The power drill is one of the most popular and versatile power tools. Thanks to a host of improvements in its design, today’s drills have many more functions than just drilling holes. Most have variable speed and reverse, making them convenient for driving and removing screws, nuts, and bolts, as well as for drilling, sanding, and stirring paint. A keyless chuck makes it easy to swap bits or quickly convert a drill into a grinder, sander, or paint mixer. Newer models allow you to adjust the drill’s clutch for drilling or for driving into various materials, so the clutch will automatically disengage before screw heads strip or sink too far into the material.
Drills are commonly available in 1/4-inch, 3/8-inch, and 1/2-inch sizes. The size refers to the maximum diameter of the bits and other accessories that the drill will accept. A 3/8-inch drill is standard for carpentry projects because it accepts a wide variety of bits and accessories and runs at a higher speed than 1/2-inch models.
Cordless technology has made drills more portable than ever. But it’s important to understand the strengths of corded and cordless designs before deciding which one you should own. Most cordless drills operate at slower speeds and with less torque than corded models. Yet, cordless models are convenient because they allow up to several hours of operation between charges and eliminate the need for extension cords. Top-of-the-line cordless drills generate about 1,200 rpm. Corded drills weigh significantly less because they don’t require battery packs, and some operate at more than 2,000 rpm. For most jobs, a cordless drill’s slower speed is not a problem, but as the battery wears down, drilling becomes difficult and more of a strain on the motor. Spare battery packs can offset this problem. If you own both types of drills, keep your corded model on hand as a backup.
Shopping for Drills
When shopping for a drill, remember that the most powerful tool is not necessarily the best one for the job. This is especially true of cordless drills, because higher voltage ratings usually require heavier batteries. A more powerful cordless model is useful for heavyduty drilling, when extra power will allow you to drill holes in thick timbers or masonry more quickly and easily. For driving screws and for light-duty drilling, a medium-voltage cordless model or a corded drill is a better choice. A drill in the 12- to 14.4-volt range is usually sufficient for most tasks. Try out several drills so you can compare the feel of the tools under load.
You’ll also appreciate having two battery packs to minimize waiting for recharging. Most good-quality cordless drills come with one-hour chargers.
Corded drills are still widely available because they can generate lots of torque and operate at speeds of 2,000 rpm or more. If you want a fast, powerful, lightweight drill, a corded drill may be the right tool for you.
A hammer drill combines the rotary motion of a conventional drill with the impact action of a hammer. It can drill holes in masonry much faster than a regular drill. Hammer drills can also be set for rotary motion only, making them useful for general drilling applications.