Impact Drill: What It Is and When Do You Use it?
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Impact drills, better known as impact drivers, are handheld tools designed to drive screws fast. We're here to help you decide if you need one.
If you found this article by Googling “What is an impact drill?” you probably meant “impact driver.” There’s technically no such thing as an impact drill. There are drills, and there are impact drivers — different tools. Impact drivers have one main function, driving screws fast and well. Drills, also sometimes called drill drivers, can drive screws, too, but not as effectively. They’re better at boring holes. Drills and impact drivers have many similarities. They’re both handheld and can be cordless or corded. They both spin when a trigger is squeezed. Most models of drills and impact drivers have variable speed. But there are some key differences you need to understand when deciding if you need one or both tools.
Impact Driver vs. Drill
The main difference between a drill and an impact driver boils down to power and rotational action. Unlike drills, impact drivers have quick release shanks that accept all one-quarter inch hex driver bits. Impact drivers produce lots of rotational force, capable of driving the largest wood screws in seconds.
Internal mechanisms allow impact drivers to produce more torque than drills, and in quick bursts. These bursts or “impacts” happen up to 50 times a second, giving impact drivers their name. They also rotate their bits in a two-steps-forward-one-step-back pattern, engaging and driving screws more effectively than drills.
Impact drivers tend to be more compact and lighter than most drills, but impact drivers usually deliver more power for a given size of tool while also keeping the driver bit more completely engaged with the screw head. This last advantage is the main feature people notice when they use an impact driver for the first time. “Hey, driver bits hardly ever slip and spin within screw heads when I use this impact driver!’
Are Impact Drivers and Hammer Drills the Same?
Some people confuse impact drivers with hammer drills. Like regular drills, hammer drills are distinct from impact drivers and made for a different purpose. They’re essentially regular drills with the added ability to vibrate bits back and forth rapidly while spinning. This makes for much quicker drilling in concrete, brick, stone or blocks. It’s this vibration (a kind of rapid hammering, really) that gives hammer drills their name.
Do You Need an Impact Driver?
If you need to drill holes and drive the occasional medium-sized screw, a regular drill will suit you fine. If you’ve got a deck to build, a plywood subfloor to install, a tree house to screw together or any other job involving lots of wood screws, consider investing in an impact driver.
It’ll cut down your work time significantly, while giving you the satisfaction of driving large screws into wood in just a few seconds. Like all power tools, if you invest in an impact driver, be sure to use it safely. Wear safety glasses, keep your hands, clothes and hair clear of the tool during use, and avoid workspace clutter that might cause an accident.
Choosing an Impact Driver
Most modern impact drivers are battery powered, and their batteries typically come in three sizes: 12, 18 and 20 volts. Higher voltage means more power and torque, but the difference between 18 and 20 volts is in name only.
DeWalt is the only cordless tool company that measures their battery voltage with tools at rest, advertising these as 20-volt cordless tools. While this is a true number, all so-called 18-volt tools from other companies also deliver 20 volts under no load conditions. DeWalt’s 20-volt tools deliver 18 just like 18-volt models, when under load. This is why there’s no power difference between 18- and 20-volt tools, all else being equal.
More power is good if you want to drive lots of large fasteners. But keep in mind higher voltage also means larger, heavier batteries, and a impact driver that’s harder to slip in and out of your tool belt.
Another consideration is brushed versus brushless motors. Drivers with brushless motors are somewhat more expensive, but also more efficient and powerful, while generating less heat and having longer battery run time between charges.
Finally, consider choosing a model with variable speed so you can harness more or less torque depending on how hard you squeeze the trigger. DeWalt, Milwaukee and Makita are some of the brands that produce high-quality brushless impact drivers.
Want to bore holes with an impact driver? It’s possible. A handful of companies offer collections of drill bits that have the kind of one-quarter inch hex shank that screw driver bits use. Slip one into your impact driver, then make some holes before driving screws.