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Die Grinders Explained – What Are They, Different Types, What Are They Used For & Buying Guide

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Die grinders are one of the more versatile but often underappreciated tools available in today’s market. This article will provide you with all the relevant information about die grinders, the different types, a buying guide, and examples of some of the best available on Amazon!

Table of Contents

What is a Die Grinder?

A die grinder is a small, handheld power tool that contains a rotating spindle where a collet holds the cutting bit. The grinding bit rotates at a very high speed and is used to remove material from the workpiece. Die grinders generally look quite similar to other rotary tools and tend to be powered by either compressed air or electricity.

A die grinder with the right attachment on the end will enable you to polish, sand, cut, grind, or hone a wide variety of materials. Therefore, this makes a die grinder a very useful tool in many different circumstances. Some of the most popular die grinder bits include:

  • Grinding bits
  • Carbide burr
  • Grindstone bits
  • Polishing wheels
  • Wood cutting wheels
  • Metal cutting wheels
  • Sanding wheels
  • Wire wheels
Die grinder by Ingersoll Rand
Die grinder by Ingersoll Rand

How a Die Grinder Works

A die grinder has a rotating spindle where a sleeve/chuck is used to tighten a bit to the end. For example, you could insert a sanding bit that will enable you to smooth or remove material from your wood project by rotating at a very high speed. Now there are several different sanding bits, so the bit you use will vary depending on the need.

What is a Die Grinder Used For?

When a die grinder is combined with the right attachment, it can do a wide variety of tasks. Die grinders are primarily designed to work with metal (specifically for Tool and Die making), but they can also be used on more sensitive materials like wood and plastic. The most common uses include:

  • Polishing metal
  • Reworking dies
  • Rust removal
  • Smoothing out surfaces
  • Sharpening blades

Polishing Metal

Metal, especially stainless steel, always looks far better after it has been polished. Regardless of the metal object itself, anything metal will look better after you have given it a thorough polishing. However, the task can become hard work if you have a huge object that needs polishing.

Polishing a car, for example, can end up being a really long, tiring process. With a die grinder, polishing even vast surfaces can be a lot quicker and easy. Since the rotary polishing bits are round in cross-section, die grinders are perfect for polishing holes and curved surfaces.

Reworking Dies

Have you wondered how a die grinder got its name? The die grinder got its name from the original purpose for which it was developed: grinding the dies used in tooling. These include metal stamping dies, plastic molds, die-casting dies, forging dies, etc.

It was common for die makers to grind and match the profiles of the mating parts manually before the arrival of CNC milling, EDM Spark Erosion, EDM Wirecut, and other high-precision machines. The die grinder is the best tool for the job since it is small and easy to maneuver. Today toolmakers use die grinders for a variety of reworking projects, such as deburring, chamfering, polishing, grinding and matching the welded surface, etc.

Rust Removal

Rust can be deadly and difficult to remove. If it is not removed, it could destroy anything it infects. If you catch the rust early, you will be able to remove it from the metal. A die grinder can be handy for getting rid of stubborn, stuck-on rust. It will allow you to do it very quickly, which is certainly useful if you have a lot of rust that needs to be removed.

Smoothing Out Surfaces

You often have to smooth out the final product after finishing something like a woodworking project, which can be tricky. If you don’t smooth it out right you are running the risk of ruining the project. A die grinder with the correct attachment can be used to smooth out a wide variety of different materials such as metal, hardened steel, wood, and more.

If you do metalworking, then you know how annoying and messy the edges of welds can be. A die grinder can easily remove the excess welds for a far smoother and cleaner looking metalwork. This is certainly a must-have tool if you do a lot of welding or metalwork of any kind.

You may wonder why not use an angle grinder instead of die grinder? And we’ll get into their comparison a bit further down the page but the main reason is because die grinders are more precise and you have better control over the tool.

An angle grinder is a large tool that is used for removing the surplus amount of material fast. They should be handled with care and are generally not ideal for precision works. Besides, angle grinders are certainly not suitable to grind inside small and intricate holes.

Sharpening Blades

Many die grinders are capable of being equipped with a blade sharpening attachment, which will allow you to sharpen a wide array of blades. You can use them for knives, hatchets, axes, and pretty much any other kind of blade that you can think of. They are great for those who don’t own a proper grindstone, but who still want to keep their blades nice and sharp.

