July 13, 2020

Die Grinder vs Angle Grinder: Which One Should You Get?

die grinder vs angle grinder

In the following article, we are going to try and solve the die grinder vs angle grinder issue. Even if they are both grinders, they are very different tools. Your decision should be based on what you are planning to do.

The short answer is the following: you should get a die grinder if you need a versatile tool to do precise work; on the other hand, you should get an angle grinder if you are planning on doing a lot of heavy-duty work (for example cutting thick metal or grinding larger surfaces).

Now let’s dive into it: first, I’m gonna present you both tools, then we are going to talk about the main differences between the two. Finally, once the differences are clear, we are going to make a decision.

Angle Grinder Description and Applications

die grinder vs angle grinder

Angle grinders are very simple tools. They consist of a motor that rotates a spinning head mounted at a right-angle (hence the name, angle grinder). On the head there’s an attachment mounted, which will differ depending on the job:  it can be a cutting disc, a grinding disc, a wire brush wheel (just to name a few).  Angle grinders come in different dimensions: small models are suited for quick cuts and light jobs, while big ones are commonly used for heavy-duty work. They are used for a variety of applications. Here there are a few examples.

  • Cutting: angle grinders make good use of their power when used for rough cuts through steel bars, thick metal, etc. You can also cut tiles with the right blade.
  • Grinding: you can grind metal to remove rust or paint off its surface. Another possible application is grinding plaster or mortar off brick walls.
  • Polishing: with the right attachment, you can also use this tool for polishing activities over a variety of materials, from metal to wood. You can get very smooth surfaces in a short period of time.  Under the right circumstances, you could also use an angle grinder for polishing your car.
  • Sanding: with the right abrasive flap disc, you could also sand wood. For big surfaces, I would recommend getting a specific tool for the job, since it’s very easy to leave indents if the surface is wider than the grinder’s disc.
  • Sharpening: another thing you can do is sharpening your tools. You need to be careful, though: it’s very easy to ruin them if you let the grinder go too deep.

Die Grinder Description and Applications

die grinder in action
Photo: boschtools.com

Die grinders are the most powerful member of the rotary tools’ family. The name is due to one of their first applications: machining the shape of dies used in manufacturing industries. Their design is simple: they consist of a spinning head located at one end of the tool. Some models have it mounted at a right angle, to ease operations in narrow spaces; other ones have a flexible shaft to facilitate the use and for comfort reasons. The number of things you can do with this tool is vast. Let’s name a few:

  • Cutting: with the right cut-off wheel, you can make precise cuts through a variety of materials, like metal, wood, and plastic.
  • Grinding: unlike the angle grinder, this tool lets you grind in narrow spaces and different angles without problems. You can grind down weld to give them a better look, for example.
  • Sanding: with the right abrasive wheel, you can sand down tough spots on your woodworking project that you couldn’t reach with a traditional sander.
  • Honing: traditionally, die grinders were used for the finishing of cylinders for internal combustion engines and other cylindrical applications.
  • Machining: this applies to a variety of materials, from metal (machining of dies, molds, etc) to wood (carving activities). This tool is great for this type of activity where there’s a combination of flat at curved surfaces involved. In fact, you need to work at different angles to grind them into the right shape.

Die Grinder vs Angle Grinder: The Differences

Now let’s dive into the core of the matter, i.e. the differences between the two pieces of equipment. This is the main thing to consider when making a decision.

Tool Design

First, let’s speak about how these tools are designed. The angle grinder head is positioned at a right-angle. It comes with a side handle on top of it, which makes it easier and safer to use. The disc/wheel is protected by a safety guard, that protects you from sparks, dust, etc.

On the other hand, the die grinder’s head is usually positioned parallel to the body of the tool. Certain models have it positioned perpendicular to the tool, in a way that is similar to an angle grinder. With this configuration, you can access tight spots that would be unreachable otherwise. There’s no side handle, so you have to grab the body with both hands to operate. There’s no safety guard either (even if you can buy it separately).

While we are here speaking about design, let’s spend a couple of words on the power source of these tools. An angle grinder is an electric tool, which comes either corded or cordless (battery-powered). Die grinders can be electric or pneumatic. Air-powered models are obviously corded, while electric models can be either corded or cordless. Keep in mind that the pneumatic version of the tool is more powerful.

Power and Speed

Now let’s talk about power and speed output. We need to make a distinction between small and big angle grinders.

Small 4 1/2 inch angle grinders come with a 5-6 amp,  around 1 hp (horsepower) motor that rotates at 10,000-12,000 rpm (revolutions per minute). Bigger models (with a 7-inch blade) have larger motors. I checked the specs on some models, and on average they come with a 13-15 amp, 4-5 hp motor that rotates at 6,000-8,000 rpm. So the bigger the motor, the more horsepower and less speed it delivers. Which is expectable, since more torque means less speed and vice-versa.

