What’s The Difference?!!

What’s The Difference?!!

Cordless Drill VS Impact Driver–COMPARISON

Chandra Buwana – While every tradesperson I know has one and uses one of these tools daily, there still seems to be a lot of confusion amongst homeowners and wires about how exactly this tool differs from a standard drill. In this post, we’re going to discuss. What both of these tools do and how and when to use them. Let’s get the terminology straight this is a drill, technically an 18-volt cordless drill. This is an impact driver. They’re both rotary tools in a gun shape that are used for turning different types of bits.

But how they turn those bits can be highly different. See, a cordless drill is basically just a spinning machine. The drill uses a chuck and jaws to clamp down on the shaft of a drill bit; the drill’s motor applies constant torque to spin that bit. This means that drills are great for boring out holes where a fast constant spin rate is necessary to keep cutting through woods smoothly. They can be used with various drill bits such as standard twist bits, paddle bits, Forstner bits, hole saws, and many more.


But drills can also be used for turning driving bits as well that. I mean bits that are used explicitly for driving fasteners. Those bits include Phillips bits, flatheads, star bits, square bits, and even nut drivers. For a long time, this was pretty much the only tool people reached for when they wanted to drive a fastener. I mean, there really weren’t any other tools that could do the job effectively until these came along. Impact drivers are almost exclusively used for just driving fasteners. That’s their primary function, and the amazing thing is even though they’re smaller, they deliver way more force than a standard drill, so how do they do it?

The Differences

The real difference is in how the tool is engineered and how it transfers that force. As I said before, a drill just spins. The jaws rely on friction to hold the shaft of the drill bit in place. Still, an impact driver is a far more complex tool in two spins, but it can also sense resistance. Hence, as you begin driving a fastener, the tool will turn the bit like a drill. Still, when resistance increases, it activates another mode, sort of a super mode. It sounds and looks like the machine needs more torque to drill the wood.

source: https://www.dewalt.com/NA/product/images/3000x3000x96/DCF894B/DCF894B_1.jpg

What’s happening is that the tool is basically disengaging the motor from the drill bit then re-engaging it over and over again in fractions of a second. So instead of the tool applying constant torque, it only applies it in little quick bursts. The net effect of this is that it drastically reduces the amount of force transferred into your arm.

But it amplifies the force that gets transferred into the drill bit, making the impact driver easier to hold and operate. Still, it makes it far more effective at driving fasteners than a drill. It can drive huge fasteners that you would never even attempt to use a drill on, certainly not without pre-drilling. As I said before, the problem with using a drill to drive fasteners is that the tool applies constant torque. So the moment you pull the trigger, the bit immediately starts spinning, and the only thing keeping the drill bit in the head of that fastener is your hand and your wrist in your arm. Your muscles and joints have to counteract the force of the drill. If they fail to do, so you’ll get something that’s called camming out.

source: https://www.dewalt.com/NA/product/images/3000x3000x96/DCD796B/DCD796B_1.jpg

It’s a problem that every DIY is known and hates. It’s when the drill bit slips out of the screw head, spins around real fast, and makes a mess of the bit slot. When this happens, you have a screw that can no longer be driven in or back down. It’s like the most frustrating thing that can occur when you’re driving fasteners. Still, with the impact driver, this problem basically never happens. That disengagement feature prevents rapid binding, and as a result, it stays right in the screw slot where you want it. I really can’t overstate what a game-changer this was for the construction industry before impact drivers came along if you wanted to send in a bigger fastener, even say a three-inch screw, you had to pre-drill every hole. Either switch bits and drive a screw or keep another drill on hand with a driver bit in it and even then, it still might be difficult to drive two fasteners.

People ask 

Is can I drill holes with my impact driver?

And the answer is yes, you technically can, but to be honest, I’m not a very big fan of this. First off, you have to get drill bits with a hex shank and are therefore made to go into an impact driver. Call it smooth shank drill bits, and even slot shank drill bits won’t go in there, but more importantly, I just don’t think impact drivers are great for drilling.

You’ll know that you really want a constant speed and torque for effective drilling. Your standard drill is way better suited for supplying. I don’t like having to keep all sorts of crazy custom drill bits for my impact driver, especially when it’s not that great at drilling and I already have a drill. I know people out there are going to disagree with me on this. Still, for my money’s worth, after using both these tools in the field daily. That’s how I feel I like to use a drill for drilling and a driver for driving. The good thing is that these two tools are very frequently together now; they’ll come in 18 or 20 molt sets they’re not that expensive. The new ones are way more efficient than my old dinosaurs.


The last thing that I’ll say is that I do still just prefer cordless drills for driving small or delicate fasteners drills are just more sensitive. They have lower torque. They have clutches to prevent overdriving impact drivers so strong that it can be hard to keep them from burying a fastener. It’s like using a sledgehammer to swat a fly sometimes, so when I’m driving little hobby screws or decorative screws, I will typically switch back to a cordless drill with a driving bit in it the future. 


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