What Size Air Compressor Do I Need for a Die Grinder?

If you have a die grinder or you’re looking to purchase one for a project at home or in the workshop, you may now be wondering what size air compressor you need to run this die grinder.

This page will serve as a guide to what size air compressor you need for your die grinder by presenting all the key considerations and relevant information!

Table of Contents

• Key Considerations – Choosing an Air Compressor for a Die Grinder
• FAQs (Frequently Asked Questions)
• Reader Questions & Responses

Key Considerations – Choosing an Air Compressor for a Die Grinder

There are a few very key considerations you must look at when finding an air compressor suitable for a die grinder and these are:

• Use cycle – Continuous vs Intermittent Use
• CFM requirements & CFM rating of the die grinder
• Pressure requirements of the die grinder
• Duty Cycle of the air compressor
• CFM delivery capability of the air compressor
• Air compressor tank size (compressed air storage capacity)
• The distance you’ll be using the die grinder from the compressor (hose length)

Intermittent or Continuous Die Grinder Use?

The first, and very important consideration, is whether you require continuous or intermittent use out of your compressor for your die grinder’s work.

If you only require intermittent use of your die grinder then a small compressor may provide enough to power it but if you require continuous use then the compressor has to have the discharge capacity that the die grinder demands.

A typical use cycle on a die grinder in a non-assembly line environment is likely to be far less than 50% of the time drawing its full CFM rating.

What CFM Rating Die Grinder Have You Bought or Are You Considering Buying?

Die grinders come with CFM ratings, often expressed as SCFM ratings (as it’s a standardized unit). This rating can also be expressed as its “Air Consumption”. I will now provide you with some examples of small, medium, and large die grinders.

Example of a Small Die Grinder

Here’s an example of a small die grinder, this Workpad 3.0 CFM mini die grinder is equipped with 1/4″ and 1/8″ collets.

• Collet size: 1/4″, 1/8″
• Free speed: 25,000 RPM
• CFM: 3.0

Example of a Medium Die Grinder

This 1/4″ 20,000 RPM Ingersoll Rand air die grinder is a medium-sized offering that provides an average air consumption of 5 CFM.

• Collet size: 1/4″
• Free speed: 20,000 RPM
• CFM: 6.0

Example of a Large Die Grinder

Here’s an example of a larger 1/4″ 24,000 RPM Chicago Pneumatic die grinder. It is rated at an average of 10.5 CFM.

• Collet size: 1/4″
• Free speed: 24,000 RPM
• CFM: 10.5

What Pressure Rating Die Grinder Have You Bought or Are You Considering Buying?

All air tools, with air die grinders being no exception, have a recommended operating pressure.

The Workpad mini air die grinder as an example has a stated recommended operating pressure of 90 PSI as per the technical specifications on the Amazon listing. This is a commonly recommended pressure for many air tools as can be validated by the other two die grinder ratings.

The Ingersoll Rand die grinders manual states a recommended tool pressure of 90 PSI.

And, the Chicago Pneumatic’s die grinders manual states that you should supply the tool with 90 PSI of clean, dry air and not exceed this.

Air Compressor Duty Cycle

The typical duty cycle of an air compressor is 50% more often than not, as can be seen in this Craftsman 919 manual. It states that the maximum compressor pumping time per hour is 30 minutes (a 50% duty cycle).

If you want to know more about air compressor duty cycles, and how they’re expressed and calculated, you should read my article on air compressor duty cycles.

Here’s another example of a product manual that describes the duty cycle of a compressor in these terms:

“INTERMITTENT DUTY FORMULA

Pump-up time should not ordinarily exceed thirty (30) minutes or be less than ten (10) minutes. Shutdown periods between cycles of operation should be at least equal to the pump-up time. Note: When the compressor is regulated by constant speed control, the shutdown period is the time the compressor is operating unloaded.“

This is describing a 50% Duty Cycle.

CFM Delivery Capability of the Air Compressor

CFM ratings of air compressors tend to be based on the output of the air compressor pump.

However, to understand what ability the air compressor has to deliver CFM continuously you need to multiply the CFM rating by the Duty Cycle percentage.

So an Air Compressor CFM rating of 10 CFM with a 50% Duty Cycle would have the ability to deliver:

10 CFM * 50% = 5 CFM

Example of an Air Compressor Suitable for a Small Die Grinders

Here’s an example of a small air compressor that delivers 2.4 CFM – and the product manual describes what would be determined as a 50% duty cycle. Therefore the compressor would actually deliver 1.2 CFM (2.4 CFM * 50%).

This would be suitable for a small die grinder given that you only require intermittent use. But, this compressor wouldn’t be suitable for continuous use on any of the die grinders presented in this article.

The small Workpad die grinder requires 3 CFM, if the use was intermittent and only needed 25% of the time (15 minutes per hour), then the grinder only requires 0.75 CFM (3 * 25%). Therefore, this compressor would be capable of providing that that CFM.

However, if you are required to use the die grinder on a 50% duty cycle, the grinder would require 1.5 CFM (4 * 50%). The air compressor running at its recommended 50% duty cycle would not be able to provide the necessary amount of CFM required by the die grinder.

It would only be able to provide the 1.5 CFM requirement if you overworked the compressor by running it on a 90-100% duty cycle which is strongly not recommended.

