Cordless drills and cordless impact drivers each have distinct strengths. That being said, there is also a lot of overlap in their usage. In fact, there is so much overlap some people often wonder if it’s worth having both tools.
On the job site, or even around the home, lugging both around can get cumbersome. Depending on the task at hand, one of the two may be much more effective at getting the work done. In this article we are going to explore those situations and see which – if any – is more versatile.
Physical Operation
First let’s get an idea of what makes the drill and impact driver different from a technical standpoint.
Drill
- A standard power drill rotates the bit using a conceptually simple electric motor. By squeezing the trigger switch, the motor turns on and begins spinning.
- The triggers are usually variable-speed, meaning that the more you squeeze, the faster the drilling. Many also have a speed setting allowing you to adjust the top speed/torque depending on the needs.
- Some drills sport an adjustable chuck with various settings. When the torque required to turn the bit reaches the setting’s threshold, the clutch disengages the drive shaft from the motor. This stops the chuck from spinning while letting the motor spin free with a click-click-click. This feature can prevent someone from driving a screw too far into the material and splitting it, as well as help prevent stripping of the screw head.
Impact driver
- Powered impact drivers also have an electric motor to produce an initial rotation, like a drill.
- The motor is much smaller, however, and doesn’t produce as much torque as the drill. The torque comes from additional components – called the hammer and anvil – that kick in once the extra power is needed.
- The spinning motor whirls the hammers up to speed, at which point they smack the anvil and transfer all their energy in a sudden impulse. This repeats thousands of times a minute, and adds up to a hefty bit of torque.
- Since the energy is built up over time and then delivered in strong impacts, the reverse torque on the users hand and wrist is greatly reduced.
Task Performance
Drilling
As you might expect, a drill is usually the better choice for drilling holes. Better control is one of the main reasons to use a drill. With the impact driver it may be harder to line up and keep precise holes if you are working with fine construction. Additionally, hex-shank drill bits are harder to find and more expensive than the regular round-shaft drill bits.
However, in certain drilling tasks the impact driver is better. When hogging out large holes with a 1″ spade bit, for example, the battery on a cordless drill will wear down quickly. On an impact driver, however, the high torque and the hammering action will power through with no trouble.
Driving screws
With smaller screws, a drill will work fine. With soft, brass screws, you may even prefer the drill for better control – the impact action might start up just at the wrong moment and shear off your screw head! Additionally, if you are concerned about noise for whatever reason, a drill would be the better choice.
But, for general screw-driving tasks, the impact driver is almost always the best pick – for a number of reasons. They are lighter, they have more torque, the impact action prevents cam-out from stripping the screw heads, and the higher torque means no problem working with long screws. Even one handed.
Nuts and bolts
While you can get socket and nut driver attachments for both tools, this one is no contest. An 18v impact driver can seat long lags with little bogging down, over and over, while a cordless drill will start to slow down and eat up the battery life with even one.
The bottom line
If the focus is on pure drilling of holes with the occasional need for driving screws, a drill will be just right for you. But if your main need is for driving screws (laying down a deck?) or other fasteners, then an impact driver wins hands down. The lighter weight and longer battery life, combined with the ease of use and low-recoil, make a cordless impact driver an essential part of your toolbox.
