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, but 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 run times of batteries — how long they will be effective during use — look at amp-hour ratings. More amp-hours and more volts provide longer run time, but the battery charge level, material you're working with, level of continuous use and even temperature affect how long a battery lasts.
A corded drill offers high power and is lighter than a cordless model with similar capabilities. An amp rating represents the power of a corded drill. A steady power supply means greater run time and no need to stop to recharge a battery, but 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 .
Follow the tool manufacturer's instructions for use, maintenance and safety.
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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.
Drills are available in 1/4-inch, 3/8-inch and 1/2-inch sizes. The measurement refers to the size of the drill chuck — the part that holds the bit — and indicates the maximum-diameter bit shank that fits the drill. A 1/4-inch chuck is sufficient for a light-duty driver. A 3/8-inch drill is common for work around the home and accepts a wide range of bits. A 1/2-inch drill handles heavier applications. 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, while 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.
Some drills have keyed chucks which require a tool to tighten and loosen, but many drills have keyless chucks which 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.
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Some bits have stepped-down shanks — the shank is smaller than the diameter of the bit. This feature allows the bit to fit a small chuck, but a smaller drill may not have enough power to bore through dense material.
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More torque allows you to drill through denser materials such as hardwood and metal. If you don't need this power, consider a lighter, more compact drill with less torque.
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Some cordless drill batteries work with other cordless tools and outdoor power equipment.
Any tool should feel comfortable when you use it. A drill may feel great when you first pick it up, but consider what it will 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.
The design of the drill also affects how it feels. There are two common drill handle styles. A T-handle drill features a handle near the middle of the drill body. This design distributes the weight for better balance and less wrist strain. Many corded drills have a pistol-grip design — the handle is at the rear of the drill.
In addition to standard drills, there are other drilling and driving tools you can add to your collection:
?Good to Know
You can find sets that combine drills with other power tools such as impact drivers, hammer drills, reciprocating saws and circular saws.