Circular saw buying guide

A cordless saw leaves you unfettered by a power cord. Some of the latest perform far better than earlier models--at least until the battery runs down. But some are far less powerful and cut far more slowly. A weak saw can bog down on tough jobs such as thick hardwood. And a slow-cutting saw is frustrating when you have lots of wood to cut. Speed also affects safety. You're more likely to push a slow saw, dulling the blade quickly and overheating the motor, or making the saw jam or kick back.

That's why we think most serious do-it-yourselfers would be happier with a corded saw or even both corded and cordless versions. Expect to pay anywhere from about $100 to $150 for the best homeowner models.

Look for design points that make a saw easy to live with. These include good balance, a comfortable handle, a clearly visible blade and cutting guide, easy blade adjustment for depth and angle, and a handy on/off switch. Quality of construction can be harder to evaluate at the store, but it contributes to long, trouble-free performance. Look for a saw with durable roller or ball bearings, motor brushes that are accessible for servicing or replacement, and heavy-duty hardware.

All the saws are loud enough when cutting to warrant hearing protection. And all kick up a lot of chips and dust, so wear safety glasses or goggles. Also, a circular saw blade can't tell wood from fingers.

These are best choice for most people. Their electric motors range from 10 to 15 amps--typically, the more amps, the better. Most are designed with the motor perpendicular to the blade. Those we tested were as much as seven times as powerful and speedy as cordless models.

Also known as worm-drive or sidewinder saws, these corded models are popular with professional carpenters. These heavy-duty models use a gear drive to mount their motor parallel to the blade, making them longer and narrower. These saws tend to produce more twisting power, or torque, so the blade is less likely to bind in dense or thick wood. Indeed, you can feel the high-torque motor jump to life as soon as you press the on/off switch. But they're heavy and pricey, and their reduced blade speed makes sawing slower.

Cordless models typically range from 18 to 36 volts and are the only option where electric outlets aren't available. They're lighter and smaller than corded models, making them handy in confined areas. But while fine for occasional light work, they aren't for tough jobs. They usually have a smaller blade. And the harder they work, the faster they discharge; those we tested ran only 5 to 15 minutes on a full charge when we hooked them up to a dynamometer. Battery-powered models are also relatively expensive.

Most saws now come with a carbide-tipped blade, which cuts faster and lasts longer than a plain steel blade. Fortunately, you can replace steel blades with carbide-tipped versions. Be sure to match the number of teeth to the material you cut: A blade with two dozen large teeth cuts quickly, but it can splinter the wood, while one with 40 or more fine teeth gives a slower but cleaner cut. The thinner the blade--referred to as its kerf--the faster the cut and the less wasted wood.

This feature stops the blade quickly when you release the trigger, providing an extra margin of safety.

For right-handed users, a blade mounted to the left of the motor helps you to see the blade and your cutting mark without leaning over the saw. (Lefties may want to look for a saw with the opposite configuration.) A notch in the upper blade guard also helps you to see the blade; a wide notch is less likely to clog with sawdust.

A thick reinforced-steel or composite base is better than one made of thin, stamped steel.

A 9- or 10-foot cord may make an extension cord unnecessary. Even if you need an extension cord, the extra length of the saw cord helps keep the cord junction away from your work.

On some models, pressing a spindle lock button keeps the blade from turning, making it easier to change the blade. Without a blade lock, you have to hold the blade with a piece of wood or a gloved hand. Some models let you change blades without a wrench.

The safety interlock prevents accidental start-ups by requiring you to press a second switch to turn on the motor. Most corded saws and some cordless models have this interlock.

Some corded and cordless saws project a laser line to highlight where you want to cut. Though manufacturers tout this feature, it's only marginally useful. You still have to draw a line and keep a steady hand. And lasers are useless outdoors in bright sunlight.