Best Impact Wrenches: Small Compressors, Big Power

An impact wrench is a versatile tool with a million uses, but it needs a compressor to run. There are many compressor brands, tank sizes, and output pressures to choose from, so it can be challenging to find the right one for your impact wrench. The best air compressor for an impact wrench will depend on the size of the wrench, with different compressors suited to 1/4-inch, 3/8-inch, 1/2-inch, and 3/4-inch impact wrenches. The larger the wrench, the more air it needs to function.

For a 1/2-inch impact wrench, a compressor that delivers around 4 to 5 CFM (cubic feet per minute) at 90 PSI is recommended. A 20-gallon capacity compressor will avoid delays between tasks. A 6-gallon compressor is the smallest size that can run an impact wrench, but you will need to wait a few minutes between uses for it to refill.

Some highly-rated air compressors for impact wrenches include the Eagle EA-5000 Silent Series 5000 Air Compressor, the Makita MAC5200 Big Bore 3.0 HP Air Compressor, and the PORTER-CABLE C2002 Pancake Compressor. The best choice will depend on your budget and specific requirements, such as noise level and portability.

Best Impact Wrench for Small Compressor

Air compressor features to look out for

When choosing an air compressor for an impact wrench, there are several features to consider to ensure you get a machine that suits your needs. Here are some essential aspects to keep in mind:

CFM and Tank Size:

Start by looking at the CFM (cubic feet per minute) rating, which indicates how much air the compressor can move per minute. While impact wrenches use air in short bursts and don't require as much CFM as continuous-running tools, you'll still need sufficient CFM to drive the bolts. If the CFM isn't enough to keep the tank full, you'll need to take frequent breaks to let it recharge.

For impact wrenches, a higher CFM is generally better, and we recommend getting the highest CFM you can afford to ensure you have enough air to complete the job. The CFM requirement will depend on the size of your impact wrench. Typically, a 1/2-inch wrench needs a minimum of 5 CFM at 90 PSI, while a 3/4-inch wrench requires 7 CFM at 90 PSI.

Along with CFM, consider the tank size, which determines how long you can use the impact wrench continuously without the motor switching on. Smaller tanks (2 gallons) are suitable for short tasks, while medium-sized tanks (6-16 gallons) offer more capacity. For continuous use or running multiple tools, opt for a large tank (over 30 gallons).

Portability:

If you plan to move your air compressor frequently, portability is crucial. Larger compressors with tanks of 60 gallons or more tend to be heavy and less portable. Some may require multiple people to carry them, so they are better suited for a fixed location in a garage or workshop.

Smaller air compressors with tanks of 20 gallons or less are generally more portable and easier to carry or wheel around. If you need to take your compressor with you to job sites or different locations, opt for a compact and lightweight model.

Oil-Free vs Lubricated:

Air compressors come in two varieties: oil-free and lubricated. Oil-free models are more environmentally friendly, require less maintenance, and are typically used for lighter applications. On the other hand, lubricated compressors tend to be more powerful, last longer, and are better suited for heavy-duty use.

If you only need an air compressor for occasional light-duty tasks, an oil-free model may be sufficient. However, if you plan to use your impact wrench frequently or for demanding applications, a lubricated compressor might be a better investment.

Noise Level:

Air compressors can be quite loud, so if you're concerned about noise levels, look for a model that operates quietly. This is especially important if you have neighbours nearby or want to use your tools without disturbing your family or colleagues. Some air compressors are designed for quiet operation, producing as little as 70 decibels of noise, while others may be as loud as 90 decibels.

Additionally, consider the vibrations emitted by the compressor. Strong vibrations can cause the machine to move around or even walk across the floor, which can be annoying and potentially unsafe. Look for features like stable bases or suction cups to minimise vibrations and keep the compressor in place.

Other Considerations:

• PSI (Pound-Force per Square Inch): While CFM is crucial, don't neglect the PSI rating, which indicates the maximum pressure the compressor can achieve. Higher PSI can be advantageous for certain tasks, like removing rusted lug nuts.
• Recovery Time: The recovery time depends on the CFM and the size of the tank. If you use your impact wrench frequently or need quick recovery between bursts, look for a compressor with a higher CFM and a larger tank.
• Regulator: A durable and adjustable regulator is essential for controlling the PSI and CFM output. Ensure it's easy to use and adjust.
• Drain Valve: A well-placed and easy-to-use drain valve is necessary for removing condensation and water from the tank to prevent rust and corrosion.
• Durability: Look for a sturdy build with durable materials like cast iron or aluminium. Consider the pump life and the overall expected lifespan of the compressor.
• Thermal Overload Protection: This safety feature is helpful, especially if you plan to use the compressor for extended periods, as it will protect the motor from overheating.
• Price: Finally, consider your budget. Air compressors can range from a few hundred to a few thousand dollars, depending on the features and specifications. Balance your needs with your budget to find the best value for your money.

