Last updated on January 2, 2022
When to use an impact wrench? An impact wrench is used for tightening and loosening medium to large lug nuts, bolts, screws, and fasteners.
It uses a high rotational torque without needing much effort exerted by the person using it. The energy of an impact wrench is stored in a rotating mass and then released to the output shaft to deliver the high torque.
The most common source of the power of an impact wrench is compressed air , but battery-operated impact wrenches are also available now and becoming more and more popular due to portability on construction sites.
How to use an impact wrench? Let’s start.
Step 1. Choosing the right type of impact wrench
A pneumatic impact wrench uses the power of gas under pressure, or compressed air.
It is also lighter since it doesn’t pack a battery or internal motor.
It is the most powerful type of impact wrench. However, it requires more maintenance, needing to be oiled, its air tank drained, moisture removed, etc.
An electrical impact wrench uses the power of electricity, instead of compressed air or pressurized gases.
An electrical impact wrench contains an internal motor for power. The weight of an electric impact wrench is much heavier because of the motor.
A cordless impact wrench uses the power of lithium batteries or a lithium battery, instead of compressed air or pressurized gas.
It is more convenient to carry around, but not as powerful as the pneumatic impact wrench.
If you want to fasten screws, you should be looking for an impact driver instead.
Step 2. Choosing type of socket
Specialty impact sockets are stronger compared to standard sockets, used with impact power tools that apply more torque.
They have an enclosed head that grips the entire head of the fastener so the socket won’t slip off, they are constructed securely to make sure they won’t fly off during the use of an impact wrench.
Impact sockets are typically made with chrome-molybdenum steel, adding elasticity to the socket which can bend or stretch instead of shatter due to its ductility while minimizing deformation or damage.
Can you use regular sockets with an impact wrench? Regular hand tool sockets are typically made from chrome vanadium steel  which is structurally strong but more prone to breaking when exposed to shock and vibration due to its brittleness.
Step 3. Choosing the right socket size
Choosing the right socket size is essential to the project that needs an impact wrench to be used.
The size of an impact wrench is the dimension of the drive anvil, the distance between the flat edges of the driving anvil.
Here are the most common socket sizes and their typical uses:
- 1/4-inch and 3/8-inch for working with bolts that are below 10mm in diameter and for more accuracy overpower
- 1/2-inch for a balance of precision and power being the most common size
- 3/4-inch and 1-inch for more professional work since these are the biggest sizes.
Here’s our guide to storing your sockets neatly.
Step 4. Preparation
Before operating an impact wrench, inspect the air-impact wrench for damage, need of repair, or missing parts, including assessing the condition of the air hose for pneumatic air impact wrenches and associated fittings.
Check the battery for any leaks and cords for any damages.
When operating an impact wrench, wear safety goggles, tie your hair back and secure it with a cap, don’t wear loose clothing, and wear hearing protection.
Step 5. Attaching the socket
Identify the socket you need for your project, depending on the size.
Match the nut measurement to the socket for compatibility.
Attach the socket to the handle by locating the socket’s hole, then placing the socket over the nut.
After attaching the socket, identify the correct direction for tightening and loosening.
Step 6. Impact wrench direction settings
For the impact wrench’s direction settings, place the rotation push button located above the trigger of the impact wrench in the correct direction.
For the Forward position, push the button forward. For the Reverse position, push the button back.
Step 7. Setting the torque, speed, or PSI
For setting the torque, speed, or PSI, check what kind of impact wrench you have to see if there are any controls for it.
If there are controls for torque, speed, or PSI, turn the ring to adjust the torque to the preset level you need on the numbered scale.
If there are no controls, either install an air pressure regulating valve between the air hose and the impact wrench or adjust the output with compressor valves.
The last two methods are only applicable to pneumatic models.
Step 8. Final checking before using
Analyze your work surroundings. Check if you are using the right socket size for your impact wrench and project.
Carry the impact wrench by the body and not by the air hose. Check if you are using the right amount of torque.
Always have a firm grip on your impact wrench to prevent slipping and injuries.
Dos and Don’ts for using an impact wrench
- Do prepare beforehand by reading the manufacturer’s instructions and guidelines.
- Do wear safety equipment when operating an impact wrench.
- Do use clean, dry air at the manufacturer’s recommended pressure (about 90 psi) to power the air impact wrench.
- Do use impact wrench sockets that are specifically designed for this type of tool.
- Do disconnect the air hose before installing or adjusting impact wrench sockets or performing tool maintenance.
- Do maintain your impact wrench tool.
- Don’t keep using the tool when you feel pain and discomfort from use.
- Don’t over-torque bolts and nuts with an air-impact wrench.
- Don’t use the impact wrench for tasks inappropriate for an impact wrench.
- Don’t leave your impact wrench exposed to weather elements like water and sunlight as it could damage it.
Using an impact wrench safely
When using an impact wrench to tighten lug nuts or bolts safely, always read through the manufacturer’s guidelines and instructions for operation.
When operating an impact wrench, wear safety gear and equipment such as safety goggles or glasses, hearing protection devices like ear muffs, and good-quality gloves.
Hold the impact wrench properly by the body. Be cautious of the output power of your impact wrench since it could snap smaller fasteners.
An impact wrench is a very convenient and powerful tool, useful for projects, delivering high torque power output without the user putting too much effort when working.
It’s a a must-have for every mechanic.
It is usually used for automotive repair, heavy equipment maintenance, major construction projects, and other D.I.Y projects that need the power from an impact wrench.
Hi, my name is David, and thanks for reading one of my articles.
As a construction cost estimator, and a car restoration enthusiast I share some of my skills here at Bangingtoolbox.
If you have any questions about your car restoration projects or if you have any queries about pricing a construction job, you can find out more about me here.