When Black and Decker created the first cordless drill in 1961, it was little more than a toy. The 1/4-inch drill would drain its battery quickly, take overnight to recharge, and was poorly balanced. But it started a cordless tool revolution and a lot has changed in fifty years. With improved batteries and better tool design, todays’ cordless drills offer much more and at starting prices less than the $60 of that first Black and Decker.

Chuck Size
The chuck size of a drill determines what’s the largest drill bit shank it can accept. For cordless drills you have a choice of either a 3/8-inch or a 1/2-inch chuck. While 1/2-inch drills are usually more powerful, they also weigh more. And the longer you have to use the drill continuously, the heavier it’s going to seem.

Since most home jobs can be handled with a 3/8-inch drill, this is the more popular choice. And if you should need to occasionally drill holes larger than 3/8ths, there are large diameter drill bits with a shank to fit a 3/8 drill.

Choose the Drill Handle Style
Cordless drills have two types of handle design, pistol-grip and T-handle. Like the first Black and Decker drill, pistol-grip drills have the look of a corded drill minus the cord with the battery inside the handle. But T-handle drills attach the battery offset at the bottom of the handle. This configuration improves the drill’s balance and is the design most people prefer.

Choose the Power
The power (torque or twisting force) of a cordless drill is primarily determined by its voltage. So an 14.4-volt drill is usually more powerful than a 12-volt drill. Most drills are rated from 7.2 to 18 volts.

Cordless drill batteries are a package of 6 or more 1.2-volt batteries combined to deliver the required voltage. So as the drill’s voltage increases, so does the weight of the battery pack. Either a 12-volt or 14.4-volt drill should handle typical homeowner demands.

While the battery voltage determines the power, the battery’s amp-hour (Ah) rating indicates how long it can run between rechargings. A 2.6Ah battery should last twice as long as a 1.3Ah rated battery. However, unlike doubling a battery pack’s voltage, doubling its amp-hours doesn’t require twice as many of the 1.2-volt batteries. Instead the pack’s batteries are a higher capacity with no noticeable weight increase.

Battery Type
Since the first cordless drill was invented, most drills have been powered by nickel-cadmium (NiCd) batteries. However, Lithium-ion (Li-Ion) and nickel-metal-hydride (NiMH) batteries are becoming popular alternatives. They offer better performance for a given weight than NiCd batteries and are even less toxic to the environment when disposed.

Along with the benefits of NiMH and Li-Ion batteries comes a higher cost than NiCds. Additionally, Li-Ion batteries don’t perform well in cold weather and may not recharge if they are totally discharged.

Speed Ranges
One of the innovations brought to modern cordless drills is dual speeds. The low speed provides more torque for driving screws and the high speed makes for cleanly drilled holes. To help with starting screws or drilling a hole, the power trigger provides variable speed control with either speed. Both speeds are reversible which is especially helpful for loosening a stuck bit.

Other Types of Cordless Drills
In addition to regular cordless drills there are impact and hammer types. Both provide increased torque over regular drills, but are designed for specialized uses and aren’t needed for most DIY projects.

Extra Features

• If you plan on using other cordless tools, such as a saw or sander, look for a family of tools which can use the same battery packs. The brand you pick should also offer just the bare tool without a battery. Since the battery is a major part of a cordless tool’s cost, you can save money with each additional tool you get.

• Some drill models come with a handle you can attach to the side of the drill which provides extra stability, especially when the torque forces are high.

• A built-in LED worklight is handy for working in poorly-lit conditions.

• Variable-torque control is helpful for adapting to different size screws or work material.

• A drill with a battery charge indicator lets you monitor the remaining power.

• A “smart” battery charger can recharge a battery in 60 minutes or less compared to several hours for a regular charger.

Like any tool, cordless drills have their limitations. If you need maximum power, there’s no cordless substitute for a corded drill. But for typical homeowner projects and most professional work, they can be ideal.

There are currently 89 refurbished cordless drills and drill-drivers available on RefurbX.com.