What the best circular saw has
- Adequate cutting power. A saw should be able to stand up to a hefty piece of wood without bogging down. Professional framer Tim Uhler, writing for the Journal of Light Construction, says a 15-amp in-line saw -- worm drive or hypoid -- is best equipped to stand up to the densest types of lumber. In-line saws are typically geared to run at a lower speed than sidewinder saws, so like a cyclist going uphill in a low gear, their lower speed gives them more power on each push. However, most corded or cordless sidewinder saws can still handle tough wood; they'll just take longer to get through it.
- A snag-free blade guard. The blade guard is a crucial safety feature, but it can also be a major annoyance if it gets stuck and stops the saw in mid-cut. This is most likely to happen when you're cutting a compound angle or trimming a small piece off the end of a board. Uhler says this problem leads many professional contractors (who should know better) to pin back the blade guards on their saws, or even remove them completely. Since a safety feature can't protect you if it's disabled, it's crucial to choose a saw with a blade guard that retracts smoothly at all blade depths and all angles. Saws with a large protruding "lobe" at the leading edge of the blade guard tend to work best.
- Good safety features. These can include a spindle lock, which keeps the blade from moving while you switch blades, and a safety switch (sometimes called a "lockout switch") to prevent accidental starts. An electric blade brake, available on some models, stops the blade quickly when the trigger is released. Without this feature, you have to wait until the blade stops spinning before you can set down the saw.
- A sturdy base plate. A saw's base plate, or shoe, is one of the most commonly broken parts. Stainless steel base plates are the worst, as they can bend easily if the saw is dropped. Cast aluminum or cast magnesium base plates are better, but they can crack if dropped from a significant height. Fiber-reinforced plastic shoes are the toughest, provided they're thick enough to be stiff. In general, the best base plates are thick and heavily ribbed, with square edges.
- A stable connection between base plate and blade. Every circular saw's motor and handle assembly connects to the base plate at a pivot point, allowing you to adjust the depth of the cut or the bevel angle. On saws that place this pivot point in line with the blade guard, pushing down on the handle can tilt the motor, resulting in a bevel you didn't want. Saws with the pivot point in line with the rear handle tend to be more stable.
- Smooth bevel adjustment. If you plan to do a lot of framing work, particularly for roofs, a smooth bevel function is crucial. The bevel gauge should be easy to read, with clearly engraved markings in one-degree increments so you can dial in the exact angle you need. The base should also pivot smoothly when you adjust it. It's convenient to have bevel stops, or detents, at commonly used angles, such as 22.5 degrees and 45 degrees, but it should also be easy to override these detents and set the bevel to even bigger angles if you need to.
- Easy depth adjustment. To adjust the depth of your cut on a circular saw, you need to loosen a lever and move the base plate up or down. This is hard to do on a saw with inboard levers, which are tucked between the handle and the blade guard. Outboard levers, located to the left of the handle, let you keep one hand on the handle and use the other to adjust and lock the blade depth. Levers are also easier to grasp when they're thick and rounded or coated in rubber. The depth-setting bracket should slide smoothly without binding, and the depth scale should be clearly marked – ideally with engraved numbers rather than stickers that can wear off.
- Clear cut-line visibility. To make accurate cuts, you need a cut-line marker that's perfectly aligned with the kerf (cutting edge) of your blade, for both 90-degree and 45-degree cuts. The best indicators mark both sides of the kerf, so you can cut either to the right or the left of the line. However, it's not always possible to see your cut-line marker from all positions, so saws also have a window that provides a clear light of sight to the blade itself. On some saws, handles or guards can obstruct this window at maximum cutting depth, blocking your view of the blade.
- Useful extras. Some saws come with additional features that, while not crucial, are handy to have. For instance, experts particularly like saws with onboard storage for an Allen wrench, so the tool is conveniently available when you need to change the blade. Another nice feature is an LED work light that illuminates your cutting area, making it easier to follow your cut line even in dim light. And for cordless circular saws, a battery gauge is useful.
Know before you go
Check the weight and balance. Even the best-designed saw in the world won't work for you if it feels uncomfortable in your hands. Experts recommend going to a few different stores and trying out multiple saws, handling them just as you would during actual use, to get a good sense of how they feel. Make sure to test the saw in the positions you'll it in most often; the most comfortable handles for overhead work may not be best for long cuts across plywood. Also, if you work in a cold climate, you should also test the saw with gloves on to make sure there's enough space around the trigger for them.
Blade-left or blade-right? Most corded sidewinder circular saws have the blade mounted to the right of the motor, while cordless circular saws most often put it on the left. Each arrangement has its pros and cons. For a right-handed user, putting the blade on the right makes it harder to see, but it also shields your face from sawdust as you cut. Having the blade on the left gives you a clearer view but exposes you to more dust – and it also puts the weight of the saw on the "drop" side of the board, so you can't use the board to help stabilize the saw when making short cuts. For a lefty, of course, these advantages and disadvantages are reversed. It's up to you to figure out which configuration is more convenient for you.
For cordless saws, consider battery life. All the cordless saws in this report use lithium-ion batteries, rather than the heavier and faster-draining nickel-cadmium (NiCd) type. However, some manufacturers' batteries last longer than others, and some take longer to recharge once they're drained. In general, the more powerful a cordless saw is, the faster it will drain the battery. If you want your saw to go at least a few hours between charges, choose a battery with a higher capacity – at least 3 ampere-hours (Ah), and preferably 4 or 5.
Choose your accessories. One accessory many reviewers consider especially useful is a rafter hook, which lets you hang your saw from a joist, rafter, or sawhorse, ready to grab the next time you need it. Users also express a strong preference for larger carrying cases with storage for additional blades. Finally, most users recommend adding a rip fence – a metal bar that runs parallel to the blade to guide your cuts – if your saw doesn't come with one.
Value expectations: The dollars and cents of it
Even the best saw is only as good as its blade – and the standard blades that circular saws come equipped with vary widely in quality. The best manufacturers don't necessarily provide the best blades, either; even otherwise excellent saws often get a fair number of complaints from users about their low-quality blades. In several professional comparison tests of circular saws, the first thing the testers generally do is to replace the factory blades on all the saws with new, identical blades to level the playing field. The blade they typically choose is the Irwin Marathon blade (Est. $9), which includes such high-quality features as carbide teeth and a smooth silicone coating to slide through resinous materials. If you're already investing $100 or more in a circular saw, consider spending an extra few dollars on one of these blades to get the most out of your new tool.
IRWIN Tools MARATHON Carbide Corded Circular Saw Blade, 7 1/4-inch, 24T (24030)
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