Cordless Drill Drivers
Of all the "must have" tools out there for everyone from the do-it-yourself homeowner to the professional craftsman, the cordless drill tops the list. Over the past decade better technology has produced tougher tools with longer battery life and very acceptable torque ratings, all at prices to fit just about every budget.
"The thing about drill drivers is they are the one crossover product that basically touches all aspects of construction," says Randall Coe, director of product marketing for Bosch Power Tools. "You see them in residential, remodeling and commercial construction, because they make holes, they fasten and they have no cord. They are extremely versatile tools."
The early cordless drills were great for lightweight jobs like driving a few screws, but they could not be relied upon to regularly perform heavy duty tasks, such as using a hole saw to cut faucet spreads. That limitation sparked a race among manufacturers to develop a tool that was both strong and consistent.
"Over the past decade torque has been the big thing," Coe says. "A cordless drill driver ten years ago delivered 100 in./lbs. of torque, while today the market leaders are up to 300, 400, 500 in./lbs. It is a maturation process of replacing corded products."
Higher Voltage Vs. Increased Weight
In a cordless world, greater torque generally means higher battery voltage, and higher voltage means more weight. In terms of performance, today's 24-volt drill drivers are a far cry from the 6-volt models of yesteryear, and they have the heft to prove it. Which means operator fatigue has become a real issue with tool manufacturers.
Not surprisingly, considerable research has been devoted to coming up with new breakthroughs in battery technology. When it comes, that breakthrough promises to be the defining factor in the next generation of cordless tools. In the meantime, cordless tool manufacturers spend much of their waking hours refining their current offerings.
"If you look at battery technology," says Terry Tuerk, technical services director for Metabo USA, "nickel cadmium (NiCd) was the battery of choice for years and now there is a swing to the nickel metal hydride batteries (NiMH). NiMH gives you a longer run time per charge, it accepts a higher amount of current, and it has a stronger output than a NiCd battery. It also has a couple of downfalls. NiCd, depending on the charger you use, can be recharged anywhere from 1,000 to 3,000 times. NiMH batteries accept up to about 500 recharges before needing to be replaced, and they take longer to charge. NiMH is also more expensive than NiCd."
The industry standard for measuring battery life is expressed in amp/hours. Most professional grade drill drivers utilize 1.4 amp/hour batteries (although the 2.4 amp/hour variety is gaining in popularity) and provide two batteries as part of the initial sales package. But, just because your battery is rated 1.4 amp/hours doesn't mean it will last a full 1.4 hours between charges. In fact, battery life will vary depending on the temperature, job conditions and the task performed.
"I think what you want to look for is limiting your downtime," says Coe. "If you intend to use your cordless drill in high torque applications you need to make sure you have high amp hours in multiple batteries. If you are looking for a drill that just gives you good run time, then you want to look for something lightweight that has adequate or low torque."