When to Use an Impact Driver Instead of a Drill—and Why a Diablo Drill Bit Set Belongs in the Cart

Use an impact driver when you're driving screws. Use a drill when you're making holes. That's the short answer, and it's still the right answer after five years of buying tools for a maintenance team. If you only need one tool tomorrow, and tomorrow's job is fastening, buy the impact driver. If it's drilling, buy the drill.

Most people buy the tool first. I've seen too many jobs go sideways because the bit set was an afterthought. So here's the longer answer: the right driver matters, but the bit on the end of it matters more.

Why I'm the one saying this

I'm not a contractor. I'm the office administrator who manages purchasing for a company with about 400 employees across three locations—roughly $120,000 a year across eight vendors. I've been doing this since 2020. I process somewhere between 60 and 80 orders a year. Maybe 180 if I count every spare-drill-bit reorder. Actually I'd have to check the system before putting an exact number on it.

I don't use these tools all day. But the people who do use them report back to me when something doesn't work. I hear about snapped bits, stripped screws, and the job that took an extra hour because someone used the wrong tool. That's why I get picky about the details.

The straight answer

A drill spins. An impact driver spins and hammers. The bursts of torque are what let an impact driver drive screws without cam-out. It also means an impact driver should not be your default for drilling holes—the pulsing action makes the bit wander.

So when to use an impact driver instead of a drill? Every time your goal is to put a fastener in or take one out. Screws, lag bolts, self-tapping metal screws, and stuck bolts are all impact driver work. Drilling clean holes in wood, steel, or concrete is drill work.

Why the bit set is not an afterthought

Here's where I get firm. A $200 driver with a $2 bit still performs like a $2 bit. The bit touches the work. The tool just spins it.

'The bit is the weak point in the system.' — our tool supplier, who has been selling to industrial accounts for 15 years.

Our maintenance carts carry a Diablo drill bit set. It covers most everyday tasks: pilot holes in steel, masonry anchors in block, cabinet hardware, and light wood drilling. The carbide tips last longer than the budget alternatives. And the Diablo logo is laser-etched onto each bit, which makes it easy to identify the good bits and spot a cheap replacement someone threw in. If you see a set with a clear Diablo logo on the package but blank bits inside, that's a red flag. We had that happen once with an unauthorized supplier in 2023—or 2022, I don't want to give the wrong year—and those bits didn't earn their place back in the drawer.

I have mixed feelings about branded accessories. On one hand, they're an easy upsell. On the other, I've seen a no-name bit round out a screw head and turn a 20-minute install into a 2-hour rework. The cost of the bit is tiny compared to the cost of that call. Trust me on this one. A stripped screw head is not just a mechanical problem. It's a visual reminder of a sloppy install. That's a brand image issue for us, not just a hard cost issue. The quality of the bit is the quality of the finish.

When to use an impact driver instead of a drill

Bottom line: use the impact driver for fasteners. Here are the jobs where it wins:

• Driving deck screws or wood screws into framing.
• Driving self-tapping screws into sheet metal.
• Removing rusted bolts with a hex-shank socket adapter.
• Driving long lag bolts where a drill would twist out of your hand.

You can use a drill for some of these, but it's slower and harder on the wrist. An impact driver is the no-brainer choice.

Drilling still needs a drill

For holes, go back to the drill. An impact driver can accept hex-shank drill bits, and some of the impact-rated bits do okay. But the steady rotation of a drill gives you more control and a cleaner hole. If you're drilling concrete, use a hammer drill or rotary hammer. That's not what an impact driver is for.

Where the rule has exceptions

An impact driver can be too much of a good thing. If you're assembling furniture with soft particleboard, the impact will over-drive the screw and strip the hole. Use a drill with the clutch set low. If you're doing finish work where the screw head needs to sit precisely, use a drill and a careful hand.

That's the same reason I don't order a combination lock barrel bolt for a door that needs a deadbolt. It looks close, but the hardware and the lock system are designed for different jobs. Tools are no different. You need the shank, the tip, and the driving action to match the work.

I know this from at least one mistake. We needed 10 bolt cutters for a crew. The request came in as literally '10 bolt cutters.' I didn't ask for a size. I assumed standard was standard. It wasn't—the crew needed longer handles for leverage, and the 24-inch cutters we ordered didn't do the job. They went back. That order taught me to spec out every accessory request, from cutting tools to drill bits. The same approach applies here: don't grab an impact driver just because it's in reach. Pick the tool for the fastener, the material, and the precision you need.

And one more thing. Buy from a supplier who gets you the genuine item. I learned to check the Diablo logo on the physical bits, not just the package. Because a good bit set is only good if every bit in it is real.