Example of an Air Compressor Suitable for a Medium Die Grinders

Here’s an example of an air compressor that is rated 5.30 CFM – and though the product manual does not describe the duty cycle, a customer Q&A response has declared that the compressor has a 70/30 (70%) duty cycle. What would be determined as 20-25 minutes rest after each hour’s use.

Therefore, this air compressor is actually capable of delivering 3.71 CFM (5.3 * 70%). This is just about sized for continuous use of the 3 CFM Workpad die grinder.

However, if the die grinder is only required to be used intermittently (50% of the time) then this compressor is suitable for not only the Chicago Pneumatic die grinder but also the medium Ingersoll Rand die grinder (6 CFM * 50% = 3 CFM).

If you were to obtain a die grinder with a CFM of below 3.71 CFM then this compressor would be capable of delivering continuous use to that tool.

Example of a Large Air Compressor Suitable for Large Die Grinders

Here’s an example of a large Air compressor, the Ingersoll-Rand 8 Gallon twin compressor capable of delivering 11.5 CFM with a 100% continuous duty cycle.

This compressor is suitable for providing continuous use to the small, medium, or large die grinders provided. It could even power both the small Workpad and medium Ingersoll Rand die grinders simultaneously.

If this compressor were to have a 50% duty cycle however and provide 5.75 CFM (11.5 * 50%) it would only be able to power the small Workpad die grinder continuously.

It would consequently no longer be able to provide continuous use to the medium or large die grinder when working with a 50% duty cycle, but instead could work intermittently if the Ingersoll rand tool required 3 CFM (6 * 50%) and the Chicago Pneumatic tool required 5.25 CFM (10.5 * 50%).

Example of an Extra Large Air Compressor Suitable for Powering Multiple Die Grinders Simultaneously

Here’s an example of an industrial air compressor that delivers 38 CFM – and the product manual describes what would be determined as a 100% duty cycle.

This is a stationary compressor, that has a continuous run & automatic stop/start feature, making it capable of powering the small, medium and large die grinders continuously and all of them at once!!

Air Compressor Tank Size (Compressed Air Storage Capacity)

The tank size will determine how much air is available to be drawn down at any time. This is also a key enabler in keeping a compressor within its duty cycle.

Therefore a 10 CFM compressor with a 50% Duty Cycle can be used to run an air die grinder that’s rated at 10 CFM – if used intermittently with a sufficiently large air tank.

To keep a compressor running for at least 10 minutes with a die grinder consuming 10 Cubic Feet of air per minute for 50% of the time, the storage capacity would be:

10 CFM * 10 minutes * 50% = 50 Cubic Feet of air (at atmospheric pressure (15PSI))

As atmospheric pressure is 15 PSI and the output pressure is 90 PSI and pressure and volume are inversely proportional 15 PSI / 90 PSI = 6

Therefore, you need 1/6th the volume of air at 90 PSI

50 Cubic Feet * 1/6th = 8.3 Cubic Feet

8.3 Cubic Feet = 236 Litres

This is an example to give you a basic idea of the capacity needed, based on a die grinder’s minimum running time of 10 minutes.

Distance You’ll Be Using the Die Grinder From the Compressor (Hose Length)

Long hoses will result in pressure drop. Though I could not find any recommendations in any of the Die Grinder manuals presented in this article. It can be generally recommended that the hose should be just long enough to serve the working area.

If you have a hose over 25 feet long then you should compensate for the pressure drop to ensure that your tool is receiving the correct operating pressure.

For further information on air hoses visit our Air Compressor Hose & Tube Guide.

FAQs (Frequently Asked Questions)

Additional CFM reading:

• SCFM Vs ACFM Vs ICFM – What’s The Difference? Converting & Calculating
• Best Ways to Increase CFM On Air Compressors
• Connecting Two Air Compressors Together
• How to Calculate CFM of Air Compressors
• CFM Pipe Size Chart
• SCFM vs CFM for Air Tools & Air Compressors Guide to Compressor Ratings
• What Is CFM and What Does CFM Mean on An Air Compressor?
• Air Compressor Size For Spraying Stucco & Plaster
• Does a die grinder require low or high CFM?
• Speedaire 4B247 swapped with 2Z499 and its effect on CFM?
• 20 CFM Air Compressor – Buying, Hiring, What Can They Run?
• Air Compressors That Produce 500 CFM And Above
• CFM SCFM PSI Compressor Flow Issues
• Ingersoll Rand Type 30 model 242 HP and CFM?
• CFM rating of Black Max compressor

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Reader Questions & Responses

Is My Compressor Big Enough to Run My Die Grinder?

Question

Is my Husky/Porter Cable ‘Easy Air to Go’ 2 SCFM @ 90PSI/135max big enough to run an air tool such as a 17 SCFM die grinder. Thanks.

Response

The easy answer is…yes it will. The tougher answer is not very well and not for but a few seconds before you run out of air.

If you’re relying on your little compressor to provide enough air to use your die grinder for long periods of time… and particularly if you are in a hurry, then you are going to be disappointed.

If you’re running a die grinder that sucks 17 CFM of compressed air at 90 PSI for a production environment…that is, using it for hours at a time, then you’re going to need at least a 5HP compressor with as large a reservoir as you can afford to have sufficient air supply.

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If you have any questions regarding what size air compressor you need for a Die Grinder, please leave a comment below with a photo if applicable so that someone can help you!