How to Use an Impact Driver
An impact driver is easy to use and easy to misuse. These steps cover everything from loading a bit to driving a 6-inch structural screw flush.
Load a 1/4-inch hex impact bit, choose a low speed for small screws and a high speed for long ones, push firmly in line with the screw, and squeeze the trigger gradually. Let the impacting do the work and stop as soon as the head is flush. Most problems, such as stripped heads, snapped screws and split wood, come from too much speed, the wrong bit or not stopping in time.
On this page
Before you start
- Charge the battery. A weak battery slows impacting and leads to half-driven screws.
- Gather impact-rated bits that match your screws exactly. See impact driver bits.
- Wear eye and hearing protection. Impact drivers are loud while hammering. See safety rules.
- Know your controls: trigger, forward/reverse switch (center position locks the trigger) and the speed or mode button.
Step 1: Insert the bit
- Set the direction switch to the center (locked) position.
- Pull the collet sleeve forward, or simply push the bit in if your model has a one-handed collet.
- Insert a 2-inch power bit or a bit holder until it clicks and locks.
- Tug the bit to confirm it is locked.
Short 1-inch insert bits will not lock on their own. Use a holder. See how to put a bit in an impact driver.
Step 2: Choose the speed setting
| Fastener | Setting | Notes |
|---|---|---|
| Small screws, hinges, hardware, plastic | Lowest | Feather the trigger; consider a drill with a clutch |
| Cabinet screws, 1.5 to 2.5-inch wood screws | Medium | Assist mode helps if your tool has it |
| Deck and framing screws (2.5 to 3.5 in) | High | Slow down at the end to set depth |
| Structural screws and lag bolts | Highest | Pre-drill lags; use a socket adapter |
| Self-drilling screws into metal | Self-tapping or T-mode, or medium | Full speed strips the threads once through |
| Tapcon concrete screws | Low to medium | Stop the moment it seats |
Settings vary by brand. See speed settings and modes.
Step 3: Start the screw
- Place the screw on the bit (magnetic bits and holders help) and position the tip.
- Hold the tool with your dominant hand on the grip. Use your other hand on the tool body or to steady the screw for the first turns, keeping fingers clear of the screw's path.
- Align the bit straight in line with the screw. Most cam-out comes from angle, not torque.
- Squeeze gently to start the screw slowly for the first few threads.
Step 4: Drive it home
- Once the screw is started, increase trigger pressure. The tool will begin impacting as resistance builds.
- Keep steady forward pressure in line with the screw. Do not rock the tool.
- As the head approaches the surface, ease off the trigger.
- Stop as soon as the head is flush or just below. Continuing to hammer a seated screw snaps it, strips the wood or chews the head.
Step 5: Removing screws
- Flip the direction switch to reverse.
- Seat the bit fully and push firmly. Reverse is where most stripped heads happen.
- Start slowly. The impact action helps break stubborn screws loose.
- For seized or rusted screws, a manual impact driver is often better.
Driving bolts, nuts and lags
- Use an impact-rated hex-to-square adapter and an impact socket, or hex-shank sockets.
- Pre-drill lag bolts with the pilot size the fastener maker or your building guidance recommends.
- Use the highest setting, keep the adapter short and stop when the washer is snug. Do not keep hammering.
- Critical fasteners, such as lug nuts and structural bolts with a torque spec, must be finished with a torque wrench.
Full technique in how to drive lag bolts.
Drilling with an impact driver
With hex-shank drill bits, an impact driver drills pilot holes and small holes in wood and metal. Use a medium setting, let the bit cut and back out often to clear chips. For precise holes, large hole saws and masonry, use a drill. See can you drill with an impact driver?
Common mistakes and fixes
| Problem | Likely cause | Fix |
|---|---|---|
| Stripped screw heads | Wrong or worn bit, angle, too much speed | Exact bit size, new tip, straight alignment, lower setting |
| Snapped screws | Too much power; hammering after seating | Lower setting; stop at flush |
| Split wood | No pilot near ends or in hardwood | Pre-drill; stay away from edges |
| Bits snapping | Non-impact bits | Impact-rated bits |
| Bit falls out | Insert bit without holder | Use a holder or power bits |
| Screw goes in crooked | Fast start, no pilot | Slow start, pilot hole, assist mode |
More fixes in how to stop stripping screws.
Care after use
- Blow dust out of the vents and collet now and then.
- Store batteries indoors at moderate temperatures, partly charged for long storage. See battery storage.
- Replace worn bits before they ruin screws.
See impact driver maintenance for the full checklist.
Frequently asked questions
Do I need to push hard with an impact driver?
Push firmly enough to keep the bit fully seated, but you do not need to lean on it like a drill. Steady forward pressure in line with the screw prevents cam-out.
Why does my impact driver only start hammering sometimes?
That is normal. The hammer mechanism only engages when the fastener resists. With little resistance, it just spins.
Should I pre-drill with an impact driver?
Pre-drill near board ends and edges, in hardwood, for lag bolts and wherever the screw maker recommends it. Many modern construction screws are self-drilling in softwood.
How do I stop an impact driver from overdriving screws?
Use a lower speed setting, feather the trigger as the head approaches the surface, and release the moment it is flush. Some models have modes that slow down automatically.
Is an impact driver safe for beginners?
Yes, with eye and hearing protection, impact-rated bits and a firm two-point stance. It produces less kickback than a drill, which makes it easier to control on long screws.