7 Things to Consider When Buying a Circular Saw

Close up detail of circular saw
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A portable circular saw (along with a cordless power drill) is one of the must-have tools for the DIYers home workshop. Buy a good circular saw now and you can expect to still be using it in 10 or 20 years. Here are seven things to keep in mind when you shop for your circular saw.

Sidewinder circular saw
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Mechanical Style

Circular saws have long been available in two styles: sidewinders and worm-drive. Sidewinders are the most recognizable style to most of us. The handle is set higher over the blade, and the blade has traditionally been located on the right side of the D-shaped handle, although left-handed saws are increasingly available. They are lighter and less expensive than worm drives, and the blade, which is driven directly by the motor spindle, spins faster than on worm-drive saws. A good sidewinder is the best choice for the home workshop since it is light and maneuverable.

Worm-drive saws are short and long, with the handle positioned behind the blade. The blade is located on the left, making it visible to right-handed users. They tend to be heavier, since they require a gear system to convert the motor action into blade spin, and they have more torque than sidewinders. Worm-drives are preferred by some construction pros for heavy-duty work.

Corded vs. Cordless

As is true of most power tools, circular saws now come in both corded plug-in models and cordless models powered by batteries. Until recently, corded models were far better for sustained, heavy-duty cutting, but recent innovations in battery technology have reduced the performance gap between corded and cordless models. Still, a DIYer who owns only one circular saw will likely want a plug-in corded model, which will offer more sustained power. But for DIYers who can afford two saws, adding a cordless saw will let you work where there is no plug-in outlet available.

Many tool manufacturers now offer sets of power tools that use the same batteries, and if you already own several tools by one manufacturer, adding a cordless circular saw that uses the same batteries is an affordable option.

Power Rating

For corded circular saws, the power rating is generally expressed in amperage. Today, 15-amp saws are the standard; 10- or 12-amp saws are appropriate only for infrequent use. The price difference just isn't that significant for a purchase you can expect to use for many years. The higher the amperage, the more cutting power the saw will have.

Cordless, battery-powered circulars are typically rated by the voltage of their batteries. Virtually all cordless saws now use lithium-ion battery systems. There are many 18-volt saws available, but there are also more powerful 20-volt cordless saws offered. As well as voltage, an amp-hour rating will also be listed, which indicates how long you can use the saw before the battery dies. The amp-hour ratings range from about 5 hours to 9 hours.

Blade Size

Circular saws are categorized by the diameter of the blade they take. The most common and useful size for DIYers is 7 and 1/4 inches. Saws this size will cut through material more than 3-inches thick, and they also offer the widest variety of blade choices for cutting substances other than wood. In the general-use category, there are also 6 1/2-inch and 8 1/4-inch saws, for lighter-duty and heavier-duty use.

Much smaller specialty trim saws are also available, with blades only about 4 1/4 or 4 1/2 inches in diameter. These tools are used mostly for cutting paneling and other thin materials, but some can also cut dimension lumber.

Ergonomics

From a distance, every sidewinder circular saw looks pretty much the same, except for the color. Up close, though, they can feel much different in the hand and when you use them. The only way to experience that difference is to head to your local tool supplier and test them for yourself. Does the handle fit your hand? Does the saw feel well balanced and the right weight for you? Are you comfortable with the visibility of the blade and the adjustment components?

A well-shaped handle and good balance can go a long way toward making a saw more comfortable and efficient to use, so don't overlook these features when choosing a circular saw.

Additional Features

Most any circular saw with sufficient power and fitted with a good blade will do adequate cutting, but for long-term satisfaction, you may want to look for these features:

  • Saw foot made from cast magnesium rather than pressed steel
  • Power brake to stop the blade quickly
  • Preset bevel stops on the saw foot (22 1/2 and 45 degrees are most useful)
  • A spindle lock to simplify changing blades
  • Built-in work lights to illuminate the workpiece
  • Laser guideline to help keep saw aligned

Blades

Most new saws come with a carbide-tipped all-purpose wood-cutting blade. If the saw comes equipped with a simple high-speed stainless steel blade, it's low price might not be such a bargain; you probably will want to replace it with a more expensive carbide-tipped blade almost immediately.

A good carbide-tipped blade might be the only blade you ever need, but there are many other types of blades available for special purposes. You can buy blades for cutting wood, metal, tile, and concrete. If you plan to do a lot of work requiring clean cuts, consider buying a blade with a higher number of teeth. Changing blades takes just a few moments.