Power to the people

April 18, 1997
Handheld power tools are shedding their cords and becoming more portable, as well as lighter and quieter

Millions of people rely on powered hand tools to make their lives easier. Among them are construction workers, woodworkers, homeowners, do-it-yourselfers, and assembly-line personnel, along with thousands of home-improvement contractors such as plumbers and electricians. And they all have different needs. Professionals want tools that stand up to worksite abuse with the newest in ease-of-use features, and price is often no object. Homeowners and hobbyists, on the other hand, might want a more versatile tool, one that handles several tasks well but isn’t optimized for any particular one. For these users, price is often paramount. Then there are those who want the best, with the latest and greatest in features and power, even though they will never fully utilize all the tool’s features or come close to pushing its performance envelope.

Tool manufacturers have responded with a seemingly bottomless toolbox of powered drills, grinders, sanders, saws, routers, and so on, all just a little bit different or designed for a specialized job. Black & Decker, for example, produces at least 20 models of handheld power drills, while DeWalt, a division of B&D devoted to manufacturing professional- grade tools, produces another 36 drill models.

To keep their customers satisfied, and attract new ones, manufacturers have been offering lower-cost tools with improved ergonomics and a wider range of features. One of the most popular of these new features is battery power, which gives users portability while working on the job or at home.

Battery-powered or cordless tools are one of the fastest-growing categories in power tools, with advances in rechargeable batteries spurring development. Battery packs have gone from 3.6-V systems to a new high with De- Walt’s 18-V line. This line features a drill/driver and saw, available in June, and two more drill/drivers available in August, all of which use an interchangeable XR battery pack. DeWalt designed these tools for professionals, especially electricians and plumbers who have never considered using cordless tools for the heavy-duty applications of their trades. For example, the 18-V drill can run a 7⁄8-in. ship auger through several 2 x 4 studs for wire or pipe installation — a job typically requiring a 1⁄2-in. corded drill. The 18-V cordless DeWalt saw runs up to 3,200 rpm and can cut 125 2 x 4s on a single charge. According to De- Walt, their 18-V XR battery pack provides 70% more run time than a standard 12-V battery.

Black & Decker uses a similar concept but with lower-voltage batteries in its VersaPak system, 20 different tools running on one or two 3.6-V VersaPak rechargeable batteries. Designed for DIYers rather than professionals, the batteries should provide enough power to complete relatively simple projects such as hanging blinds, assembling furniture, or building shelves. According to the manufacturer, the VersaPak screwdrivers will drive 200 #6 screws into 1-in. fir on a single charge. The systems come with a choice of rechargers which take between 4 and 18 hr, and each battery can withstand 300 full recharges. Since most batteries are not fully drained before being recharged, users should be able to recharge VersaPak batteries more than 300 times, according to B&D. These batteries, unlike those used in many camcorders, can also be fully recharged even if not completely drained.

Ryobi-America also designs and builds a large line of battery-powered tools and accessories. One of the most important accessories is the 1-hr “smart” recharger. Besides being able to fully recharge depleted batteries in 60 min, it detects hot batteries just taken from a tool. Most other rechargers won’t charge hot batteries. Ryobi’s charger puts hot batteries on a trickle charge until they cool, then switches to full-recharge mode. A circuit in the recharger identifies defective batteries, so users don’t short out the charger or mistakenly believe the charger is defective when the problem is a bad battery.

A drawback in the push for more power in portables is that as the battery voltages climb higher, so does their weight. “An 18-V battery pack can weigh 5.5 lb, which is probably too heavy to use all day, the number one complaint among users of cordless tools,” says Matt Nelson, marketing manager for Hitachi’s electric tools. “We’ve stayed with 12-V tools, but introduced a 2.0-A/hr battery, one of the first in this market. We also designed a belt pack that can hold two batteries and clips onto a user’s workbelt. A cord connects the batteries to the tool, letting workers roam the worksite without having to recharge or replace batteries. For commercial users, it gives them greater power and reduces weight. For example, Hitachi’s 12-V tool weighs only 3.2 lb, less than a 9.6-V tool with the battery pack attached.”

Still, there seems to be a drive among consumers for tools with more power. “But most people just don’t need it,” says Jeff Dils, director of design and development for Ryobi-America, a tool manufacturer based in South Carolina. “Cordless tools on the market now have more power than most people will ever use, but there are always those who will buy based on power ratings, and there are contractors who actually need more power in a portable tool.” His advice to DIYers shopping for cordless tools is to determine what you are going to use the tools for, and unless you’re going to drive lag bolts 8 hr a day, a 12 or 14.4-V system is as high as they should ever need to go. And 7.2 or 9.6-V tools should be enough for most people. “Consumers should really look for drills and other tools with twospeed gearboxes because that’s what gives tools the versatility for heavytorque applications as well as higher speeds for normal drilling,” he says.

Tool designers are also concerned with noise and dust, two constant companions when it comes to using power equipment. In the past, designers worried mostly about dust and grit working their way into the motor or the gears and bearings of the tool and wreaking havoc. Hitachi, for example, uses two dust seals and a copper bushing on the front end of its reciprocating saw to keep dust levels inside the housing at negligible levels. The copper bushing, which is longer than the length of the stroke on the saw’s shaft, keeps most of the dust out. “On some of our competitors’ saws, the stroke of the piston is longer than the seal,” notes Matt Nelson, Hitachi’s marketing manager for electric tools. “You can draw a pencil line on the shaft outside the seal, rotate the reciprocating mechanism, and the pencil mark ends up inside the seal, illustrating the fact that dust can do the same thing.”

Health and environmental concerns have pushed designers to not only keep dust out of the tool, but also out of the air, which has led to an array of imaginative dust-collection systems. These systems become much more critical when removing lead paint or working with masonry, which present potential health hazards. Companies are turning to vacuum bags, HEPA filters, high-efficiency particulate accumulators, and wet systems in which the water is used to turn the dust into a more manageable slurry. Some companies make tools with integral dust-extraction systems which rely on a user’s shop vacuum. DeWalt’s new DW621 router, for example, is the first router with such a system. Dust is pulled through the router and out the tool’s dust hose by a shop vacuum. This is an easier and more efficient methods of dust control than cumbersome add-on kits, according to De- Walt.

Noise is practically inevitable when cutting, sawing, hammering, or drilling, but manufacturers still try to reduce as much unwanted or objectionable sounds and vibrations as possible. De- Walt’s 18-V drill, for example, features a spring-loaded clutch-plate assembly. The spring forces the clutch plates apart at the point where a screw is set, eliminating clutch-plate noise called ratcheting. It also drives screws more efficiently and increases clutch life.

Hitachi’s new grinder, the G12SE, was also designed for reduced noise and vibration. One technique they used was to create an air funnel or channel inside the tool, which increased airflow overall by 40%. “Now, instead of air flowing in and around the motor armature, there are clearly defined pipelines directing air through the back of the grinder and out the front,” says Nelson. “By controlling the direction the air takes, we reduce vibrations and whistling, as well the load on the fan.”

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