Why Use an Impact Driver?

Why is an impact driver an important addition to your tool box?

In a word:  TORQUE.  An impact tool gives you more driving power to drive screws, nuts, and bolts.  Remember the noise you hear in the auto garage or pit row at a car race?  That vibrating, impact noise you hear is an air driven impact wrench.  Today, that same technology is available in battery tools.  In fact, many NASCAR teams now use DeWalt battery impact wrenches on race day so they don’t have to worry about those pesky air hoses.

How Does an Impact Driver Work?

how-it-worksAs the name suggests, impact wrenches slam the drive mechanism with a tremendous amount of force, then back up and slam it again.  To better understand this concept imagine you are trying to knock down a brick wall with your car.  If you inched up to the wall, touched it, and then applied the gas you’d be able to exert a certain amount of force on that wall.  Depending on the strength of the wall it might move or it might not.  But if you backed up 10 yards, slammed on the gas, and hit the wall with some speed and momentum you’d have a much better chance of making a significant impact on that wall.  (To keep the attorneys happy, we must say that this is for illustration purposes only and not recommended.)  The same concept applies when thinking about a drill versus an impact wrench.  A drill is like pulling your car up to the wall gently, and then pressing on the gas.  The impact wrench is like hitting the wall with speed from 10 yards back.  The impact has a much more significant effect.

Pros and Cons of an Impact Driver

There are a few drawbacks to the impact driver which help set its role and place in your toolbox. Unlike traditional cordless drills, impact drivers don’t have adjustable chucks meaning you will not be able to use your old round bits. Instead, impact drills use hex locking bits with a releasable sleeve on the tip of the drill, or an anvil, which accepts sockets. Another drawback is the lack of clutch. On a normal drill the clutch will disengage the bit when a certain amount of resistance is reached. This helps to prevent screws being drilled too far or stripped. Impact drivers are fast and powerful, and without a clutch you could potentially ruin a job you’re working on if you’re not careful.

benefits-chartFor each con an impact driver has it seems to have 100 pros. Today’s light weight and powerful 20V Lithium driver produces a torque somewhere around 325 in-lbs, while an impact wrench has a torque somewhere around 1,600 in-lbs! A drill consumes a lot more power as it strains to deliver maximum torque and means you’re swapping batteries a lot more.

Since the drill bit and motor aren’t directly connected on an impact driver, you won’t have to experience the high-level torque while you work.  You also won’t have to exert as much force when driving screws because of an impact driver’s high rotational force.  All of this means less fatigue and reduced muscle strain.  This can make a significant difference on projects that involve driving a lot of screws, such as building a deck, installing tile backer board or screwing down sub-floor.

To put it another way, an impact driver has very little reactionary torque.  If you’ve ever gotten your hand smashed against a stud when cutting a hole with a drill, you’ll clearly understand what this is.  Reactionary torque is what twists up your wrist as you’re laboring to drive or drill on a traditional drill.  The impact driver efficiently delivers nearly all of its energy to the drive head instead of your wrist – dramatically reducing fatigue and risk of injury.

A Few Convenience Factors

convenient-usesThanks to modern innovation people have found ways to take a great product and improve it. An impact driver does not drain the battery like a drill will under maximum strain.  The lithium ion batteries that come with the Porter Cable impact driver that Koopman carries recharge in only 30 minutes! Plus, they will hold that charge even after being stored for extended periods of time. Impact drivers are also significantly smaller and lighter than drills, reducing fatigue. The snub-nose design allows you to get into hard to reach places and the lightweight design lets you use it with one hand, allowing a free hand to hold/steady yourself or your project. Finally, everybody’s favorite feature that’s available in many DeWalt models: a light that projects a beam forward that allows you to work effectively even in poorly lit areas.


The impact drill is an indelible tool that we can’t get enough of. If you’ve never used one on a project then you’re missing out! It could forever change the way you build.  It won’t replace your cordless drill, but it’s a perfect compliment to it.  Stop by a Koopman location today and try one out. Our trained staff will help you get outfitted with an impact driver that’s right for you, and give you the know-how about how to use it best!

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