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 into 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 an Die Grinder
- Intermittent or Continuous Die Grinder Use?
- What CFM Rating Die Grinder Have You Bought or Are You Considering Buying?
- What Pressure Rating Die Grinder Have You Bought or Are You Considering Buying?
- Air Compressor Duty Cycle
- CFM Delivery Capability of the Air Compressor
- Air Compressor Tank Size (Compressed Air Storage Capacity)
- Distance You’ll be Using the Die Grinder From the Compressor (Hose Length)
- FAQs (Frequently Asked Questions)
- Reader Questions and Responses
Key Considerations – Choosing an Air Compressor for an Die Grinder
There a 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)
- 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 require continuous or intermittent use out of your compressor for your die grinders 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 it’s 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 it’s “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 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 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, how they’re expressed and calculated, you should read my article on air compressor duty cycles.
Here’s another example of a product manual which 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 Cyle 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 which 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 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 which is rated 5.30 CFM – and though product manual does not describes 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 hours 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 only required being 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 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 which 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)
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 it’s duty cycle.
Therefore an 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 an 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 on the capacity needed based on a die grinders 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)
A mini die grinder can require anything between 3-5 CFM on average @ 90 PSI whilst a normal die grinder can reach up to 10-15 CFM on average @ 90 PSI.
Depending on the CFM requirements of the die grinder, and whether you wish to conduct intermittent or continuous use of the tool, the size of the air compressor needed will vary. An example: a 10 CFM air compressor with a 50% duty cycle could provide continuous use to die grinders with average CFM’s below 5 CFM and intermittent use to die grinders with average CFM’s up to 10 CFM.
Reader Questions and Responses
Is my compressor big enough to run my die grinder?
by Bret Duster
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.
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.
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!