Let’s see the power and speed specs for die grinders. Their motors are less powerful than angle grinders’: on average, they come with less than 1 HP (more like 0.3-0.5 HP). This means that they rotate at a much higher speed: we are talking about 20,000 to 30,000 rpm. So they are comparable to small angle grinders in terms of power, but they spin at a much higher rate.

These differences impact the kind of jobs each tool can do. Big, powerful angle grinders are suited for heavy-duty work. Their power and dimensions limit their precision, since they can’t fit in tight spots and they are harder to control. On the other hand, die grinders are perfect for precise, lightweight kind of activities because they are much more manageable. So each one serves a certain duty. Keep that in mind going forward.

Tool Size (Dimensions and Weight)

As we already noticed, angle grinders come in different sizes. Small ones come with a 4 1/2 inches blade. On average, they weigh 4-5 lbs and they are 10-15 inches long. On the other hand, bigger 7-inch blade models weigh around 15 lbs and they are 20 to 25 inches long.

Die grinders are lighter: they weigh around 3.5 – 4 lbs, while they are 15 to 20 inches long on average. There are also small air models available, weighing only 1 lb while being 7 inches long.

So as you can see, die grinders are similar to small angle grinders weight-wise while being in the middle of the two length-wise.

This was expectable. Bigger motors require more space and are much heavier. This means that a die grinder is more comfortable to use that a 7-inch angle grinder because it’s easier to control (it’s less powerful) and it’s lighter. I would say these advantages even out against a 4 1/2 inch angle grinder. The latter is a little bit more powerful, but it comes with a handle that makes it easier to use.

Attachments

When it comes to attachments, angle grinders are pretty straight forward. Common ones are:

  • Discs (these can either be cut-off discs, abrasive disc for grinding purposes, sanding disc);
  • Stones (I am referring to grinding stones for concrete here);
  • Pads (for polishing activities);
  • Wheels (wire brush wheels for dust removal is a good example).

Let’s talk about die grinders not. If you think of a possible operation to do, there’s probably a die grinder attachment for it. This is just another confirmation of how versatile this tool is. Here you have some of them (I won’t make an exhaustive list here since it would take an entire article for itself):

  • Cut-off wheels for precise cutting activities;
  • For sanding purposes, you can get sanding drums or sanding flap wheels;
  • For polishing, there are cloth or fibers wheels/drums available;
  • Drill bits (yeah, you can use this tool like a drill too);
  • Small endmills for machining stuff (metal and wood);
  • Burrs (also known as rotary files) for grinding down surplus material (for example in welding).

Type and Size of Surface They Can Work On

At this point in the article it should be obvious, but let’s make it more clear.

Angle grinders are suited to work on flat surfaces or externally curved surfaces. This depends on the dimension of the tool and the design of the attachments (which are flat). They perform well on small and big surfaces, and you can get a lot on work done quickly. On the other hand, die grinders can be used on either flat or curved surfaces. They perform very well on internally curved surfaces. If you need to enlarge a hole (or remove rust) in a piece made of metal, a die grinder is pretty much the only tool that you can use to do it. Unlike angle grinders, die grinders don’t perform so well on big surfaces. Their bits are too small to get the job done in a reasonable time.

What do Users Think?

As I always do when comparing stuff, I like to read some comments on the tools to view the matter from another angle. This way, I’m sure that I’m unbiased when making the final decision. Here’s what I found:

  • A possible downside of the high speed die grinders rotate at is that wheels and discs will wear out very fast. A good idea is to always have a bunch of them available in order to be able to finish the job;
  • Small angle grinders are much more versatile than one could expect and are very comfortable to use;
  • Speed control might be hard on air die grinders because the air control paddle tends to be quite stiff. So it’s either zero or full speed. A workaround might be placing a buffer behind the paddle to regulate it;
  • Big angle grinders require a lot of strength to be held in your hands. So if you are planning to use it for a long period of time, it might be a good idea to look for the lightest models available.
  • A lot of users are surprised about how die grinders are inexpensive tools.

Conclusions: Which One Should I Get?

After making all these observations, let’s settle the die grinder vs angle grinder challenge.

You should get an angle grinder in the following cases:

  • The plan is to do a lot of cutting, especially on hard materials. In this case, I recommend a 7-inch angle grinder ;
  • You want to operate on big surfaces, where you need to get a lot of heavy work done fast and you don’t care about precision, to a certain extent.
  • You won’t need to operate in tight spots.

On the other hand, you should get a die grinder for the following reasons:

  • You are planning on doing a wide variety of activities on different materials (from metal to wood);
  • You want to work on small surfaces with a high degree of precision. For example, you might be interested in carving wood;
  • You want a versatile tool that can accept a variety of bits.

I hope this article was somewhat helpful. As you learned, the best way to make a decision when getting a tool is by asking yourself what kind of projects you need it for. If you have that very clear in your mind, making a pondered purchase should be easy.