Types of Die Grinder

When it comes to the types of die grinders that are available, we can categorize them as their design or their power source. We’ll discuss pneumatic die grinders vs angle grinders in the next section, so here we will focus on the power sources. Die grinders are available as either:

  • Electric
  • Pneumatic

Electric Die Grinders

Electric die grinders need to be plugged into an electric outlet to work. They are typically less powerful when compared with their pneumatic counterparts, but the benefit they have is being lighter and a lot quicker.

It should also be noted that because they tend to be less powerful, electric die grinders can use some unique bits that can’t be used on the more powerful pneumatic die grinders, which may be admirable.

There are two versions of electric grinders available; corded and cordless. The cordless version runs on rechargeable batteries but this comes with unwanted bulkiness which may limit your maneuverability in tight spaces. However, of course, a massive benefit is their portability. If portability is more important for you, then the cordless tool is your best friend.

Pneumatic Die Grinders

A pneumatic die grinder is the better option for you if you want power and raw torque. They are mighty powerful because they harness the power of compressed air. A pneumatic die grinder can be a lifesaver when you have large projects as they work fast and efficiently.

Pneumatic die grinders tend to be pretty inexpensive due to their popularity, and so, if you are on a budget and already own an air compressor, then it’s a no-brainer, this is the best option for you.

However, there are of course some drawbacks with pneumatic die grinders. The fact that you have to lug around an air compressor and all that comes with it, typically the hose around your workspace, when using the tool makes it very cumbersome to use, especially if you are working in confined spaces.

If you don’t already own an air compressor, then getting one that is also compatible with your tool can become both expensive and a hassle. Finally, because of how powerful they are, pneumatic die grinders probably aren’t the best option for jobs that require a lot of precision and a soft touch.

Advantages of Pneumatic Die Grinders

Circling back to the advantages of pneumatic die grinders and what they offer compared to electric die grinders. The advantages can be summarized as:

  • No risk of electric shock
  • Increased productivity
  • Superior ergonomics and power to weight ratio
  • High performance in harsh environments
  • Ease of servicing and sustainability

No Risk of Electric Shock

Die grinders of all varieties are frequently used in environments where moisture, conductive materials, and flammable liquids are present. Damaged cords and wires pose a risk to operator safety resulting from electrical shock.

In contrast, air tools require no electricity, and their rotary vane air motors generate no sparks, allowing them to, therefore, be able to create a safer work environment which decreases the likelihood of violating any OSHA legislations.

To put it simply, air tools are safer than electric tools because an air hose will never emit a spark and can safely be used in wet conditions.

Superior Ergonomics and Power to Weight Ratio

Pneumatic grinders offer a far better power-to-weight ratio than electric grinders. They are able to produce more horsepower in a smaller and lighter package.

Increased Productivity

If increasing your worker output is a priority for your operation, then pneumatic grinders can help you meet these goals.

High Performance in Harsh Environments

Electric motors have a rated duty cycle, which must be respected. Without periodic rest, the performance of the tool will be diminished by the heat generated by the motor and may even lead to premature tool failure. Electric die grinders generally need a minute rest for every 4 minutes of running.

In contrast, air-powered die grinders have a 100% duty cycle, meaning they are designed to run 24 hours a day 7 days a week when used with a filter regulator lubricator. Air tool housings are generally made of aluminum or steel, rather than ABS plastic which makes them far more resistant to the impact of repeated drops.

Ease of Servicing and Sustainability

An industrial-grade grinder is not a disposable piece of equipment and doesn’t immediately end up in the landfill like a “disposable” commercial electric grinder. Pneumatic grinders can be tuned up and be periodically rebuilt many times over and serviced a lot easier.

Die Grinder vs Angle Grinder

Straight die grinders are just regular die grinders. They are completely straight and almost resemble a sort of large screwdriver. Right-angle die grinders work the same as straight die grinders, except for the fact that the bit on a right-angle die grinder is perpendicular to the body.

As we’ve covered regular die grinders extensively in this article, let’s take a look at angle grinders and then compare the two.

Angle Grinder

A right-angle grinder, also referred to as a disc sander or a side grinder, is a tool whose name describes how the tool looks; the head of the tool is at a 90-degree angle from the shaft of the tool. It is a handheld power tool that has a rotating disc approximately 4 to 5 inches in diameter with its main use is for grinding and polishing.

Many angle grinders are electric, either corded or cordless, but there are pneumatic angle grinders available too. Some larger-scale angle grinders may even be gas-powered.

The majority of angle grinders weigh anywhere from 5 to 10 pounds, approximately double that of a regular straight die grinder. The motors range from 3 to 4 amps up to 7 or 8 amps and they can produce RPM over 10,000.

