How Does an Impact Driver or Drill Work?

Impact drivers are cordless tools that resemble power drills in many aspects. They do tasks such as tightening nuts and screws which need more power. Also, they loosen nuts and screws, which the traditional power drills are unable to take out. 

Although an impact drill can drill holes, it has a limitation that you must use drill bits with hexagonal shanks. Such drill bits are not available for all sizes. It also performs many operations, especially in jobs involving extensive use of fasteners.

An impact driver works by detecting resistance while screwing. It then overcomes this resistance by using a combination of both the rotational and the hammering mechanism. The hammering process compresses and releases the hammer using the spring. It then hits the output shaft to release the rotational force to it. The power then drives the screws with much ease.

An impact driver/ drill explicitly drives screws. It does the work with much torque and speed, which makes it ideal for stuck nuts and screws. It uses the collet that works with hex-shanked driver bits, unlike the cordless screws which use keyless chuck.

It has an impact function that uses the hammer and the anvil system. When in operation, the impact driver may encounter resistance. 

The impact system produces more power to overcome this resistance. It does this by contracting the spring and expanding to release the hammer.

The hammer releases a rotational force to the anvil while still turning. The anvil then releases the power to the screwdriver bit. The process repeats itself at a rate of 50 times per second to provide a turning force to the screwdriver bit. 

Impact driver as a drill sourced from here

The impact driver works to substitute the power drill if your goal is to have the work done. However, it would help if you considered the following few things before you engage the impact driver in drilling.

Are the Drill Bits Shank Fit for The Tool?

You should first check whether the drill bits have a hexagonal shape of the shank. This will be ideal if you intend to use it on an impact driver for making holes. Most of the impact drivers can only work with hex shank bits since their socket is hex shaped.

 Is the Impact of The Drill Rated?

It is essential to use impact bits, which should work with the driver only. This is because both standard and regular bits may bend or even burst when exposed to the high torque and the high impact. Using the recommended bits will give you excellent results.

The Impact Driver Has No Clutch and Has Limited Speed Options

Unlike many standard drills, impact drivers do not have a clutch. However, this contributes to their small size, which makes it ideal for use in compact spaces. 

Also, they are relatively slow in their operation compared to drills. This implies that you might take some more time to execute your drilling works using an impact drill.

How Do You Use the Impact Driver?

A set of drill bits

An impact driver and a drill work the same way as does. However, it has a quick-change and locking collet that holds the hex-shank drivers. Before you start using it, you have to install the bits then proceed to apply it.

Installing bits

Installing the driver bits is a bit easy. You only need to pull back the collet, drop the bit in, then release the collet. Just like a drill, it has a variable speed trigger, which rotates and releases a fast impact force to the anvil. This gives the tool much more power as compared to the drill and can work on tough materials with much ease.

After installing the bits, the tool functions quite well when used by a professional. One of the distinguishing features of the impact driver is that the tip of its bit stays in touch with the screw head. Hence, it does not slip while working as the drill does. 

 You can use the impact driver to:

  • Loosen bolts, nuts, corroded and over-torqued screws
  • To fasten long and thick fasteners into a hardened material
  • To drive/ remove screws with broken heads

However, the tool is not limited to the above functions and thus can apply the tool otherwise if fit.

Differences Between an Impact Driver and A Drill

Both the driver and the drill are different in many aspects, although they may look alike at first glance.

What Differentiates the Two?

  • Size: The power drill is relatively bigger than the impact driver due to the presence of the clutch.
  • Clutch: Power drills have a clutch, which reduces the over-tightening of the fasteners or damage on the drilling surface.
  • Chuck: The power drills have keyed or keyless chuck while impact drivers have collet, which holds the hex shanks.
  • Power and speed: the impact drivers produce more energy at a rapid rate. The process is automatic once the system detects resistance. On the other hand, power drills don’t have such much power since they use one gear.

Special bits for an impact driver

It would be best if you used individual bits that are impact rated and not any other. The standard ones may bend when used under high torque. Similarly, the regular bits may burst when exposed to the high-power impact.

Moreover, the impact drill bits shanks should match the hexagonal shape of the sockets; otherwise, they won’t work.

Do I Need A Drill or An Impact Driver?

Your choice of the right tool to use for your DIY projects primarily depends on the type of your project. It also depends on the reason why you need a drill. An impact driver drives thick/large fasteners. it can also be used for drilling using some special bits. It suits best for jobs that need much torque to for execution. However, the use of individual bits limits its application as a drill since they are not available for all sizes

On the other hand, power drills make holes as well as driving small fasteners that do not need much power. It is ideal in works that need precision.

Both the impact drill and the power drill can still marry well. That is, you can use the drill to make some precise holes, and then use the impact driver to apply the fasteners. So, you can prefer to have both of the tools at your toolbox since they complement each other. 


Both the impact drivers and drills are essential tools for both professionals and DYI woodworkers. However, both work well, depending on the nature of the project. As we have explained from the above article, both work tools in a very similar way. However, you will be swayed to pick either of the tools, depending on the accuracy and the size of your project.




I am a woodwork enthusiast who is in the Financial Industry. I come from a woodworking family and started handling woodwork tools from a young age. For me, it's not a hobby. its a way of life.

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