By R. Craig Lord

Publication Date: March/April 2002

Rolling a 100-foot cord out of the truck isn't cutting-in a roof vent; it's getting ready to cut-in a roof vent. Pulling up to the site with a cordless recip saw means we're on the roof faster. However, no matter how convenient and potentially fast they are, cordless tools need enough power and endurance to go the distance or they eat up the time they're made to save.

Test Criteria

For this test, I circulated 12 new cordless recip saws among my carpentry crews. I also loaned them to some plumbers and electricians to see how the tools stacked up and where they worked best. We tested Makita's 14.4-volt JR140DWA; an 18-volt group consisting of the Bosch 1644K, Craftsman 27129, DeWalt DW938K, Makita JR180DWD, Milwaukee 6514-21 (The Hatchet), Milwaukee 6515-27, and Ryobi RJC180; the 19.2-volt Porter-Cable 837; and 24-volt tools including the Bosch 1645K, DeWalt DW008K, and Hitachi CR24DV.

In the field we used the saws on a variety of remodeling applications, from a kitchen replacement to full-on demo work. We cut copper pipe, plaster walls and lath, wallboard, studs, and metal. We quickly found cordless recip saws are best used on out-of-the-way and hard-to-reach jobs, so we climbed onto roofs and dove into crawl spaces to see how they liked life in the boonies.

Back in our shop we timed each saw's cutting speed through doubled-up 2x4 framing. We also graded the tools on plunge cuts through a mocked-up asphalt/fiberglass shingle roof over plywood. And -- perhaps most importantly -- we worked each battery from a full charge until the saw stopped cutting by slicing a doubled-up 2x10 like sandwich meat. After performing these controlled tests, we calculated each saw's baseline working time on a single charge, which gave us a pretty clear idea of battery endurance and work time between charges.

While unpacking the saws we noticed that some tools only ship with one battery pack. We made it our first priority to find out how long the saws would work before recharging. We evaluated battery power, charge times, and adjustments, and where these tools would fit on our jobsites.

Field Operation

. Cordless tools aren't much good to you or your crew if the batteries can't keep pace with the work. If you find yourself reaching for that charger too often, you're probably better off plugging in. That's what we found on our big demo job. It needed big power, and the batteries in this group couldn't keep pace with the amount of house we had to take down. That kind of juice still needs to come through the power cord.

Considering these batteries will run down no matter what you're doing, we like the fact that the Bosch, DeWalt, and Craftsman saws come standard with two batteries. That keeps you moving. If you want a second battery for any of the other tools in this test, you'll have to purchase one or use batteries you already own from the same brand and voltage platform.

It's convenient and handy to be able to exchange batteries among your tools, but I feel you shouldn't have to make a secondary purchase in order to work all day. In other words, sell me a cordless tool with all the batteries I need. I also don't want to have to raid my drill box for a recip saw battery.

Run Time. Obviously, real-time run time is based on what you're doing. For instance, you can cut a mile of PVC for every foot of 4-by LVL. In our work we see plenty of solid-sawn headers and 2-by material, so we evaluated the saws' battery longevity for our jobs by clicking a stopwatch and slicing a doubled-up 2x10 to ribbons in the shop without a rest.

Porter-Cable, Hitachi, and Makita advise users to pull the batteries from their tools and charge them as soon as the saws begin to under-perform. We did that for all the tools we tested. Over-draining battery cells generates extra heat, which kills batteries fast. Pulling a battery at the right time maximizes its life.

If you do stick a "hot" battery in the charger (which generates heat to charge the battery in the case of NiCad packs), you're not doing any more damage. A charger senses battery temperature and trickle-charges the battery until it cools enough to take a full charge. This lengthens the charge time, but it's better than frying your power packs, especially when you consider how much a new one costs.

Milwaukee makes big run time claims on its batteries and the Hatchet's performance definitely backed up those claims. With 8 minutes and 40 seconds of non-stop go-juice, it cut longer than any saw we tested. Next came Bosch's 24-volt model at 6 minutes, which edged out Hitachi's saw by 15 seconds. The 18-volt DeWalt and Makita tools each put in 5 minutes and 30 seconds of non-stop work. That translates to about 5 to 7 complete cuts.

Power. Cutting speed is just as important as battery juice. At 2,900 strokes per minute (spm), the 24-volt DeWalt saw turned in the fastest cut time (9 seconds) in the doubled-up 2x4 test. Bosch's 24-volt saw operates a little slower (2,300 spm), but gobbled up the wood in 15 seconds for a second-place finish. The Milwaukee 6515-27 and the 18-volt DeWalt saw cut the framing in 22 and 23 seconds, respectively. The Hitachi took 31 seconds and the Craftsman came in at 25 seconds. The Ryobi saw took 59 seconds.

Interestingly, the inline Milwaukee saw (model 6515-27) was 2 seconds faster in this test than the company's new Hatchet saw (model 6514-21). The only cordless recip saw with orbital action, the Hatchet made it through the doubled-up 2x4s in 24 seconds.

