“But they look exactly the same,” you think to yourself as you browse the endless online listings of impact drivers and drills. You can’t decide which to get and, even though you’ve heard all the buzz about impact drivers, you’re still not entirely sure how they differ. What I know now, I wish I knew before making my purchase choice.
Impact drivers’ internal mechanism is very different from a drill. A drill may have a hammer function, adding pulses that “hammer” the drill bit forward. An impact driver uses pulses to turn a screw or bolt with greater torque. Impact drivers also use a locking collar instead of a chuck.
In short, an impact driver specializes in torque (rotational force), whereas a drill specializes pushing a drill bit forward. Yes, drills can also be used to drive screws, but there are a few factors to consider before making your purchase choice.
The Humble Drill
The cordless drill has been around for several years and is often the first power tool most people buy because of its incredible versatility.
Most cordless combi drills come fitted with chucks. A chuck uses three prongs, or fingers, to grip onto round drill bits. Chucks also work fine with hexagonal screw bits, but if you don’t tighten them up properly, the screw bit can slip out, onto the floor and into the abyss where things are never found.
This chuck is the key to the versatility of the cordless drill because you can go from drilling a hole to driving a screw in moments. Most cordless drill chucks also don’t require special tools to loosen and tighten them, further simplifying the process.
Where drills shine, quite obviously, is in drilling holes. Generally, drills come with an impact (or hammer) function built-in. The mechanism of this impact is in the same direction as the drill bit. In simple terms, the impact turns a drill bit into a spinning nail, rapidly striking it from behind as it spins.
This hammer action is especially useful for drilling into cement or concrete where the drill bit can effectively chisel through the material. It’s not practical when drilling wood and metal, however. You will probably ruin the project or the drill.
The Impact Driver
Impact drivers are a (reasonably) recent addition to the world of power tools. Or, rather, they have recently had a massive surge in popularity.
Where a drill comes with a chuck, an impact driver comes with a locking collar instead. This collar has a quick-release mechanism and is made specifically to accept hexagonal driver (or screw) bits.
Collars are considerably better at locking onto and securing a driver bit in place. Driver bits made specifically for impact drivers have indents where the collar locks onto, preventing it from falling out.
These collars are terrible at holding onto round drill bits, however. I say “terrible” in the sense that it’s impossible. But there is a workaround which we will look at later.
When it comes to driving screws, impact drivers are as good as drills are at making holes. It’s their bread and butter. This is partially because of the way the bits lock into place, but it is primarily due to the unique impact action of the driver’s mechanism.
Whereas a drill hammers behind the drill bit, an impact driver hammers in a circular motion around the base of the driver bit. As soon as the impact driver meets resistance, it will hammer in a circle, adding massive torque to the screw.
As a result, the impact driver can drive much bigger screws, much deeper into denser materials than a drill.
Understanding the mechanical differences between an impact driver and a drill is only the first step to choosing the right one. You also need to consider how effective they are at doing each other’s jobs.
Can You Drive Screws With A Drill?
Whether you can drive screws with a drill may seem like a pointless question because we have been doing it for years, but just because it can do it, doesn’t mean it’s great at it.
You can tell by simply looking at the screws in any house whether a drill was used to put them there and, in many cases, leave them there without a hope of getting them out. This is because drills are particularly good at stripping screws and ruining bits.
While it is true that, with the correct technique, you can cut down on stripping those screws, “correct technique” and “violent frustration”, at least in my house, aren’t exactly on speaking terms. It’s always when I’m rushed for time to fix something (already frustrated) that I end up stripping a screw beyond recognition.
As I briefly alluded to earlier, drills don’t have the sheer torque force of an impact driver. As soon as you run into resistance, the drill tends to lose grip on the screw, slip, and chew away at it like a piranha.
If you do manage to keep the bit in the screw head, you will find that at a certain point of resistance, after nearly bending your wrist into a pretzel, the drill just stops. You are now at risk of killing your drill, so it’s best to accept defeat.
Upon hitting this snag, an impact driver will keep turning away and drive that screw all the way down, and it will do so without straining your wrist. The action of an impact driver also makes it far less likely to slip and strip screws. Not impossible, just considerably more anger-proof.
Can You Drill With An Impact Driver
Don’t let the fact that round drill bits don’t fit into the collar fool you. There are special bits with hexagonal shanks (the end inserted into the collar), making it possible to drill holes with a driver.
In fact, due to the increase in torque, impact drivers can be better than regular drills at drilling holes in dense material. But it’s not all good news, and they do have their pitfalls.
Firstly, because you need special bits, you can expect to pay slightly more and deal with the increased rarity of certain drill bits. However, because impact drivers are so popular, these challenges may change with supply and demand.
Secondly, you may find it challenging to make precise holes, in part due to the driver’s action and also thanks to the slight play between the bit shank and collar. Although bits in a driver are locked so they can’t fall out, there is more play than a drill bit in a chuck.
Finally, without the traditional hammer action of a drill, you are not going to get very deep into a brick wall. You may see the driver turning but making little progress. A drill, on the other hand, would kick into hammer mode and punch straight through.
Here is a comprehensive video covering the big differences between an impact driver and a drill.
Should You Get An Impact Driver Or A Drill?
The purchase price isn’t a solid argument favoring either the drill or the driver because there isn’t a significant difference when comparing apples with apples. A specific make and model drill is going to be more or less equivalent to its driver sibling.
That being said, here are some tips on helping you choose.
Firstly, they are often sold as a package deal. If you can wing it, get both. You really won’t regret it. Most contractors need both, and most DIYers should use both (even if they don’t technically need to).
If, however, you can only afford one, you should consider your need first. If you drill more holes than drive screws, then get the drill. The inverse is also true.
Also, consider what you need to drill or screw. For example, if you mostly need to drive crews but occasionally drill into cement, consider the drill instead. If you drill more holes but never into cement and need to drive the occasional difficult screw; get the driver.
I own the drill, and I regret the decision in hindsight. Not because my drill is bad, but because I also own a reasonably big hammer drill (I call her Big Bertha). I use the hammer drill to do most of the drilling work, whereas my cordless drill is used as a screwdriver. In this case, an impact driver makes far more sense.
There is a substantial difference between an impact driver and a drill. Although both can do the other’s job to an extent, they are at their absolute best when used as a team. Drills are great at drilling holes into tough materials, but not the best at driving screws.
The action of the impact driver makes it great at driving screws into almost anything, but it’s not the best of drills. Consider your needs carefully. If you can only buy one, strongly consider the driver and save up for a drill afterward.