I last tested cordless circular saws for TOOLS OF THE TRADE five years ago. The story back then was that the introduction of lithium-ion technology had helped battery-operated saws become more useful on the job site, but there were few standout tools in the 18-volt class. The higher voltage (28- and 36-volt) saws were the way to go when cutting framing material; the smaller tools seemed better-suited to trimwork and other light duties.

Fast-forward to today, and you'll find that the category as a whole has improved greatly. Except for our favorite 18-volt model in the last test (Makita BSS610), the saws tested are new designs.

All but one of the kits came with their brands' highest amp-hour (Ah) lithium-ion batteries. The Bosch shipped with 2.6-Ah batteries, but we tested it with 3.0-Ah batteries — because we tested the other tools with the best batteries available at that time. DeWalt makes two 18-volt saws; the more recent model takes slide packs, and the earlier model takes tower-style batteries. The earlier tool comes with a lithium-ion pack but can be used with the brand's very popular nicad batteries, so I tested it with both. Hilti's battery pack contains extra cells, so it's actually a 21.6-volt tool; I included it because it's the same size as an 18-volt model.

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All the tools in this test have 6½-inch blades, 50-degree maximum bevel angles, and electric blade brakes. Every manufacturer supplies its own blade, so to even the playing field I equipped every saw with an 18-tooth Irwin Marathon blade.

BLADE-LEFT DESIGN

With the exception of two standard-format sidewinder models (Porter-Cable and Ridgid), the saws I tested were blade-left models — a curious trait when you consider that corded sidewinders typically have blades on the right. This aspect of the saws makes them handle a lot differently than their corded counterparts and takes some getting used to. While gaining a clearer view of the blade, you also gain a face full of sawdust, at least in right-handed use. And the weight of the saw sits on the “drop” side of the material being cut, so it requires more careful balancing to make short or shave cuts without tilting the blade.

BASIC FEATURES

All the saws have a comfortable grip with rubber-coated rear handles; where they differ in comfort is in the operation of their trigger-lock safeties. Tools that require you to push inward on a release button (Bosch, Kobalt, Porter-Cable) feel clumsier to use than ones with release levers you push straight down on. A button requires you to move your thumb, which loosens your grip on the tool slightly, whereas pushing a lever down is part of a good gripping action.

Saw stability is important, too. On most circ saws, the connection between the motor and base is in line with the blade housing; pushing down on the handle tends to tilt the motor, binding the blade and robbing the tool of precious battery power. This is less likely to happen when the connection point is in line with the handle. Only the Hitachi has this configuration, though several other saws were just as stable (see spec boxes starting on page 32).

I liked some of the extras on these saws: Six models had battery fuel gauges and three had headlights. I was less impressed with the laser line pointer on the Porter-Cable. I have yet to find a good use for this gadget on handheld saws — other than pointing the saw straight at the DIY market.

PERFORMANCE FEATURES

Certain features — common to every saw — have a major impact on performance. Here are four that, depending on how well they work, can make the difference between a good saw and a great one.

Guard

The guard should operate smoothly at all blade depths and cutting angles; the shallower the blade is set, the better the guard usually works. Hang-ups that require holding the guard open with one hand are a nuisance, especially when you're using the saw with one hand and holding the material steady with the other.

The Makita saw has a built-in light that is activated when the trigger is depressed slightly; the Hitachi and Ridgid are similarly equipped.Contrasting colors and graduations set one degree apart make the quadrant on the saw at left easier to set and read than the quadrant on the more basic model at right.