By carefully considering these features and matching them to your intended use, you can choose an air compressor that will power your impact wrench effectively and efficiently.

Air compressor tank sizes

For portable air compressors, the tank size is an important consideration. Smaller tanks, such as those around 5-10 gallons, are more lightweight and easier to transport. On the other hand, larger tanks, such as 20-gallon or 30-gallon options, offer a greater air capacity, allowing for longer continuous use without needing to refill.

When choosing a tank size for a reciprocating air compressor, it is recommended to consider the tool with the highest CFM (cubic feet per minute) requirement at the required PSI. By multiplying this CFM requirement by 1.25 or 1.5 and then rounding up to the closest gallon size, you can determine the minimum or recommended tank size.

For example, if you have a 1" impact wrench that requires 40 CFM but only have a 30 CFM air compressor, you may opt for a 12-gallon air receiver tank to compensate for the difference.

Additionally, the type of air compressor also plays a role in tank size selection. Rotary screw air compressors, for instance, may not require a tank at all, as they supply a continuous uninterrupted air stream.

For stationary air compressors, the sizing process becomes more complex and typically requires a qualified engineer. The ideal tank size for these applications depends on various factors, including air consumption, pressure variations, compressor size, pipe or hose size, and control system strategy.

In summary, when selecting an air compressor tank size, it's important to consider the intended application, portability needs, tool requirements, and the type of air compressor being used.

Air pressure and airflow units

Air pressure and airflow are two key considerations when choosing an air compressor for an impact wrench. Let's delve into these concepts and explore why they are essential for optimising the performance of your impact wrench.

Air Pressure Units: PSI

PSI, or Pounds per Square Inch, is the unit that measures air pressure in an air compressor. It indicates the force at which the air is being compressed and delivered to the impact wrench. The higher the PSI, the more powerful the air output. When selecting an air compressor, it is recommended to opt for one that can provide at least 90 PSI, with 120 PSI or more being ideal for enhanced performance.

Airflow Units: CFM

CFM, or Cubic Feet per Minute, quantifies the volume of air flowing through the compressor per minute. This measurement is crucial because it determines how much air the impact wrench receives while in use. A sufficient CFM rating ensures that the impact wrench receives an adequate supply of air to function effectively.

The CFM requirement varies depending on the size of the impact wrench. Here are the typical CFM ratings for different impact wrench drive sizes:

• 3/8": 3 CFM @ 90 PSI
• 1/2": 4-5 CFM @ 90 PSI
• 1": 8-10 CFM @ 90 PSI

To ensure optimal performance, it is recommended that the air compressor's CFM rating is at least 3/2 times the minimum requirement of the impact wrench. For example, a 1/2" impact wrench typically needs around 5 CFM, so the air compressor should provide at least 7.5 CFM at 90 PSI.

Tank Size Considerations

In addition to air pressure and airflow, the size of the air compressor's tank is another vital factor. The tank size determines how long you can use the impact wrench continuously without needing to switch on the motor. Larger tanks provide a greater volume of air, resulting in extended usage time.

As a rule of thumb, it is recommended to choose an air compressor with a tank size that is at least 5 to 6 times the airflow requirement of the impact wrench. For instance, if your impact wrench requires 5 CFM, opt for an air compressor with a tank capacity of 25 to 30 litres (6-8 gallons). This will allow you to use the impact wrench for about an hour or an hour and a half without interruption.

However, it's important to note that these are just recommendations. If you plan to use multiple tools simultaneously or have a crew working on several vehicles, investing in a larger industrial air compressor with a higher airflow capacity and a bigger tank size will be more beneficial.

Air compressor duty cycle

When choosing an air compressor for an impact wrench, there are several factors to consider, such as the size of the wrench, portability, and whether the compressor is oil-free or lubricated. However, one crucial aspect that should not be overlooked is the duty cycle.

The duty cycle of an air compressor is a measure of how long the compressor can run versus how long it needs to rest, indicating the overall heaviness of the motor's duty. It is usually not included in the product listing by manufacturers or retailers, making it challenging to find on retail or manufacturer websites. The standard for testing the duty cycle is typically at a controlled temperature of 72° F and a pressure of 100 PSI.

For example, a 30% duty cycle compressor can handle 20 minutes of use and then requires a 40-minute rest period. A 100% duty cycle compressor, on the other hand, can run continuously without any rest and is typically oil-lubricated with larger, more durable parts. While these compressors can run all the time, manufacturers recommend a 50% duty cycle to prolong the motor's life.

