The drill goes all the way back to Paleolithic times when cave men used a flint point attached to a stick and rubbed between the palms to make holes through bone, ivory, shells, and antlers. The electric drill is much more modern than that, but is still the oldest hand-held electric power tool there is.
Early models were housed in heavy cast-iron casings, making them difficult to use. During World War II, Henry Ford made a request of one of his tool suppliers, A.H. Peterson, that they develop a lightweight electric drill for use on the assembly line. The Peterson Company came up with the first practical handheld electric drill which Henry Ford made good use of.
Unfortunately, the Peterson Company didn't survive, but their drill did. When they went under, the assets were bought out by one of the partners who formed the Milwaukee Electric Tool Company. Incidentally Milwaukee Tools still makes some of the best electric drills on the market.
The electric drill has grown in use, not only by popularity, but by the development of additional ways to use the drill. Today, electric drills are used for cutting holes, polishing, and sanding in addition to the more traditional use of drilling holes. Even within the realm of drilling holes there are a variety of drill bits available for drilling different types of holes or drilling into different materials.
Today, the trend is more and more towards cordless drills. With their high capacity and fast recharge Li-Ion battery technology, a cordless drill can be used almost constantly simply by swapping batteries and recharging them. Although Li-Ion battery powered tools are still a bit expensive, they’re well worth it to those who need to use their drill a lot. For others, there are cheaper options they can consider, including lower voltage cordless drills and corded drills.
Hand-held Drill Types
There are more types of electric drills on the market today than ever before, along with many ways of categorizing them. But the simplest ways of categorizing them are by price, size, power and whether or not they have hammer action.
Corded Drills
Originally, all handheld electric drills were run off of AC house current. These are still available today but are rapidly losing market share to cordless drills. However, for the homeowner who doesn't use a drill very often, a corded drill is still better than waiting for the battery to charge in their cordless drills. Corded drills are also very useful in operations where the drill must be on for prolonged periods of time, which would run down the battery, such as using a wire brush.
Cordless Drills
Cordless drills are taking over the market from corded drills, due to their convenience of use. With modern battery technology, Lithium Ion batteries hold a higher charge and have a shorter recharge time, allowing the drill to be used much more, with less time lost to recharging. Cordless drills have also become more powerful, rivaling their corded cousins.
Cordless drills are almost always drill/drivers, meaning they have a built-in clutch to disengage the drill chuck from the motor. If you’re using it to drive screws rather than drill holes, the clutch can help prevent overdriving the screws to too great a depth.
Right-Angle Drills
These are a special new category of cordless drills, designed for use in tight places. The right-angle gearhead allows the overall drill length to be as little as about three inches, plus the length of the drill bit. This allows for drilling in otherwise inaccessible areas.
Hammer Drills
Hammer drills are predominantly used for drilling through stone, concrete, and masonry. They’re also the best drill for cutting through ceramic tile. The drill has a built-in hammer which provides a blow every revolution, much as if you were hitting the back of the drill with a hammer. This allows the special masonry bits to chip through the substrate you’re trying to drill through. Hammer drills always have a switch to turn the hammer action off when not needed, so the drill can be used for normal drilling operations.
How Does Price Affect the Drill?
When you look at a selection of drills, you'll see a wide variety of pricing, sizing and options. This can be a bit confusing, especially when buying your first drill. Cutting through all the fog, what you're really paying for in the more expensive drills is power and quality. Of course, things like a hammer action and a right-angle head will add to the cost as well, but when comparing standard drills, trying to make an apples-to-oranges comparison, higher price equals more power and better quality.
Contractors and construction workers who use their power tools all the time need implements that will take a beating for years and still keep working. You may not need that rugged a drill for your home workshop but you also have to consider the difference in power between different drills. This can be difficult to compare as not all manufacturers give the same types of specifications for their products' power.
Cordless drills are also more expensive than corded ones due to the cost of the batteries and charger. However, with most of the major power tool manufacturers you can buy bare tools without batteries and chargers. This allows you to use the same batteries across several power tools, assuming you have a number of power tools that use the same voltage batteries and were made by the same tool manufacturer. Bare tools are often about as cheap as their corded cousins.
Other Options to Consider
Most people who do a considerable amount of do-it-yourself projects ultimately end up with more than one electric drill. While they might have one primary drill (usually a cordless drill/driver), they end up collecting others along the way. This is actually an advantage on many projects, as you might have to drill holes, countersink them and then put the screws in. If you only have one drill, that's a lot of bit changing to do.
The Chuck
Today's drills are almost all manufactured with keyless chucks. These are much easier to use, but may have problems staying tight, especially in cases where there’s a lot of vibration. Ratcheting chucks are better at avoiding the problem of loosening than standard ones are as well as keyed chucks. But keyed chucks are only going to be found on very large drills.
Chucks can vary in size from 1/4" to 1/2", with 3/8" in between. This dimension refers to the largest diameter drill bit shaft they are designed to accept. In the case of smaller drills, they probably don't have sufficient power to use the larger sized drills, which explains why they don't have those larger chucks.
Integral Work Lights
Cordless drills also typically have work lights mounted on them, which are a very useful option. The location and number of LEDs used for the work lights is important as it affects where shadows form. Some manufacturers also give you the option of turning on the work light before drilling which is very handy.
Secondary Handle
Hammer drills and other larger drills will also have a secondary handle, to help stabilize the tool and prevent the torque from hurting your wrists. Some of these tools can put out a lot of torque, enough that in the case the bit jams you could become injured.