How to Operate an Impact Driver

Operating an impact driver is fairly simple, if you have operated a drill, the basic functions of an impact driver is very similar to operate. Below we are going to go through how to operate each feature of an impact driver, and how to fasten and unfasten.


Impact drivers come with a variable speed trigger, the amount of pressure placed on the trigger will determine its RPM and torque power output, this gives you better control of the impact driver.

For example, if you are driving a screw into timber, you will want less RPM and torque power to start off with to get the screw in the timber, once a significant amount of the screw is in, you will want full power to drive most of the screw in quickly, once it is almost driven in, you may want to use less power to tighten it, so you don’t damage the surrounding material.

With the trigger, you will also get a forward and reverse switch which is located just above the trigger. Forward to fasten and reverse to unfasten.


This is where the Hex screw bit holder or Hex screw bit go into. Standard size screwdriver bits will not fit directly into an impact driver chuck and will require Hex screwdriver bit holder. Screw drive bits that are 50mm or longer will fit directly into the impact driver chuck.

To insert or remove the Hex bit, depending on model, you will pull the chuck forward or back to release the Hex bit. To insert the Hex bit, some models will allow you to push it in, some you will have to pull the Hex forward. There are many different Hex bits available, you can even get drill Hex bits, and use the impact driver as a drill.

Adjustable Power Output

All though you can control the power with the variable speed trigger, some impact drivers come with a switch that allows you to adjust maximum power output for RPM, torque and impacts per minute.

This is a good feature to have, for example, if you are driving cabinet screws, you don’t want to use too much power as you can damage them. Limiting the power output will make sure you don’t accidentally apply too much power and damage the screws and surrounding area

LED light

Nearly all impact drivers come with an LED light, this automatically comes on when you press the trigger, and usually stays on for a number of seconds after you have released the trigger.

Fastening and Unfastening Screws with an Impact Driver

Fastening simply means to tightening a screw, and unfastening means to un-tightening an screw, and is a simple action to perform with an impact driver.

Fastening screws

  • Select the right Hex screwdriver bit for the screw you are going to fasten
  • Insert the Hex bit into the impact driver
  • Make sure the impact driver is set to forward rotation via the small button above the trigger
  • Place the impact driver on the Screw head, and use the variable speed trigger to start off slow to drive the screw in
  • Once you feel you have enough of the screw in, press harder on the trigger to increase RPM to drive the screw faster
  • Once the screw head is almost flush, reduce the power via the trigger, until the head is flush with the surface, or tight to your preference, by reducing the power, you will be more precise, and less likely to damage the screw as the impacting function will kick in

Unfastening screws

  • Make sure the impact driver is set to reverse via the small button above the trigger
  • Place the impact driver into the screw
  • Start by using less RPM power via the trigger, the impacting function will kick in, and the screw will come out better, and chances of camming out the screw will be reduced
  • Once the screw is lose, increase the power to get the screw out faster

Uses of an Impact Driver

  • Impact drivers has many uses, it can be used as:
  • Electric screwdriver to build flat pack furniture
  • Drive the right screws into concrete
  • Drive screws directly into timber
  • Unfasten stubborn screws
  • Fasten and unfasten nuts and bolts
  • Use HEX drill bits, and the impact driver can become a drill

What to Take into Consideration Operating an Impact Driver

Impact drivers have massive amounts of torque, and with its impacting function, if driving screws directly into timber it is very easy to drive the screw all the way through the timber, or break the screw when driving into various other materials. Not only do you risk damaging the screw, but the surrounding area as well. Another issue is camming out the screw head if too much power is applied instantly.

Although impact drivers are a specialist power tool, they are very versatile when it comes to fastening and unfastening. You will hear many people say, once you have used one, you will never want to be with out one when it comes to fastening and unfastening tasks.

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Arthur Allen has been using all sorts of power tools for the last 27 years, gaining a lot of experience on how they work, how to determine what makes a power good, and becoming an expert on the subject through many years of real world trial and error. Not only is Arthur and expert in tools, but various building jobs as well.