When I began working in the building trades some thirty-plus years ago, carpentry tools fell into two categories: basic hand tools and simple electric power tools. I didn't start working with cordless tools until the mid-80s, when I bought my first 9.6-volt, 3 3/8-inch blade cordless saw–more of a toy than a tool. Today, however, cordless technology seems to be the fastest growing segment of the construction tool market, and cordless saws have come a long way in terms of technology, power, and performance. I was eager to test the newest models on my jobsites, and I am happy to say that many of these saws finally can be considered power tools.
I tested 11 saws powered by five different voltages. The 18-volt saws were the Bosch 1664K, Hitachi C18DL, Makita BSS610, Metabo KSAP18, and Panasonic EY3551GQ. Tools in their own voltage class were the 20-volt Craftsman 320.17199, 24-volt Ridgid R885, and 28-volt Milwaukee 0730-22. The remaining tools were all 36-volt: the Bosch 1671K, DeWalt DC300K, and Hilti WSC7.25-A36.
Out of the Box
What You Get. Most of these tools come in kit form with a charger and one or two batteries, but some must be purchased differently. To compare prices equally, look carefully at what comes with the tool. With some single battery costs approaching $200, what you don't get also can be important to know. The tools sold in a full kit, with two batteries, a charger, and a case, are the Craftsman, Makita, Metabo, and Milwaukee. Tools sold in a kit with only one battery are both Bosch tools, the DeWalt, Hilti, and Panasonic. The Hitachi saw is available only in a multitool combo kit, and the Ridgid must be purchased in a combo kit or all alone, with batteries and chargers sold separately. Several also are available as tool-only models, which allows you to economize by not buying duplicate batteries and chargers if you have invested in their systems already. These include the Bosch tools, Craftsman, Hilti, Makita, and Milwaukee saws. And, of course, most of these tools are available as part of a combo kit.
Design Specifics. Most of these saws use the latest lithium-ion (LI) battery technology, except for the 18-volt Bosch with its nicad batteries and the Panasonic with its Nickel Metal Hydride (NiMH) batteries. Three of the models with LI batteries have flexible fuel capability; the Hitachi and Metabo tools can use nicad or NiMH batteries of the same voltage, and the Ridgid can use 24-volt LI or 18-volt nicad battery packs. The 36-volt Bosch also can use a smaller battery with a reduced amp-hour rating.
Eight of the saws have 6 1/2-inch saw blades, the standard of cordless circ saws. Only the Craftsman, DeWalt, and Hilti use 7 1/4-inch blades more commonly found on corded saws. Nine saws have the blade on the left side, the Hilti and Ridgid have theirs on the right. This is a curious trend; the vast majority of corded saws with similar "sidewinder" motors are blade-right, but the norm among these cordless saws is opposite.
The lightest saws weigh about 7 1/2 pounds, while the heaviest saw tips the scale at close to 12 1/2 pounds. This weight difference is considerable and showed up in both the power and feel evaluations. The range of tools in this category is broad in voltages, sizes, and weights. But since they are all made to cut the same materials, I tested them side by side under the same conditions. I didn't handicap the smaller tools. Rather, I noted their performance along with their comfort and maneuverability virtues.
Field Testing
With the exception of the controlled battery run-out and speed-of-cut tests performed in the shop, I evaluated these tools in the field, subjecting them to the rigors of everyday building use. I put these saws to work during a recent framing job, where we cut studs, ripped plywood, and fitted rafters. I used the saws in the same manner that I would use a corded saw–I didn't try to force my cuts, nor did I baby the feed speed of these tools. During these uses, the saws began to distinguish themselves by application. Some of them are best suited for trim work, and others have enough guts for framing jobs.
For cutting functionality, any of these tools will cut lumber and plywood and some will do virtually anything that you would expect of a corded circular saw, but generally not as fast and definitely for not as long. And when the going gets tough, the weaker saws stall out often.
As for replacing a corded saw, there was no question that the Hilti saw was the workhorse of the group, and no coincidence that it is the most massive. Its large battery makes it bulkier and even heavier than many corded saws. On a typical day of framing, this tool would make it through on two charges of its battery. With an additional battery, this saw has the ability to work on a remote jobsite all day without assistance from the power grid or a generator. None of the other saws gave me that confidence; most required a battery change every two to three hours on the job.
Shop Testing
I performed three controlled shop tests,which consisted of more than 800 feet of cross-cutting and nearly 2,300 cuts. I tested battery runtime by cross-cutting 2x4s with a freshly charged battery and a new blade in each saw, and measured in cuts per charge. Then I evaluated relative power of each tool, again with new blades and fresh batteries, by cross-cutting the same long 2x10 more than a dozen times with each saw and averaging the timed results in seconds. I performed a high-demand test by timing the cuts through a 1 3/4-inch by 12-inch piece of laminated strand lumber (an OSB board), which not all of the saws could do. Those with no posted results took more than a dozen tries each to make it through the LSL once without the motor or battery shutting down, and are not suitable for such heavy cuts.
When a rough measure of efficiency is figured by comparing the number of cuts per volt, it is interesting to note that, without exception, the higher amp-hour batteries achieve the higher ratios.
With the newer LI battery technol-ogy, I noticed that the tools worked at full strength until there was insufficient power to operate at capacity. When they reached this point, the saws simply stopped working. Other battery chemistries tend to keep working slower until the power level is too low to operate the tool under load.
I was able to test all of the saws, except one, using the same 24-tooth, thin-kerf framing blades. The exception was the Panasonic, which requires a blade with a special 20-millimeter arbor hole, which is larger than a standard 5/8-inch hole and, therefore, cannot be adapted. The Panasonic saw was tested with its supplied 48-tooth, thin-kerf blade. The manufacturer's stated reason for the odd size is to make sure that people use proper (read: proprietary) thin-kerf blades, but I found it to be unnecessary hand-holding that makes it impractical to find replacement blades.
Feel
Sometimes it's the subtle things that make one tool more attractive than another. In the case of these saws, this meant evaluating weight and balance, grip and trigger comfort, and general ease of operation–what I like to call user friendliness.
Beyond the specific weight, the balance of a tool is something a user really notices while cutting. Saws I found particularly well balanced include the aforementioned Bosch, the Hitachi, Makita, Milwaukee, and Ridgid. Poorly balanced tools include the Craftsman and DeWalt.
If a tool you use frequently isn't comfortable to grasp and operate, you probably won't enjoy using it. Saws with a handle and trigger combination that feel good in your hand can motivate you enough to pick up one saw instead of another. Again, these include the 36-volt Bosch, Hitachi, Makita, Milwaukee, and Ridgid. Before you can run a cordless saw, you must depress a safety trigger with your thumb. A common characteristic of these five was the ability to grasp the tool and operate the two-stage trigger switches without contorting your hand. The DeWalt felt less comfortable to hold and operate with the plastic around its trigger digging into the user's finger. The 18-volt Bosch has a rear handle that is too fat to hold comfortably, and the Metabo suffers from a rear grip that is both too far forward and too high on the saw, which makes it uncomfortable to push across the work.
