Impact Driver or Drill - Which One Is Right For You?

Although both cordless drills and cordless impact drivers have distinct uses, they also have many similarities. In fact, for most tasks you could substitute one for the other and get the job done. However, in these cases usually one will work better than the other - it all depends on the project, your skills, and personal preferences.

How they work

A powered drill works with a simple electric motor. By squeezing the trigger, the motor turns on and spins the bit. Modern drills have variable-speed triggers, which means that the more you squeeze the faster the motor runs. Some have settings letting you adjust the top speed letting you customize for the current task.

Impact drivers also have an electric motor which is used to spin the bits. The motor is smaller with less torque, although often spins faster. But an impact driver has additional mechanisms - a hammer and anvil - that turn on when more power is needed. These mechanisms add much, much more power to the driver.

The hammers are spun at high speeds inside the motor. When they are moving fast enough, they strike the anvil. This gives a noisy sound to the impact driver, along with the power. The method also results in less back-torque on the users wrist and hand making it easier to use.

Which works better?

Each tool has different strengths. Not surprisingly, for drilling holes you would probably pick a drill. Most drills have better control at low speeds, allowing you to more precisely start holes. Additionally, to use an impact driver for drilling you either need a set of hex-shafted drill bits or a drill-bit chuck accessory.

An impact driver can be better in certain drilling situations, however. When making large holes using a spade-bit, for example, the high power and the internal mechanism will let it drill through with ease and without wearing down the battery as fast as with a cordless drill.

When driving screws, a drill with a screwdriver bit will work fine much of the time. For small screws, a drill is preferable because of tools combo kits manufacturers the fine control - an impact driver is so powerful, you could over-tighten or even break the screw head right off.

For most screwing tasks, however, the best choice is a cordless impact driver. The sudden impact action means that the power is delivered to the screw so quick that even in tough situations, the bit doesn't have time to come out of the screw head. This means no stripping of the head, and no need for a lot of downward force on the screw. Additionally, since there's no back torque, you can screw in long, long screws into hard woods easily - even one handed, if you need to.

When it comes to nuts or bolts, again the impact driver wins easily. An 18v impact can repeatedly drive in long lags without wearing down the battery, unlike a drill which will start to slow down after just one hard bolt.