Best Impact Drivers

Buying guide for Best impact drivers

A good impact driver is a powerful and versatile tool. It will breeze through jobs an ordinary drill/driver can't cope with.

If you’re shopping for a new impact driver, you’ll find plenty of options. This is good news in some ways, but the bounty of choice also presents some challenges. Voltage, torque, rpm, bpm ... there's a confusing array of specifications to consider and compare.

Impact drivers are noisy due to their percussive action. Every one we initially tested was above the 80-decibel safety limit, so ear protection should always be worn.

Why buy an impact driver?

A standard drill/driver does everything an impact driver does, so why might you want to spend the cash on an extra tool? In a nutshell, it comes down to power.

An ordinary cordless drill will do dozens of jobs around the home and garden. Everyone should have one. But try using one to put a dozen three-inch screws through decking planks, and you won't get very far. Cordless drills just don't generate enough torque.

An impact driver is designed for jobs like this. In addition to being able to apply vastly increased twisting force to the screw, an impact driver provides the rapid hammer action needed to deliver considerable additional force. It makes for a powerful combination, driving screws and other fixings almost effortlessly.

Choosing an impact driver

So what should you look for when shopping for an impact driver? Our investigations covered the following topics, each of which we delve into below.

• Power

• Torque

• Speed

• Hammer Action

• Additional Considerations

Power

Cordless impact drivers now dominate the market to such an extent that corded models are all but impossible to find. That being the case, the question becomes one of battery power.

• Voltage: The voltage designations manufacturers use can lead to confusion. You'll see 12-volt, 18-volt, and 20-volts impact drivers for sale. Clearly the 12-volt models aren’t as powerful, but what about the 18- and 20-volt models? Those numbers are surprisingly close together.
  
  In truth, it's a different interpretation of the same thing. Somewhere in the small print, you'll see that 20-volt batteries are actually nominally 18 volts. Some might say this is a bit deceptive. Manufacturers call it marketing! So effectively, 18-volt and 20-volt batteries are the same. They deliver considerably more power than 12-volt models – and that’s what most people will want. However, while these tools are relatively easy to handle, 12-volt impact drivers remain popular with those who have reduced physical strength.
• Amp Hours: Another aspect of battery power to consider is Amp hours (Ah). Higher Ah figures mean that a battery maintains peak performance for longer and drops off less rapidly. Ah is an important consideration if you're going to be using an impact driver all day – though high Ah batteries are usually quite costly.
• Recharge Time: Finally, you’ll want to note the recharge time of the impact driver you’re considering. Recharge times vary from around 20 minutes to an hour or more. The best product for you depends on your needs. A professional won't want to be waiting around for a long time for a battery to charge, but an amateur might not mind.

Torque

Torque (twisting force) is clearly a major factor when doing (or undoing) fastenings. Impact drivers are known for their exceptional torque. You can expect figures of around 1,000 inch pounds (in. lbs) from a 12-volt tool and in excess of 1,800 in. lbs from 18/20-volt models.

That said, torque without control can be excessive. If all 1,000+ in. lbs. came in at once, it would almost certainly tear the impact driver out of your hands. Because of this, impact driver triggers are progressive, allowing you to increase power gradually.

Speed

In addition to torque, impact drills can be rated for speed in rpm. Faster speed gets screws and other fixings fastened more quickly, so it ought to be a benefit. However, speed figures are not always quoted, not even by top manufacturers. The implication is that there’s always enough rpm to do the job.

Our research confirmed that assumption, but there is an additional feature on some impact drills that's well worth considering: variable speed. Many top impact drivers offer two or three speed choices. Effectively, they have a gearbox. This gives different torque ranges and thus more finesse for smaller fixings where full torque could actually strip threads or damage heads.

Hammer action

All impact drivers have a hammer action that jolts the screw. This is a very effective feature, but again, it's one where some manufacturers quote a figure and others don't bother. Our own investigations returned figures of between 3,000 and 4,000 blows per minute, depending on the model. Hammer action is a feature that's vital to efficient operation, but it’s not a feature that is necessarily “better” in one tool than another.