We compared these results to those of the corded recip saws we tested for the May/June 2001 issue. Only the 24-volt DeWalt DW008K and Bosch 1645K, and the 14.4-volt Makita JR140DWA achieved cut speeds close to their corded counterparts. As detailed in the spec boxes, the other cordless tool cut times were much slower.

Capacity. These saws work best on light-duty jobs in close quarters or places hard to reach with a cord. We especially like them for cutting-in plumbing, roof vents, and for hogging-out copper and PVC lines. All the saws performed well in these situations and we didn't have to drag a cord into a crawl space or up a ladder.

We didn't have 12 roof vents to cut out in one day, so we mocked-up a fiberglass shingle-over-plywood roof section to test the saws' plunge-cutting ability. Each model plunged relatively easily, stayed on the cut line, and had enough power to cut the hole. However, we noticed that the lighter cordless tools vibrated more than their corded cousins. There's less mass in the tool bodies to counter the blade action, so they tend to shake around a bit. Since you'll run out of battery juice or work before you get seriously tired, the extra vibration is no big deal. For a recip saw, I'd choose lighter weight over less vibration anyway.

One of the most innovative tools in the group, Milwaukee's Hatchet, has a handle that articulates into six operating positions. The tool really came in handy in tight spots between studs, under sinks, and in crawl spaces. To a lesser degree, the uniquely shaped Porter-Cable tool squeezed into some tight spots, too. Both DeWalt models are quick cutters and, because they're both lightweight, they're easy to handle in tight spots or for repetitive cuts like those our plumbers and electricians make.

Since plumbers and electricians don't usually do the kind of major demo work we do, the cordless saws' batteries gave them plenty of power for tasks like cutting through PVC and drywall and notching studs.

Features

Adjustments. Some of the recent engineering improvements we've seen on corded recip saws now appear on cordless models, too. Tool-less blade changes and tool-less shoe adjustments are two of the most important innovations. We liked the blade-change features on the Makita, Milwaukee, and Bosch saws the best. They all have equally easy-to-use and durable hardware, making blade changes a snap. You can get your fingers in there and the blade-release action is manageable.

The tool-less, lever-action blade-change mechanism on both Bosch models is an improvement over the company's corded version. DeWalt's plastic lever system is easy to operate, but we have to wonder about its long-term durability.

Adjustable shoes are good for controlling cut depth, which keeps the blade from plunging too deep and wearing out prematurely. In addition, adjusting the cut depth exposes fresh teeth at different spots so you can get the most use from each blade. The Bosch, Milwaukee, and Makita saws have the best shoe adjustments. Bosch's push-button device is easy to operate. Makita's shoe adjusts with a flip of a lever, and Milwaukee's saw has a patented pull-out lever.

Cutting options. The cutting options available on corded recip saws are notably absent from their cordless cousins. Milwaukee's Hatchet is the only cordless saw with an orbital cutting option, but it doesn't seem to help it cut any faster.

Just two of the other saws we tested have cutting options. DeWalt's DW008K model has separate speed settings for wood and metal. Bosch's 1645K and 1644K models have 3/4- and 1-1/4-inch stroke options for cutting metal. This doesn't change the blade speed, but shortens the stroke for efficient metal cutting.

Favorites

We regard these saws as specialty tools because they're not quite ready to replace corded reciprocating saws for the big-deal demo work we encounter regularly. However, they're good for doing difficult cuts in difficult locations without trailing knotted-up extension cords behind you. We even used them to trim tree branches so we could set a new window.

Because they're lightweight, versatile, and fast, we like the 18-volt Milwaukee Hatchet and DeWalt DW938K for work in really awkward, cramped places. However, these saws don't have the cut speed or power to match the 24-volters.

Our overall favorite saw is the 24-volt Bosch 1645K. It's as close as you can get to a corded tool's cut speed, power, and jobsite utility and it comes with two batteries. The 24-volt DeWalt DW008K is next, followed by the Milwaukee Hatchet, DeWalt DW938K, Porter-Cable 837, Bosch 1644K, Makita JR140DWA, Hitachi CR24DV, Makita JR180DWD, Milwaukee 6515-27, Craftsman 27129 and Ryobi RJC180.

A note about the Makita JR140DWA saw: It performed well, even though it's only a 14.4-volt tool, but the small battery didn't last long enough for our work.

R. Craig Lordis a custom builder and remodeler. He resides in Moorestown, N.J.

Hanley-Wood's Tools of the Trade has arranged with the companies in this test to donate their tools to Habitat for Humanity

Too New to Test: Makita BJR240SH

Volts: 24; Weight: 9.7 lbs.; Amp-hours: 1.7; Spm: 0-2,300/0-2,700; Stroke length: 1-1/4 in.; Tool-less blade change: Yes; Street price: $479 Makita USA; 800-462-5482; www.makitatools.com.

Comments: Makita adds a new 24-volt tool to its MakStar system with this model. It ships with a 1.7 amp-hour battery, but you can order a more powerful 3-amp-hour battery as an accessory. Makita has taken its new tool-less blade change mechanism to the next level, having the only one-handed device out there, the company claims. The saw has separate speeds for metal and wood. The tool hit the market in February 2002.

This article is reprinted courtesy of Tools of the Trade