Impact Driver vs Drill vs Hammer Drill:  Why So Many Similar Tools?

There are three different types of drill/drivers to choose from based on your project requirements.  Why three different drill/drivers? Do I want or need all three? Let’s take our time to understand the differences, why each is so unique and why you might want or need one or all of them in your bag.

I’m going to start by oversimplifying a bit.  This is due to the fact that many of the manufacturers have solved some of the initial problems and limitations by developing “hybrid” tools.   I’ll cover this again in the last paragraph.  The good news is there are some awesome options out there now.

Note: I’m going to use Dewalt as an example manufacturer just so I keep things simple.  This way we can focus on the differences that matter.

Fun FactThe Three Tools – At A Glance

The cordless drill/driver has been the most popular portable cordless tool of all time and I don’t expect that to change anytime soon.  It is the most versatile of all three and you very likely have had one in your tool arsenal for many years.  So what’s with the other two?

The drill/driver is the everyday multi-use tool.  The impact driver however is gaining popularity because of the ease at which it drives screws and bolts.  Where you used to struggle driving longer screws with the drill/driver, gripping tight and pushing hard up against your project, the impact driver works more effortlessly.  So, when you are working on a project that doesn’t require a clutch (the thing that keeps you from over torquing a project), this tool makes quick work of things.  Since I added the impact driver to my tool set I very rarely use the drill/driver anymore.  I reach for it only when I need to drive with precision leveraging the drill/driver clutch.

As for the hammer drill, well this one is pretty easy.  Its used almost exclusively on masonry projects.  When you need to sink an anchor into poured concrete you will quickly find both other drills inadequate for the job.  Once you grab the hammer drill you will be able to drill through the concrete with ease.

Lets talk about what makes these three tools so unique.

One Big Difference: The Drive System

This is one area that distinguishes one tool from another and is the key difference.  Lets run through them all.

The Drill/Driver – The Clutch

This tool has a continuous drive, multi-speed function with a clutch. The trigger provides you a variety of speed options based on your project and the adjustable clutch will allow you to control how much torque you apply to the project.  You are probably familiar with this feature.  On the Dewalt drill/driver, the collar can be rotated from torque setting 1 through 17.  The higher the number, the higher the torque applied before the drill clutch releases.  Once the tool applies that amount of torque the bit stops turning and the tool lets out a good rattle to let you know to let off the gas.  At the very high end of the torque settings you can lock out the clutch for “drill” function if you don’t want the clutch to kick in during drilling.

The Impact Driver – Rotational Torque

The impact driver does NOT have a clutch. Setting limits to the amount of torque applied has to be done by touch and trigger control. There is no “set it and forget it” function like on the drill/driver. This means you run the risk of stripping things out if you’re not careful.

Like the drill/driver, the impact driver provides a multi-speed function (however not quite as granular as the drill/driver) and operates very similarly to the drill/driver under low to moderate torque loads.  Once the torque gets to the point where you would hear or feel the drill/driver start to strain, the impact driver magic begins.  From this point on the motor no longer simply transfers the torque directly to the chuck or collet.  Instead, a clutch-like mechanism disengages the motor from the chuck or collet for a split second. The motor continues to turn building up momentum that is applied in one burst of torque as the clutch re-engages. This can happen up to 53 times a second.  The result is three to four times the amount of torque provided by the drill/driver.

The Hammer Drill – Downward Blows

As we saw above with the impact drill, the torque is increased through bursts of ROTATIONAL TORQUE applied by the clutch-like mechanism. With the hammer drill, force is applied DIRECTLY downward toward the project. Think of a hammer being hit repeatedly on the top of the drill as you’re drilling into your project. This force is so great (in bigger drills mostly) that it feels like a miniature jack-hammer in your hands.  That force makes small work of even the toughest masonry projects.

Which Tool Should I Buy?

The functionality gaps between all of these tools are blurring which is a GOOD thing for the consumer.  For example, Dewalt and other manufacturers provide a drill/driver that INCLUDES a hammer drill setting (DCD985 does for instance).  By rotating the collar from hammer drill, to drill, to clutch operation, you get more functionality in one tool.   You no longer need three separate tools to cover all of your bases.

My Two Cents:  You really ought to have a good drill/driver, the most versatile of the tools.  This leads us to the SECOND most important tool (for most of us) which is the impact driver.  I would take a hard look at the projects you are working on and the frequency with which you use these tools.    If you find that you’re working on more than one project a month consider investing in a impact driver.  I use mine almost daily and I reach for the impact driver more often than the drill/driver.  Lastly, unless you’re working with a lot of masonry, you can pass on the hammer drill.  If you really want to have that functionality consider investing in a drill like the Dewalt DCD985 which provides you with the best of both worlds, drill/driver and hammer drill.

Happy drilling & driving!  Let me know if you have any questions.