Impact Driver versus Impact Drill - Tool Guide

Impact Drivers are relatively new tools on the market. In fact, I can still remember my first experience with one. It was about one o'clock in the morning and I was at a mate's place debating our favourite topic… power tools.

Without warning, he quickly jumped up and said, "Ooo, I just bought an Impact Driver! You must check this out".

Me: "What's an Impact Driver?"

Him: "It's sort of like a drill, but it sucks at drilling. You mostly use it for screws and stuff".

Me: "Err, why wouldn't you just use a drill? It sounds like a waste of money."

Him: “You’ll see…” *said with confident smirk on face* 

His previous concerns about waking his wife and kids were quickly forgotten. It was now time for a late-night tool demo! Two pieces of structural timber were selected for a butt joint. He dug out the largest screws he could find – the sort of screws that would normally need a pre-drilled hole. And then… “RZZZZZ, DA DA DA DA DA DA!”

I stared in disbelief as the enormous screws sunk into the wood like hot fudge. "Damn! Do that again!"

They may look tiny next to most conventional drills, but when it comes to driving large fasteners, Impact Drivers feature phenomenal performance.

Admittedly, my initial scepticism of an Impact Driver's need over a conventional cordless drill were convincingly replaced by some credit-card swiping a few days later.

DIFFERENCES BETWEEN AN IMPACT DRIVER & IMPACT DRILL

While Impact Drills are highly versatile tools and great for most people who need to put a hole in something (wood, steel, plastic and, to some degree, masonry), they do have limitations when it comes to sinking large fasteners. This includes screws, wall plugs, coach bolts and more. 

There are two reasons for this…

Camming Out: Large screws require large amounts of torque. As this torque increases, the force needed to push the drill forward and prevent the bit from camming out and stripping the screw head also increases. Worse yet, if the problem happens in reverse. When trying to remove the screw you'll then be left with a fastener that can neither be turned "in" nor "out".

Because Impact Drivers use an impact force instead of rotational force to drive screws, they transfer very little force into your wrist and can be  effortlessly operated one handed.

Impact drivers have largely eradicated this problem because, in many ways, they operate similar to an air wrench – like the ones you see in tyre shops.

Ordinarily, a wheel spanner requires large amounts of rotational force to loosen a lug nut. However, because an air wrench uses a knocking/hammering effect instead of a progressively higher load, minimal effort is needed to loosen overly tight wheel nuts.

Unlike traditional drills that utilize a chuck system for holding bits, an Impact Driver uses a quick-changing hex drive, which enables fast and convenient bit swapping.

To some degree, an Impact Driver is really just a scaled-down, battery driven version of an air wrench, but instead of lug nuts, its primary purpose is to tighten and loosen screws and other fasteners.

This brings us to the next point…

ROTATIONAL FORCE

Most high-end cordless drills have enough torque to drive large screws and fasteners; however, the downside to all that rotational torque is that it needs to be controlled by the user. This is why high-torque cordless drills typically have long stabiliser bars to help resist or fight back against the drill's torque delivery. 

So, while it may be true that a top-tier cordless drill can do most things that an Impact Driver can do (and more), a drill requires a lot more strength to counter its rotational forces when driving large fasteners. Of course, do this 100 times a day and you’re going to be exhausted.

An Impact Driver does not replace the need and versatility of a traditional Impact Drill, but as a specialist tool, it complements a drill's weaknesses.

In contrast, an Impact Driver's ability to create a hammering effect significantly reduces how much rotational force is needed / resisted, as well as the tool's need for a larger, bulkier, more powerful motor.

This is one of the reasons why Impact Drivers are surprisingly compact, lightweight and punch way beyond their weight class – literally and figuratively.  

When comparing Makita's top-of-the-line Impact Driver to their top-of-the-line Impact Drill, the driver weighs just 884g, while the drill weighs 1.68kg. At almost half the weight, the Impact Driver is significantly easier to use for sustained periods.

Interestingly, it's believed that Impact Drivers were initially engineered for astronauts. I can’t verify the claim, but it certainly makes sense. The alternative is your entire body spinning around the drill in zero gravity.

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WHAT AN IMPACT DRIVER IS USED FOR

Back on earth, these specialist features make Impact Drivers ideal for repetitive work and jobs in tight spaces where a conventional cordless drill would be too bulky, tiring and cumbersome. That said, Impact Drivers are perfect for decking, cabinetry, and heavy-duty structural work. 

Note the difference in size between Makita's brushless Impact Driver and the brushless Impact Drill featured below.

The ease with which an Impact Driver completes these tasks is mind-blowing. It's incomparably more time-efficient than a conventional cordless drill – especially if you're having to pre-drill a hole first.

However, suppose your screw-driving needs are limited to occasional tasks around the house. In that case, an Impact Driver's specialist application will be an over-investment, and you’d be better off getting a conventional cordless drill with adjustable torque settings and variable speed control.

PROS AND CONS OF AN IMPACT DRIVER

On that note, consider these pros and cons before buying an Impact Driver…

PROS

• Unrivalled fastener-driving performance 
• Remarkably compact relative to how much force they apply
• Surprisingly lightweight and easy to operate for extended periods
• Significantly reduced chance of stripping screws
• Far less strength is needed to control them
• Less likely to sustain a wrist injury 
• Excellent battery life and efficiency 

CONS

• Incredibly noisy
• Overperformance can easily drive screws too deep
• Although it can be used as a drill to some extent, an Impact Driver is a specialist tool that sacrifices versatility for all-out screw-driving performance
• Typically costs more than a conventional cordless drill

BPM ToolCraft boasts one of the largest selections of Impact Drivers in South Africa, as well as a wide range of Impact Driver prices. You can browse our full range here.