As with the die grinder, there are many uses for the angle grinder. Although its primary function is polishing and grinding, they can be also be applied to a variety of materials and projects. It also can cut and sand if you use the appropriate disc.

With the correct disc attached to the angle grinder, you will be able to complete any task you wish. For example, if you need to cut masonry, there is a diamond blade. For metal, there are metal cutoff discs, and for cleaning rust off of metal, there is a wire cup brush. If you have any issue or task, there is a disc you can attach to help with the problem.

Die Grinder vs Angle Grinder: Which One to Use?

There aren’t actually any pros or cons to the type of die grinder that you pick. Straight die grinders and right angle die grinders work the exact same. So, it comes down to the kind of work you do.

A right-angle die grinder is used to work in tight spaces where the straight grinders cannot fit it. The straight version of the tool along with the cutting bit may be too long to work inside the machine and automobile parts.

Die grinders are a very useful tool. They can be used on a variety of projects, both for the professional and the DIY’er. The die grinder is smaller and more manageable than the angle grinder and can in many cases be used with one hand. It is lightweight and easy to maneuver. The small bits allow the user to get into tight spots that would not otherwise be possible with just your fingers.

An electric angle die grinder also have many uses and are just as versatile. They are larger than the die grinder and will require the use of both of your hands to keep it under control. They are better suited for the larger projects that you have around your house or for the professional.

Die GrinderAngle Grinder
Sanding small wood projectsSanding larger wood projects
Making precision cutsMaking general cuts
Polishing small itemsPolishing larger areas
Used for delicate cutsUse for autobody work
Intricate tile cutsCutting cinderblock
Die Grinder vs Angle Grinder Uses Table

Pneumatic Die Grinders Available on Amazon

I have picked out some of the best pneumatic die grinder readily available on Amazon for purchase. First up is this Chicago Pneumatic die grinder capable of provided 27,000 RPM, ideal for moldings and generally high-speed polishing and grinding, with a built-in air regulator.

Next up is this Chicago Pneumatic angle die grinder capable of providing 22,500 RPM, ideal for limited space applications and built with a robust aluminum alloy body.

This Ingersol Rand die grinder is an amazon choice capable of powering through difficult jobs with 27,000 RPM, suitable for grinding, cutting, polishing and more. Its contoured grip gives greater comfort and control and its ergonomic design delivers exceptional torque precision, as well as increased productivity and safety.

Finally, we have this DeWalt die grinder, capable of providing 25,000 RPM and boasting terrific reviews by users.

FAQs (Frequently Asked Questions)

What is a pneumatic die grinder?

A pneumatic die grinder is a die grinder powered by compressed air coming from an air compressor. They are the better option for you if you want shear torque. A pneumatic die grinder can be a lifesaver when you have large projects as they are able to work fast and efficiently.

What is the difference between a die grinder and angle grinder?

Die grinders and angle grinders work in the same way, but the key difference is in the work that they’re capable of doing. Die grinders are generally suited to sanding small wood projects, making precision cuts, polishing small items, delicate cuts and intricate tile cuts. On the contrary, angle grinders are generally used for sanding larger wood projects, making general cuts, polishing larger areas, autobody work and cutting cinderblock.

What is the difference between a pneumatic grinder and an electric grinder?

The evident difference between a pneumatic grinder and electric grinder is the power source. While electric grinders use electricity to operate, either corded or cordless, pneumatic grinders are typically powered by compressed air coming from an air compressor. Pneumatic grinders offer the advantages of no risk of electric shock, increased productivity, superior ergonomics and power to weight ratio, higher performance in harsh environments, and
ease of servicing and sustainability.

Why is it called a die grinder?

The die grinder got its name from the original purpose for which it was developed, to grind the dies used in tooling such as metal stamping dies, plastic molds, die-casting dies, forging dies, etc.

If you’re wondering how to plumb an air compressor setup, visit our guide!

If you have any questions about die grinders, please leave a comment below, with a photo if applicable, so that someone can help you!

By Aidan Weeks

A passionate Mechanical Engineer with endless enthusiasm for fluid power - building off the back of over 18 years of high quality contribution and discussion stimulated by Bill Wade here at About Air Compressors. With both practical and theoretical experience in pneumatics and hydraulics, I'm putting my knowledge to work - and working my grey-matter through my research, assistance and publishing work here at About Air Compressors. Feel free to reach out any time! P.S. A HUGE shout out to Doug who really offers such great value to all visitors to About Air Compressors - once again, feeling like I'm standing on the shoulders of GIANTS by getting to work alongside such a great community

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