torque level. A properly adjusted clutch keeps you from driving a screw too deep and reduces the possibility of stripping a screw head or snapping a screw off. Drills with a gearing switch allow you to set the drill gearing for low speed and high torque or high speed and low torque.
• Efficiency: Some drills have keyed chucks that require a tool to tighten and loosen, but many drills have keyless chucks that you can tighten or loosen by hand. If you need to repeatedly change between a drill bit and a driver bit, a keyless chuck makes the job quicker and simpler, particularly if the chuck allows adjustment with a single hand.

• A brushless motor offers high efficiency, resulting in better runtime, more power, greater durability and less maintenance. A drill with a brushless motor will also be lighter and quieter.
• Power output is another rating of the power capability of a drill. A units-watts-out (UWO) number measures the output as a combination of speed and torque.
• A built-in light helps you see where you're drilling or driving.
• A built-in level helps you drill and install fasteners more accurately.
• An adjustable side handle lets you perform heavy drilling with more stability and control.
• Accessories can include cases, spare batteries, drill and driver bit sets. If you're shopping for a cordless drill, see if it comes with a charger. Note that bare-tool drills don't come with a battery or charger.

Any tool should feel comfortable when you use it. A drill may feel great when you first pick it up, but consider what it'll feel like after a few hours of use. Think about the work you need to do, and balance the power you want against the size and weight you can comfortably handle.

A drill's design also affects how it feels. There are two common drill handle styles. The handle of a T-handle drill is near the middle of the drill body. This design distributes the weight for better balance and less wrist strain. Other corded drills have a pistol-grip design, with the handle at the rear.

In addition to standard drills, there are other drilling and driving tools you can add to your collection:

• Right-angle drills allow you to work in tight spaces such as between floor joists. The chuck on a right-angle drill is mounted at a 90-degree angle to the drill body.
• Impact drivers can handle heavy-duty driving tasks. The impact action applies more torque than a standard drill mechanism.
• Hammer drills, or rotary hammers, combine the rotation of a regular drill with a pounding action. These two forces allow you to quickly bore holes in masonry.
• Air drills are contractor-grade tools that run on compressed air rather than electricity. These drills require an air hose connected to a suitable air compressor.
• Drill presses are bench-top tools that can create precisely spaced holes and simplify boring to exact depths. With the right tool and proper adjustment, you can bore at almost any angle without fear of the drill bit walking or reaming the hole out of round.
• Powered screwdrivers range from light-duty models for household chores to high-power tools for installing drywall or decking. Some models can be modified to operate in either a pistol-grip or straight, inline configuration.