The Difference Between a Drill, an Impact Driver, and a Hammer Drill
When putting together your DIY tool kit, you’ll quickly discover that there’s rarely just one version of a particular tool. Sure, there are Phillips-head and slotted-head screwdrivers, but even hammers —perhaps the most basic tool of all—come in a surprising variety, each designed for a different task.
When it comes to power tools, understanding the differences can be tricky. Take drills , for example: how do you know if you need a standard drill, a hammer drill, or some other “impact driver”-type tool? You can get ahead in your home improvement career without understanding these differences, but there comes a point when using the right tool will make your life significantly easier. If you’re still unsure about the differences between a drill, hammer drill, and impact driver, here’s the information you need.
Drill vs. Impact Driver vs. Hammer Drill
Drills, impact drivers, and hammer drills are all used to drill holes and drive fasteners, but they work differently and are well suited for different tasks:
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Conceptually, a drill is the simplest tool: your trusty drill spins a bit, delivering constant torque at various speeds. When the motor encounters resistance, it shuts off. This means that when the drill reaches its limit, it can’t do much to drive a fastener or drill a hole. A standard drill is good for both drilling and boring.
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Impact drivers also rotate the drill bit and deliver constant torque—until they encounter resistance. They then apply a rapid, perpendicular, hammering force, which temporarily increases torque beyond what a standard drill can deliver. If you’ve ever hit something sideways with a hammer to loosen it, or clamped a wrench and hammered the handle to loosen a stuck bolt, the same thing is happening here, but dozens of times per second. Impact drivers don’t have a clutch, so they continue to operate even when resistance is encountered. They are typically quite loud, and the vibration can tire your hands and forearms. As a result, impact drivers aren’t ideal for drilling—they’re best used for driving fasteners.
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Impact drills work like regular drills, but in hammer mode (which must be selected), they apply downward force (like a hammer driving a nail), as opposed to the horizontal force of an impact driver. An impact drill can be operated like a regular drill by disabling the hammer function—and, like a regular drill, the motor shuts off when resistance is detected. An impact driver in hammer mode is best suited for drilling holes in hard materials, but not for driving fasteners.
How to choose between a drill, impact driver, and hammer drill
Knowing how each of these tools works makes choosing the right one a little easier. In general, here’s when it’s best to use a drill, impact driver, or hammer drill for your project:
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Drill bits are precision tools ideal for driving small fasteners, such as standard screws, or for drilling holes in soft materials like wood or drywall. They’re a versatile tool for most small DIY projects, as well as for applications requiring greater control over the drilling or screwing process.
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Impact drivers are best used for working with dense materials, such as very hard wood, or large or long fasteners that require a lot of force to drive. If you’ve ever tried to drive a long screw with a drill and found it jamming halfway through, an impact driver might be the solution.
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Hammer drills are best suited for drilling or fastening into very hard materials, such as stone, concrete, or brick. In fact, using the hammer mode on lighter materials should be avoided, as it can cause damage. However, since most hammer drills can be turned off and used as regular drills, they can be a good all-around option.
Another difference is that impact drills and regular drills use a chuck that can accommodate a variety of drill bits, while an impact driver only works with 1/4-inch hex head drill bits.
Which one should you buy?
Since an impact drill can also be used as a regular drill, it’s the best option if you’re unsure which tool you need or want to avoid buying an additional tool for a future project. It combines the capabilities of a regular drill with the added power of impact. You can hold off on purchasing an impact driver until you’re really working on a project that requires one.