A reader asked a series of great questions, about whether to complement their cordless drill with an impact driver.
The short answer is yes – impact drivers deliver higher torque than most cordless drills, and provide performance benefits with respect to application speed.
Not everyone might need an impact driver, but there are definitely benefits even when a cordless drill can power through tougher fastening tasks.
Without understanding how torque ratings translate into real world applications, I can’t decide if adding Milwaukee’s entry-level M18 impact driver to my tool bag would be worthwhile.
I currently have an M18 Drill-Driver (2801-20) with a Torque rating of 500 in-lbs and have come close to needing more torque power on a couple of occasions.
I don’t want to find myself in the middle of a repair in an awkward, difficult to access space where insufficient driving force would cost me more in time, energy, potential injury, etc. by not having an impact driver available!
So, I’m curious what DIY-Homeowner situations/materials I could run into, where others had wished for torque over 500 in-lbs, if not over 1,000?
There are a lot of overlapping questions here. The biggest question I see is whether John should upgrade to an impact driver or not, but I’ll have to work my way there.
When digging into brands’ product spec sheets or user manuals, they will sometimes provide guidance as to their tools’ application limits.
A tool brand might say their cordless drill has a maximum drilling capacity of 1/2″ in steel, or 2″ in wood. These tend to be rough guidelines, and many brands don’t provide these application limits.
You’re not going to find a torque table that assigns torque levels to real-world tasks.
Let’s say you want to drill a 3/4″ hole in wood. The same drill might deliver different output levels when drilling the same size hole, depending on the type of wood and type of drill bit.
It’s hard to identify exactly how much torque one needs in a drill. Most of the time, it’s a binary decision – either a drill has enough power, or it doesn’t.
I would say there are 2 classifications of cordless drill torque.
Compact – 300-600 in-lbs torque
Higher Power – 650-1000 in-lbs and up
With a cordless drill, the higher speed setting delivers lower torque delivery, and the lower speed setting delivers higher torque delivery.
Because of this, impact drivers will typically deliver faster fastening application speeds. With an impact driver, the faster the speed, the greater the torque delivery, due to how it works.
When driving larger or longer fasteners, you will have to exert effort to hold the cordless drill steady. If you don’t, the rotational energy can twist the drill from your hands. Impact drivers deliver non-reactive torque, and so there’s far less worry about kickback sending the tool spinning.
The 2801 is Milwaukee’s M18 compact brushless drill. The next step up would be their pricier M18 Fuel model.
For driving tasks, such as John indicated being interested in, an impact driver would be a great addition.
Cordless drills, with their adjustable torque clutches, are still fantastic for driving smaller and medium sized fasteners. But for larger or longer screws, or things like lag bolts, impact drivers often have speed and torque advantages.
Back to the original question, as to how a drill or driver relates to a DIYer’s household needs. What material are you drilling into? Wood studs through drywall? How old is the wood? Are there knots? What types of screws are being used? Do you drill pilot holes first?
There are too many variables to be able to say “this is how much torque you need to drive a #10 wood screw.”
In my experience, it typically comes down to trial and error, except when the application can be well characterized. In a factory production line, a self-threading screw might be driven into a plastic housing at an exact torque. But in residential and many commercial environments, materials change, as do the fasteners or accessories being used. The torque required to drill holes can vary wildly, even from hole to hole with no change in material or drill bit.
In a DIY or home environment, drilling larger holes in harder wood or harder metals such as steel will typically call for greater torque than the roughly 500 in-lbs compact drills can deliver.
The same is true for driving larger or longer fasteners, such as 3-inch lag screws into 2x construction lumber.
I can build an outdoor raised garden bed from 2x cedar or cypress wood boards far quicker with an impact driver than just a drill. I use a compact cordless drill for quick pilot holes, and then an impact to fasten everything together.
Even when using smaller fasteners for certain parts of the construction, an impact driver is quicker. Not only that, it’s more compact and lighter, too, which is very welcome when working overhead.
It’s a great idea to start with a compact drill. Personally, I use compact drills more than heavy duty models, as I don’t have to drill larger holes too often. But when I need a hole saw, larger drill bit for wood, or other more demanding drill bit, compact drills are rarely enough.
An impact driver is, in my opinion, an indispensable complement to any cordless drill.
The higher torque is part of the reason, but it also comes down to application speed.
Even if one were to upgrade to a heavy duty or extreme torque cordless drill, most impact drivers will complete the same fastening tasks in a fraction of the time.
Referring to our guide to Milwaukee cordless drills, their top of the line M18 Fuel 2903 and 2904 brushless drill and hammer drill deliver 1400 in-lbs max torque, and with 0-500 and 0-2100 RPM speed ranges.
To get that 1400 in-lbs max torque, you’ll need to be in the 0-500 RPM speed range.
Let’s say you go with Milwaukee’s M18 compact brushless impact driver, which is a $99 promo at Home Depot right now (and seasonally) for the tool with a battery and charger. It delivers up to 1600 in-lbs max torque and 3200 RPM. In most cases, it should outperform Milwaukee’s best cordless drill in fastener driving tasks.
John said that they have:
come close to needing more torque power on a couple of occasions
If you’re pushing your cordless drill to the limit, it might be a good idea to expand your tool kit.
For drilling tasks, a higher power drill might be a good option. For fastening tasks, I would definitely recommend an impact driver, not just for its higher torque but also its speed, compact size, and lower weight.
Do you agree or disagree with my opinion on this? How would you answer the same question?