Each generation of professional cordless portable power tools moves closer to matching the performance (including power, precision, and speed) and the range of features of comparable corded power tools. For electricians working in areas lacking convenient outlets for standing on or even reaching from ladders where the tangle and straggle of extension cords could be hazardous, battery-operated portable tools provide convenience and easy mobility. And because they require less set-up time, they also make shorter shrift of a day’s work when performing repetitive tasks such as installing switches or receptacles or when working through a punch list of items that require power tools at numerous locations on a project. To ensure continuity of production throughout the day, work with at least two battery packs, so you have backup to switch to, as needed.

Electricians should take several precautions when using battery-operated portable tools.

When pairing a battery pack to a tool, use only a pack designated to work with it. Ditto, when using a charger. A bad match could lead to a bursting battery or risk of fire. Set up the charger on a flat surface in a dry location, away from flammable materials. Never recharge a battery pack if the case is at all cracked.

To avoid accidental startup, verify that the trigger switch is locked before inserting the battery pack. (Likewise, make sure the safety switch is locked during any transport, even within locations on the job, and, for double precaution, keep fingers away from the switch or trigger during toting.) On a saw, it is good practice to remove the battery before making any adjustments to the shoe, if there is one, or to the blade, or before performing any other adjustments.

When not using a battery-operated tool, remove the battery and store it away from nails, screws, coins, keys, paper clips, and other small metal items that could inadvertently make a connection between the two battery terminals, causing sparks, burns, or a fire.

User-friendly features found, individually or together, in many portable cordless tools include soft-grip handles that enable users to sustain a solid hold on the tool and control it more easily, and in some tools such as a hammerdrill, a side handle that keeps the tool steady and reduces vibration. Both these attributes reduce operator fatigue during long work sessions. Also worthwhile in some types of tools: a counter-balance mechanism that rotates in the opposite direction of the blade or bit, dampening vibration at the handle, and keyless chucks, for quick, one-handed bit changes.

Battery packs for cordless tools are commonly 9.6, 12, 14.4, 18, or 24 volts. Tools that run on 36-volt batteries are also available. The length of time that cordless tools run between charges is dependent upon a number of factors. These include the voltage and amp hours (Ah) of a battery pack (up through 2.6 Ah for the tried-and-true nickel cadmium batteries found most often on tools in this country, and 3.0 Ah for nickel metal hydride batteries, which are newer and making inroads among manufacturers in the United States). Whatever the chemical composition of the batteries in the pack, the higher the amp hours the longer the run time between charges, but the fewer times the battery pack can be recharged. Also relevant to run time is the ambient temperature at which the battery pack is used and stored. Temperature extremes can destroy the batteries.

Tools described below are representative of manufacturer offerings. Many of these companies offer multiple tools within a category, in various voltages, and may offer the same tool either as a single unit or in a kit with a second (or more) types of cordless portable tool, with batteries (either Ni-MH or Ni-Cad) and a charger serving all tools contained within. (Some manufacturers also offer optional vehicle chargers that draw power from a vehicle’s cigarette lighter.)

When buying a kit of multiple tools that use the same battery pack, consider whether you want that capacity in multiple tools. You may end up using one of those tools in a higher-amp platform and in a heft that is larger than necessary for the given application. But the convenience of using one charger for more than one tool and the ease of interchangeability of battery packs (and the possible cost savings, overall) may override that consideration.

Milwaukee Electric Tool Corporation Sawzall The Hatchet 6514-21 18-volt, 2.4 amp-hrs. cordless reciprocating saw, sporting a ¾-inch stroke length and 0 to 2,700 strokes per minute (SPM) with a variable-speed switch, offers versatility to accommodate cramped workspaces and other restrictions. The compact tool features orbital action for aggressive wood cutting, including trimming and notching of studs, joists, and wooden planks; and straight action for cutting conduit and metal hangers. A six-position pivoting handle allows users to navigate in tight spaces. For example, when fully pivoted, the unit measures a compact 13 inches from the back of the handle to the front of the shoe, enabling an electrician to fit it easily between joists and studs.

Operators can also adjust the pivoting shoe forward or backward into any of six positions, to maximize length of blade use when applications benefit or to minimize blade exposure where there is little room for blade clearance.

Offering additional flexibility, the battery pack can be inserted facing toward the front for working in restricted spaces or from the rear for optimum weight distribution and balance.

The unit, which has a soft-grip handle pad and a counter-balanced mechanism that reduces vibration, accepts ½-inch shank universal blades that can be used face up or face down. A steel keyless blade clamp with spring-loaded collar facilitates fast blade changing.

Designed to withstand a 6-foot drop to concrete in any orientation, the saw comes in an impact-resistant carrying case.

Featuring an electropneumatic hammering mechanism, the HILTI 36-volt TE 6-A Cordless battery-powered Rotary Hammer Drill is well suited for drilling anchor- and through-holes in concrete, stone, and masonry, using the TE-C chuck with bits ranging in diameter from 3/16 to 5/8 inch. The tool also drills into wood, plastic, and steel with key-type and keyless chucks and wood bits up to ¾-inch diameter, high-speed steel drill bits or hole saws from 1 to 4 inches and 5/16 inch.