A 75% duty cycle compressor can run for 45 minutes and rest for 15 minutes, making it a good choice for professionals or those using air tools that demand a lot of air (higher CFM output). A 50% duty cycle compressor, on the other hand, can run for 30 minutes but will need an equal amount of rest time, making it less suitable for higher-demand air tools.

If you plan to use your impact wrench frequently or require continuous airflow, choosing a compressor with an appropriate duty cycle becomes essential. A higher duty cycle will ensure that your compressor can keep up with the demands of your impact wrench without frequent breaks to recharge.

Choosing the Right Duty Cycle:

When selecting an air compressor, it's important to match its duty cycle to the airflow requirements of your impact wrench. A higher duty cycle will provide more airflow and reduce the need for frequent breaks. However, it's also crucial to consider the size of your impact wrench. For example, a 1/2-inch impact wrench requires a compressor that delivers at least 5 CFM at 90 PSI, while a 3/4-inch wrench needs 7 CFM at 90 PSI.

Additionally, if you plan to use your compressor with various tools, portability may be a factor. Larger compressors tend to have higher duty cycles and CFM output but are also more expensive and heavier, making them less portable. Smaller, portable compressors typically have duty cycles of around 50% and are more affordable, but they may not be suitable for heavy-duty or continuous use.

In conclusion, when choosing an air compressor for your impact wrench, consider the duty cycle rating to ensure it matches the airflow demands of your wrench and your intended usage patterns. A higher duty cycle will provide more airflow and reduce downtime, but it may also increase the cost and weight of the compressor. By selecting the right duty cycle, you can improve the performance and longevity of your compressor.

Air tool requirements

Air tools such as impact wrenches, drills, and grinders operate using high-pressure compressed air. An electric motor compresses air and stores it in a metal tank, and a pressure regulator controls the amount of air pressure the tank outputs.

When choosing an air compressor for an impact wrench, there are several factors to consider:

CFM (Cubic Feet per Minute)

The higher the CFM, the more air the machine can move per minute. Impact wrenches are intermittent air tools, using air in short bursts. While they don't need as much CFM as continuous-running machines, they require more CFM than a nail gun. It's recommended to purchase the highest CFM you can to ensure you have enough air to complete the job.

Tank Size

The impact wrench will use air from the tank, and the pump will replace it based on its CFM rate. If you use the air faster than the compressor can replace it, you will need to take breaks to let it recharge. If you use your impact wrench frequently or the compressor is not very strong, a larger tank is recommended.

PSI (Pounds per Square Inch)

Some machines allow you to adjust the PSI available from the hose, which may be a desirable feature if you plan to use your compressor for other tools. You can make adjustments through a regulator, so ensure your model has a durable and adjustable regulator.

Weight and Portability

If you plan to use your compressor with other tools, consider the weight and portability of the unit. Many compressors have wheels, but not all.

Drain Valve

A good drain valve is important for removing condensation from the tank to prevent rust and corrosion. Look for a drain valve that is easy to use and located at or near the bottom of the tank.

Noise Levels

Air compressors and air tools are loud machines, so it's important to consider the noise levels, especially if you have neighbours nearby or want to be able to carry on a conversation while the machine is running.

Airflow and Drive Size

Air impact wrenches are available in four common drive sizes: 3/8", 1/2", 3/4", and 1". Wrenches with different drive sizes have different airflow requirements, which are measured in CFM. Here are the typical CFM ratings for different drive sizes:

3/8" – 3 CFM @ 90 psi

1/2" – 4-5 CFM @ 90 psi

3/4" – 7 CFM @ 90 psi

1" – 8-10 CFM @ 90 psi

Tank Size Calculation

The size of the air compressor's tank determines how long you can use the impact wrench continuously without switching on the motor. As a rule of thumb, the tank size should be at least 5 to 6 times the airflow requirement of the tool.

Air Compressor Size

If you have a small garage or workshop with limited space, a small air compressor is a better choice.

Continuous vs Intermittent Use

Consider how you will use your tools. If you use your impact wrench for extended periods, you will need to calculate your air compressor's CFM requirements on a 100% duty cycle. Intermittent use may require a less powerful but more cost-effective compressor.

Multiple Tools

If you plan to use multiple tools simultaneously, you will need to add the individual CFM ratings of each tool to determine your compressor's total CFM requirement.

Air Compressor CFM Chart

To operate some of the most common tools at peak performance, refer to an air compressor CFM chart to determine the air pressure required for specific applications.

Frequently asked questions