Additional considerations

• Consider buying an impact driver with a work light to illuminate dark corners. The best work lights have a time delay, allowing you to see the area for 20 or 30 seconds after the trigger has been released.

• Consider a tool with a battery charge indicator. This can be useful.

• Consider an impact driver that comes with a storage bag for tidiness and a belt clip for convenience.

Some recent impact driver designs incorporate the battery within the handle. This makes for a slender appearance, and at first, our testers found this attractive. However, most had gotten accustomed to putting an impact driver down and having it stay upright thanks to the bulk of the battery. Slimline models tend to fall over. It's perhaps a minor factor, but some people did find it frustrating when they went to reach for it, particularly if wearing gloves.

Impact driver prices

Inexpensive

Budget impact drivers from well-known brands start at between $60 and $70. You'll usually get a single battery and charger. If you're only going to use this kind of tool occasionally for short periods, a budget-priced impact driver could be an adequate solution. But batteries on tools of this quality often discharge rapidly, and they take a while to charge again. It soon gets frustrating if you have to keep stopping in the middle of a job. An extra battery is the solution, of course, but that's another $30.

Mid-range

For that same $60 to $70, you could get a high-quality, durable impact driver from one of the market-leading manufacturers – but it will be a bare tool only; no battery or charger. By the time you've bought those extras, you'll have spent well over $100, and probably closer to $150.

Expensive

If you want a comprehensive impact driver kit with two batteries, a charger, and a case or carrying bag, you'll pay anywhere from $170 to $300, depending on specification. Voltage often has little impact on price. Some 12-volt models are pricier than their 18-volt counterparts. Unless you have physical issues, we recommend the more powerful tool.

Tips

• Consider more than just torque when choosing your tool. Maximum torque isn't everything; modern impact drivers deliver plenty of that. What you want is control – the ability to turn the tool up to drive long screws into cedar decking or down to drive self-tappers into sheetrock.

• Be aware that the chuck on an impact driver is only designed to accept hexagonal bits (usually 1/4 inch). It doesn't open and close like the self-centering chuck found on ordinary drills and drivers. However, socket adaptors are available to extend the tool's usefulness, and most only cost a couple of dollars.

• Expect to pay around a dollar apiece for good bit replacements from recognizable brands. Many impact drivers only come with one bit, and these tools can wear them out rapidly. When you're looking for replacements, gold titanium finish versions look good, but in tests, they don't offer any significant advantage. The same can be said for so-called “impact-rated” bits.

Torque figures sometimes appear huge, but bear in mind they're given in inch pounds (in. lbs), not the foot pounds (ft. lbs) that are more commonly used. Inch pounds are only 1/12th of a foot pound.

FAQ

Q. What's the difference between an impact driver and an impact wrench?

A. An impact driver is a bit like a cordless drill/driver on steroids: it does a similar job but with lots of extra torque plus a hammer action for continuous work. It can drill holes and secure long fastenings where an ordinary driver would struggle.

An impact wrench is primarily an auto tool that is used for undoing wheel nuts or other parts on vehicles.

Q. Will I get a better deal if I buy a bare tool?

A. You might, particularly if you already own cordless tools from the same brand and have compatible batteries. You need to check carefully, though, as this isn't always the case.

Otherwise, you'll need to buy at least one battery and a charger. You'll need two batteries if you want to continue working while one is recharging. Each of these things adds to the cost, so you may want to consider a kit option, as these sometimes work out to be cheaper.

Q. Which is better, a brush motor or a brushless motor?

A. Brushless motors are better every time. The reason: brush motors wear out quickly, are less efficient at transmitting power, and are often noisier. The main reason they're still around is that they're considerably cheaper to produce. There's nothing wrong with a brush motor in principle. If you want a cheap impact driver for occasional use, it's a viable solution. You'll pay more for an impact driver with a brushless motor, but you'll get a more durable, virtually maintenance-free tool.