Changing chucks does not require any tools. For safety and chuck preservation, the hammering action is de-activated automatically when a key- or keyless-type chuck is fitted for drilling without hammering.

The side handle is adjustable and can be clamped in any position. The depth gauge, attached to the side handle, enables users to preset the drilling depth of the hole. This flexibility, according to the company, can result in more holes drilled per battery charge because there is no battery power wasted by drilling any deeper than necessary.

The TE 6-A uses the HILTI BD 6-86 battery, which is equipped with a deep discharge prevention device that avoids damage to the cells caused by excessively deep discharge. It also protects the entire system when subjected to extreme loads that stall the spindle.

Panasonic Home and Commercial Product Company’s new cordless combination drill/driver/impact driver model EY6535NQKW, which runs on a 15.6V 3.0Ah Ni-MH battery, features a dual-mode switching gear system that transforms a drill and driver to an impact driver. Well-suited to heavy-duty fastening jobs, the unit, which has an electronic brake and an 18-stage clutch, delivers up to 1,100 inch-pounds, at 3,300 impacts per minute.

For use as a drill driver, electricians snap on a ½-inch keyless chuck for high-speed drilling (0 to 650 revolutions per minute [RPM]) in wood and metal, generating up to 286 inch-pounds. A one-touch release allows for easy chuck removal. The ¼-inch hex quick-change chuck attachment facilitates convenient screw driving of shorter and smaller diameter screws. In impact mode, the tool is capable of high speed (0 to 2,200 RPM), heavy-duty fastening into metal, wood, and concrete. The ½-inch square drive with hex sockets are useful for fastening lag bolts, carriage bolts, and concrete anchors.

Featuring a sure-grip surface and precision balance, the compact unit is ergonomically designed to help combat user fatigue for prolonged use, said the company. The kit comes with two 3.0Ah Ni-MH battery packs, 45-minute universal charger (7.2v-24v Ni-MH or Ni-Cad), ½-inch attachable keyless chuck, ¼-inch hex quick-change chuck, and high-impact plastic carrying case.

Suitable for cutting plywood for electric panel installations, the BOSCH Power Tools 1660K 24-volt cordless circular saw drives an ultra-thin kerf blade up to 3,600 RPM. The slim blade facilitates smoother cuts by reducing drag and friction and extending battery life (up to 30 percent more run time, according to the company). The foot bevels up to 50 degrees for versatility of angle cuts. Maximum depths of cut range from 11/12 inches at 50 degrees to 21/8 inches at 90 degrees.

Built around a large, 60 mm open-frame motor, the 6½-inch saw features all ball and roller bearings, rear depth adjustment for one-handed depth-of-cut settings, and a dust collection port for dust and chip extraction when connected to an (optional) vacuum hose attached to a shop vacuum cleaner. The tool sports an ergonomic soft-grip handle, on-tool blade wrench storage, spindle lock, rip fence, and an adjustable line of cut indicator that allows the user to match depth of cut to the material. The saw comes in a kit with two Ni-Cad batteries, a one-hour charger that can charge BOSCH Power Tools batteries of any voltage, an 18-tooth carbide-tipped blade, and a tool case. An optional 15-minute charger is available.

DeWALT Industrial Tool Co., DW988K-2 is an 18V drill/driver with hammerdrill mode. Sporting a three-speed, all-metal transmission for added durability, the tool has a maximum torque of 450 inch-pounds. It offers variable-speed ranges with a maximum no-load speed up to 450, 1,450, and 2,000 RPM. The tool features a keyless chuck with a single rotating sleeve for one-handed operation of the chuck. In hammerdrill mode, in third gear, the unit boasts a maximum of 34,000 blows per minute (BPM), which provides 33 percent faster hammerdrilling compared to the company’s previous two-speed model, according to the company. The tool, with a T-style handle, anti-slip grip, and a 360-degree side handle, has a ½-inch heavy-duty ratcheting chuck lock and carbide jaws for tighter bit grip, to help preclude slippage. The kit includes a one-hour charger, two Ni-Cad extended run batteries, a double-ended screwdriver bit, and a heavy-duty kit box.

Makita USA’s 12V ½-inch Cordless Hammer Driver-Drill Model 8413DWDE features three mode settings for drilling, fastening, and hammer drilling. Designed to drill into masonry and concrete, and drill and drive into steel and wood, the tool sports a three-action mode collar that is independent from the clutch ring for quick switching from hammer drilling to driver. Sporting 16 torque settings, the 5.1-pound tool delivers a maximum torque of 280 inch-pounds and offers two-speed gear selection with variable speed in each range (0 to 400 RPM and 0 to 6,000 BPM or 0 to 1,300 RPM and 0 to 19,500 BPM). Drilling capacity is 19,500 BPM. A side handle rotates 360 degrees around the drill, for added support. Other features include an ergonomic rubber grip, easily accessible carbon brushes, and a single-sleeve keyless chuck. The tool also comes with two 2.6 Ah Ni-MH batteries. EC

THE FELDMANS provide Web content for companies and write for magazines, trade associations, building product manufacturers, and other companies on a broad range of topics. They can be reached at wfeldman@att.net or (914) 238-6272.