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Using Impact Drivers

A few years ago, other than the noise of saws and nail guns, jobsites were pretty quiet. But today, on almost every construction site, you’re liable to hear the clacking of an impact driver. After all, most of us have become completely dependent on them for driving screws: they never strip out a head, even when you’re driving a screw in tough wood; even if you’re standing on a ladder reaching over your head, you can still drive a long screw without throwing your weight behind the driver; and you can drive handfuls of screws without tiring.

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Tools of the Trade and Fine Homebuilding (see Fine Homebuilding issue 196 and this online video) have recently published two great articles about the newest Lithium Ion models, which are much more powerful than our old 12v and 14v nicds. Some of the guys on our crew worked with the impact drivers used in the Tools of the Trade article.

The author of the article had to test the guns using lags instead of screws because the new 18v models drive too many screws on a single charge—they typically drove over a hundred 1/4-in. x 3-in. lags on a single charge (see photo, right), which means hundreds of 3-in. screws, maybe a thousand 1 1/2-in. screws!

But with all that torque, an impact driver is often the last thing I want to put in the hands of one of our new finish guys—it’s like handing a hammer to a two-year old. But with a few caveats, these high-powered drills are great for finish work.

Feathering the trigger

Impact drivers don’t have clutches, which makes them a bit dangerous in the hands of the uninitiated. The guys on our crew overcome that problem by ‘feathering’ the trigger. In other words, rather than squeezing the trigger down all the way—pedal to the metal—we pull the trigger in short spurts, which protects the screw from the full torque of the tool, especially as the head approaches the shoulder of a hole or the surface of the hardware. The tool never reaches full speed so that as soon as the impact action begins, we can stop driving the screw—usually just in time!

Light up dark corners

A lot of new tools, like miter saws, circular saws, and routers are showing up with LED lights and I love them, even though it’ll be another twenty or thirty years before I’ll probably have to start wearing glasses. Most new models of impact drivers have lights on them now, too, which makes them even more useful when you’re working in closets, cabinets or dark corners.

I wouldn’t have believed it if I hadn’t tried many of the new drivers, but the lights on each model are totally different from each other. Some of them work really well, some of them work okay, and some are plain terrible. Let me show you what I mean.

Read this article in its original format (with more images) at TiC Issue 1!


4 Responses to “Using Impact Drivers”

  1. Craig Brewster

    I would be lost with out my impact driver. I hardly ever use a cordless drill. They are so much better at driving screws and the size and weight of the drivers is another big plus.

  2. trimcat

    im onto my 2nd impact driver in 4 years, both bosch, the first being a 12 volt that came bundled with my table saw

    anyhow its a world of difference driving screws with these power horses. especially in renovation situations where they can fit in tighter spots. the torque they kick out is so much more than a conventional drill/driver. you can even drive lag’s for fastening deck ledgers.

    my only beef is that since the mass release of impact drivers. tool manufacturers have greatly reduced the torque that regular drill/drivers can put out. something that is needed if using a larger hole saw to drill through the ribbon to run a dryer vent out the side of a house or something

  3. Allan

    Ditto, years ago, my son and I build his large deck with a 12 volt impact driver and 2-batteried, we worked for days driving lag screws and 2-1/2- 3″ deck screws. Since then nearly all my tools are Bosch

  4. Willie

    “Thank you for this informative post on using impact drivers! I’m curious to know what types of screws are best suited for use with an impact driver, and are there any specific tips or techniques to keep in mind when driving screws with one?


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