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The best impact driver

Impact driver bits are disposable and can wear rapidly. Invest in hard-wearing, quality spares (about $1 each), or you could be changing them every couple of minutes.
Impact driver bits are disposable and can wear rapidly. Invest in hard-wearing, quality spares (about $1 each), or you could be changing them every couple of minutes.

When you need to drive dozens of long or large-diameter fixings, no power tool can match the speed and efficiency of an impact driver. Fit it with a socket adapter, and you've got a versatile tool for the auto mechanic or engineer. However, the sheer variety can make choosing difficult, so the following guide explains the jargon and points out the key considerations. We've also chosen a few favorites. Our top pick, the DeWalt 20V MAX XR, offers exceptional quality and class-leading power in a surprisingly affordable package.

Considerations when choosing impact drivers

Today's impact drivers are invariably cordless tools. The key decisions are about voltage and battery, torque and speeds, and motor type.

Impact drivers have either 12 volt (V) or 18/20 volt power output. The latter are both effectively the same. There's a power surge when you press the trigger of any power tool, in this case giving an output of 20V. Within moments it settles down to 18V — its normal output. The only difference is how the manufacturers decided to describe them. (Perhaps they think 20V sounds more impressive!)

Essentially, a 12V impact driver is a light-duty tool. Typically, torque output is up to 1,000 inch pounds (in.lbs.). A 20V tool usually offers around 1,500 in.lbs., although the best get close to 2,000 in.lbs.

Torque is perhaps the main reason to choose between tools, but single-speed models take time to master — there's a lot of power generated, and it's easy to overdrive a screw or damage the head of a fixing. Multiple speeds means you can dial things down when you need a bit more precision.

There are two types of motors, brush and brushless. Brush motors are inherited from corded power tools. They're reliable and cheap, but they do wear out, and eventually the brushes need replacing. They're also quite power hungry, demanding more frequent battery recharging. Brushless motors are more expensive, but much better at managing battery power. Unless you're on a tight budget, the latter would be our choice.

We should also take a quick look at batteries. Voltage is obvious — it's got to be the same as the tool — but batteries are also rated for Amp hours (Ah). Voltage is the maximum output, and Ah is basically how long it will last. The smallest impact driver batteries are 1.5Ah. We prefer 2.0Ah. However, under most circumstances, 4.0Ah will run more than twice as long as 2Ah, so if you want to reduce downtime to a minimum, that's what we would recommend.

Features

It's good to have some kind of built-in lighting for working in dark spaces. Most impact drivers provide LEDs. Some also have gauges, indicating the remaining battery charge.

A belt clip is always useful, and it's nice to have a bag or case in which to store the tool. It's also worth considering the warranty, which can vary from one to three years.

BMP or IPM (blows per minute or impacts per minute) are sometimes quoted. While it's important that the hammer action is there to assist the torque, there's no real relevance in the actual numbers.

Price

The cheapest impact drivers are those sold as "bare tools" — you'll find 12V models for as little as $40. If you already have compatible batteries from another power tool from the same brand, it can mean big savings — but check carefully. Otherwise, you'll need to buy batteries and charger, and impact driver kits can often work out to be a better value. They start with single-battery kits from about $100, and even the best with twin batteries usually come in just under $200.

FAQ

Q. Do I need an impact driver as well as a drill/driver?

A. A drill/driver is a great all-rounder — but it has limitations when it comes to large-diameter fixings. If you're laying decking, for example, an impact driver provides consistent power for driving long screws fast through lumber such as western red cedar. Trying to do it with a drill/driver would soon get frustrating.

Q. Is an impact wrench the same as an impact driver?

A. No. An impact wrench is the kind of thing you see at the tire fitter. It's a tool used for removing lug nuts from wheels, and other heavy-duty applications. Although the underlying technology is similar, and you can use small sockets with the driver, the two tools are not interchangeable.

Impact drivers we recommend

Best of the best: DeWalt 20V MAX XR Brushless Impact Driver

Our take: High-performance kit for the demanding professional.

What we like: Powerful, 1850 in.lbs. driver with three speeds for great flexibility. All you need in one kit, including the case. Unrivaled reputation for quality, and actually very affordable.

What we dislike: Would prefer higher Ah battery. Some reliability problems — but not many.

Best bang for your buck: Milwaukee M12 Cordless Impact Driver

Our take: Small, light-duty model suitable for DIY use. Excellent value.

What we like: Decent torque considering it's only 12V. Reliable. Ergonomic. Neat ambidextrous belt clip. Trigger-activated LED and four-stage battery gauge.

What we dislike: Battery and charger extra (but still very affordable). Lower voltage limits versatility.

Choice 3: Porter-Cable 20V MAX Cordless Impact Driver

Our take: Full kit of impact driver, batteries, and charger. Ideal for the serious amateur.

What we like: A quality tool from a well-known brand at an excellent price. Light, compact, and powerful. Has work light and battery-charge indicator.

What we dislike: Batteries only 1.5Ah. A few owners report durability issues.

Bob Beacham is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds.

BestReviews spends thousands of hours researching, analyzing and testing products to recommend the best picks for most consumers. BestReviews and its newspaper partners may earn a commission if you purchase a product through one of our links.

Distributed by Tribune Content Agency, LLC.

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