A cordless impact driver is used for high-torque fastening: driving screws, lag bolts, and structural fasteners into wood, metal, and some concrete.
Bosch Professional describes cordless impact drivers as tools for high-torque fastening, built around rotary impact rather than steady drilling torque — which is why the tool feels different the moment it bites.
Jobs It Handles Best
Impact drivers are built for fastening jobs where a standard drill/driver struggles or stalls. Bosch and Metabo both position these tools around power-intensive screwdriving:
- Long decking and framing screws in dense lumber
- Lag bolts and structural fasteners in built-up wood
- Bolts, nuts, and other threaded fasteners needing tightening or loosening
- Concrete screw applications on professional-grade models — Hilti states its SID 6-22 covers everyday professional fastening across wood, metal, and concrete screw applications
That last item separates a shop-grade impact driver from a light-duty one. Impact cycles arrive in bursts, so the bit rotates in small, hard jolts instead of one continuous push — that burst pattern resists cam-out and forearm fatigue on long fasteners. It is also what makes the tool louder than the work suggests.
Materials, Fasteners, and Bits
The short list is wood, metal, and — on capable models — concrete screw applications. Wood and metal are everyday cases; concrete screws are a specialty task that depends on the model. Fastener types across manufacturer documentation cover screws, lag bolts, structural fasteners, bolts, nuts, and other threaded fasteners.
Most cordless impact drivers use a 1/4-inch hex chuck, often with a quick-change collet, designed for hex-shank driver bits — not standard round drill bits, a separate accessory system from a drill chuck.
| Spec | Bosch GDR18V-1400 | Real-World Meaning |
|---|---|---|
| Max torque | 1,400 in-lbs | Handles long decking screws and lag bolts that stall a drill |
| No-load speed | 0–2,800 RPM | Fast run-in on short fasteners |
| Impact rate | 0–3,600 IPM | Burst torque that resists cam-out |
| Chuck type | 1/4-inch hex | Accepts hex driver bits, not round drill bits |
| Body length | 5.9 inches | Fits between studs and joists |
| Weight | 2.3 lbs (bare) | Light enough for overhead work |
| Launch price | $129 kit | Entry point for an 18V-class kit |
What Not To Use It For
Impact drivers are fastening tools, and manufacturer descriptions focus on fastening rather than general hole-making. Treating one as your only drill is the most common mistake. Route elsewhere:
- Boring large holes in wood or metal — the hex chuck and impact action are not built for it
- Precision work where smooth, controlled feed matters more than torque
- Fasteners into materials the model isn’t rated for — concrete screws belong only to models the manufacturer lists for that use
Battery platforms are another trap. Cited specs are model- and platform-specific, so an 18V battery from one brand won’t fit another’s driver, and 18V systems differ between manufacturers. Confirm which platform you’re already invested in. If comparing brands, our tested cordless impact driver roundup walks through which models hold up on real jobs.
Safe Use
Manufacturer safety guidance is short and worth following exactly. Protect your hearing — impact screwing can cause hearing loss, so hearing protection is not optional. Wear safety glasses and gloves. Read the user manual before first use, and inspect the tool before each job to confirm good working condition.
The wiring warning is the one people skip. Official guidance requires holding the tool by its insulated gripping surfaces when a fastener may contact hidden wiring, and keeping the tool away from hidden wiring and pipes before you start. A stud finder and a quick scan cost less than a shock. Hilti’s overview of professional impact driver applications is a useful reference for matching a driver to the job.
FAQs
Can a cordless impact driver replace a regular drill?
No. An impact driver is built for fastening; a drill for making holes. Most drivers use a 1/4-inch hex chuck that accepts hex-shank driver bits, not standard round drill bits. If you bore holes regularly, keep a drill alongside your impact driver, or choose a model with a removable chuck.
Is a cordless impact driver too strong for small screws?
It can be, which is why most have a variable-speed trigger and multiple torque modes. Feather the trigger when seating small screws and short fasteners so you don’t strip the head or drive the screw below the surface. Practice on scrap material first if the tool is new to you.
What size battery do cordless impact drivers need?
The example models are professional 18V-class tools, and battery platforms are brand-specific. An 18V battery from one manufacturer generally does not fit another’s driver, so verify the platform before buying, especially if you already own batteries from a specific brand.
References & Sources
- Bosch Professional. “Cordless Impact Drivers” Source for GDR18V-1400 specs: torque, RPM, IPM, chuck, size, weight, and kit price.
- Hilti USA. “Impact Drivers — Learn More” Source for SID 6-22 use across wood, metal, and concrete screw applications.
- Metabo. “Cordless Impact Drivers & Wrenches” Source for manufacturer positioning of impact drivers as fastening tools.