What Is an Impact Driver?
An impact driver is a power tool designed specifically for driving fasteners. While a drill/driver has versatility to handle some driving tasks, the speed and power of an impact driver make it the best tool for many repetitive and heavy-duty driving tasks.
How an Impact Driver Works
For standard driving, an impact driver works like a drill/driver: as you pull the trigger, the motor turns the chuck or collet and the bit to drive a fastener. But the key to the driving force of an impact driver is the hammer and anvil assembly. This mechanism engages when the bit encounters heavy resistance:
- A spring pulls the hammer back and then releases it.
- A pair of studs on the hammer strike matching arms on the anvil as the hammer rotates, turning the collet and bit with greater rotational force or torque.
- This increased torque powers the fastener through the resistance.
In addition to creating more torque, the impact action of an impact driver means the tool is less likely to twist against the rotation of the bit, making driving fasteners easier on the wrist.
An Impact Driver Needs Impact Driver Bits
The power of an impact driver requires impact driver bits to turn the fasteners. These bits are designed to handle the torque without breaking. An impact driver typically has a collet that accepts 1/4-inch bits with hex shanks. You can find driver bits that fit a variety of fastener head types, including:
- Torx® or star-drive bits
- Square-drive or Robertson bits
- Nutsetter or nut driver bits
- Phillips bits
- Slotted bits
And of course, you can find impact driver bit sets with a range of driver bit types and sizes.
Don’t use standard bits with an impact driver.
Impact Driver Features
While a typical impact driver can handle many driving tasks that require speed and high torque, there are available features that make this power tool even more useful.
Torque Output
Higher torque output, typically measured in inch-pounds (in-lbs), improves driving performance when working with dense materials or large fasteners. A basic, light-duty impact driver might deliver up to 1,500 in-lbs of torque while a pro-grade impact driver might have a torque output of up to 2,500 in-lbs.
Impacts per Minute
Impacts per minute or IPM measurements indicate the speed of the hammer striking the anvil of the impact driver once the bit meets resistance. Higher IPMs typically mean faster, more efficient work when driving in tough materials.
Rotations per Minute
Rotations per minute or RPM measures how fast an impact driver turns a bit. An impact driver that has higher RPMs can handle standard, low resistance driving tasks faster than a comparable tool with lower RPMs.
Drive Size
While most impact drivers work with 1/4-inch hex-drive bits, you can find some that also accept half-inch square-drive sockets. These tools can function as impact drivers or, for handling larger fasteners, impact wrenches.
Battery Performance
- Battery Voltage: Higher voltage batteries can deliver more power to create more torque. A 12-volt to 20-volt impact driver can handle most do-it-yourself projects while an 18-volt to 24-volt impact driver is suitable for heavier or pro-grade jobs.
- Battery Amp-Hours: In general, batteries with higher amp-hour ratings have longer runtimes than lower-amp-hour batteries.
- Charge Time: Battery size and charger capabilities are the key factors in how long it takes to charge an impact driver battery.
- Battery Platform: An impact driver that uses the same battery platform as other power tools or lawn equipment lets you swap batteries between tools and projects, so you always have a battery charged and ready to work.
Brushed Motors
Many newer impact drivers feature brushless electric motors. While models with brushed motors are typically less expensive, a brushless motor offers more power, better battery management and a longer life, versus a comparable brushed motor. Get the details on these two motor types with our guide to brushless and brushed power tool motors.
Convenience Features
Look for impact driver features that make the work simpler and more convenient, including:
- A belt clip
- An LED light
- A spare battery
- A tool bag or case
- An included charger
Impact Driver Uses
While an impact driver doesn’t replace a drill/driver, it’s often the best tool for driving tasks that require speed or power. Follow the tool manufacturer’s use instructions but below are some common examples of what an impact driver is used for.
When to Use an Impact Driver vs. a Drill
Once you have an impact driver, you’ll no doubt discover many uses, but here are some examples of tasks where an impact driver excels:
- Driving long screws and large lag screws for assembling a deck or pergola or framing a structure
- Driving lots of screws for installing deck boards, fence pickets, building furniture and woodworking
- Removing stuck or overtightened fasteners in machinery or automotive applications
- Driving concrete anchors into pilot holes to anchor a pergola on a concrete pad or fasten brackets to a concrete block wall
As useful as an impact driver is, it’s not the best tool for every job. An impact driver typically doesn’t have an adjustable clutch, so it’s not as precise as a drill and the right tool for:
- Drilling
- Driving small fasteners
- Driving fasteners that are easily stripped or damaged
- Driving fasteners if overtightening the fastener is a concern
- Driving in materials that are easily damaged
It’s a good idea to have both an impact driver and a drill/driver so you’re ready for different projects. Our comparison of impact drivers and drills tells you why and shows you the similarities and differences of these tools, along with projects that are suited for each. If you haven’t got a power drill yet, our drill/driver guide shows you your options. A power tool combo kit is a great way to buy both tools on the same battery platform.
An impact driver and a drill/driver are just two of the tools a DIYer needs in a tool kit. Read our tips for stocking a tool box that lets you handle common projects around the home. We’ve also got a power tool guide and a mechanics tool guide that help you find the tools you need to take on even more projects.
Impact Drivers and Safety
The power an impact driver supplies to your work requires attention to safety. Follow the tool manufacturer’s safety guidelines, but here are some key points:
- Disconnect the impact driver from power before changing bits, making adjustments or performing maintenance.
- Use bits designed for an impact driver and your application.
- Use the right fastener or anchor for your work.
- Wear safety glasses and hearing protection.
- Wear a respirator when driving in materials that generate dust.
Impact Driver Key Takeaways
While an impact driver doesn’t replace a drill/driver, it’s a smart addition to your tool kit that lets you handle more projects efficiently. An impact driver is the perfect tool for driving tasks that require speed, use long fasteners and for projects with dense materials. Here are the key points to keep in mind as you shop:
- Higher torque output and IPMs are best for heavy-duty driving jobs.
- Higher RPMs are good for fast, light-duty driving.
- Batteries with higher voltage and more amp hours give you a more powerful tool and longer runtime.
- Make sure you buy bits suitable for an impact driver.
- Use an impact driver according to the manufacturer’s instructions.
- Wear safety glasses, hearing protection, and, as necessary, a respirator.
It’s easy to find the best impact driver for your projects when you shop Lowes.com by battery power, brand, price range and more. Plus, we’ve got impact driver bits and sets that make the tool capable of handling a variety of fasteners. You can also stop by your local Lowe’s and take a look at your impact driver options. A Lowe’s Red Vest associate can help you find an impact driver with the power and features you need, as well as the bits and materials you need for a successful project.
Impact Driver FAQ
Knowing the answers to these common questions helps you choose the best impact driver for your projects.
Should I Buy a Drill or an Impact Driver?
It’s a good idea to have both a drill and an impact driver in your tool kit. A drill is highly versatile for a variety of drilling and driving projects, but an impact driver simplifies driving jobs with long fasteners, dense materials and lots of screws.
When Should I Not Use an Impact Driver?
Use an impact driver according to the manufacturer’s instructions. Since an impact driver typically doesn’t have an adjustable clutch, it’s not the best tool for driving small fasteners or driving fasteners that might strip or snap easily or projects where overdriving or overtightening is a concern. And while some drill bits might fit an impact driver, an impact driver is not the correct tool for drilling.
Can I Use an Impact Driver as a Drill?
An impact driver isn’t the right tool for drilling applications. A power drill is designed for drilling and will be a safer, more effective tool for drilling. Always use a power tool according to the manufacturer’s instructions.