Fillet vs. Chamfer: What You Need to Know

chamfer vs fillet
Jack Lie CNC machining expert

Specialize in CNC Milling, CNC Turning, 3D Printing, Urethane Casting, and Sheet Metal Fabrication Services.

Most people consider the geometric distinction between a fillet and a chamfer when making this comparison. However, the two terms are not so easily defined.

What Is the Chamfer?

A chamfer is an angled or sloping corner or edge often used to prevent damage and give a rough edge a smoother appearance. Let’s take a look at a chamfered edge to see what it looks like and learn why chamfers are used in fillet engineering on edges with a high concentration of stress.

A part with chamfer edges
A part with chamfer edges

Chamfer edges, in contrast to smooth edges, are sharp and linear and are used for mild stresses concentrated at corners because they may deform the material. This means it shouldn’t be used near edges where there’s a lot of stress. It is essential to understand the difference between a chamfered edge and a beveled edge, as well as the role of chamfer in AutoCAD, before beginning any design. A bevel is an edge sloped on top, while a chamfer is an edge that is beveled on the bottom. Both of these edges may connect with two different surfaces.

What Is the Fillet?

Fillets are the rounded sections of designs seen on the inside or outside of edges. They are often used in mechanical engineering by machinists.

A  part with fillet edges
A part with fillet edges

In mechanics, fillets may be either miter, concave, or convex. In contrast to their convex exteriors, fillets are concave on the inside. Fillets are used by engineers to lessen the stress on a component. As a result, the fillet aids in stress distribution over a wider area, therefore slowing the rate of deformation of the stressed section.

Fillet engineering is the ideal choice for machinists when the design calls for the elimination of sharp edges and the concentration of low stresses.

What Are the Chamfered Edges?

A chamfer is a form of the bevel with an acute angle. We may divide chamfer into two distinct categories in mechanical engineering:

  • The 45-degree chamfer is used to eliminate the drill burr. The chamfers prevent the bolt from protruding beyond the flat fir surface.
  • A chamfer angle of 60 degrees results in sharp edges and has little to no stress-relieving impact. They are utilized as a starting point for a screw and a bolt. Following the finishing of the pieces, chamfering is required to create a furrow, groove, or bevel.

Difference Between a Fillet and Chamfer

For better understanding, the table below concludes the differences between fillet and chamfer.

FeatureA chamfer is a beveled or angled corner on the edge of an interior or exterior part.Fillets are internal or external rounded features at the corners of a part. The inner fillets are concave and the outer fillets are convex.
Cutting toolsOnly one cutting tool can make different chamfer sizes.The cutting tool is determined by the kind of radius you require, so special one are necessary.
Machining timeFasterConsume more time than chamfer
Machining costLowRelatively high
SafetyThe sharp edges may lead to injury.It offers better safety for handling materials.
Stress concentrationThe material is easy to be deformed as it’s subjected to the stress.It spreads the stress over a larger radius and keeps the part from deformation, so it is best suited for exterior parts.

When to Use a Fillet or Chamfer?

In addition to the difficulty in discriminating between the two, machinists also have trouble deciding which one to use in any given design. Using the incorrect one might drive up production costs and compromise product quality.

Substituting a chamfer for a fillet or vice versa might reduce the part’s durability. Knowing the difference between a fillet and a chamfer can help you pick the one that works best for your design. Let’s take a step back and talk about the differences between fillet and chamfer in more depth.

Part Edges

You should round off all the corners of your components so that nobody gets hurt while you’re handling or inspecting them. The chamfer may not be the ideal choice for a component’s edge. Handling might be hazardous due to the sharp edges. You might want to consider using a fillet instead.

Outside Edges

You may employ either fillet or chamfer for your outer edges, depending on the design necessity. Simple chamfering may be used to break the sharp edges if an elegant exterior is not required. Because of this, no people will be hurt while working with the component.

However, a fillet around the corners is the way to go if you want the outside of your design to look good. However, the radius size should be taken into account. The greater the radius chosen, the better the design since a fillet with a large radius may prevent stress.

On the Hole

A fillet is not recommended if your design calls for a hole into which fasteners like screws or bolts will be pushed. That’s going to make it so the bolt or screw can’t go in easily. In this instance, you’ll want to use a chamfer. The pointed edge will facilitate easier passage of the pin down into the hole. It will also facilitate the fastening process.

It would concern the right selection of design and manufacturing process directly if you are perplexed with the concept of chamfer and fillet. But don’t worry, Runsom is here to help you and give you professional suggestions and solutions best suit your project. Upload your files and we will reply to you instantly.

How to Choose Between a Fillet and Chamfer

When it comes to deciding if their design should include a fillet or chamfer, machinists sometimes find themselves in a condition of ambiguity. If you want to prevent getting into such a state of perplexity, you should think about the points that are listed below.

Machining Time

It’s possible to use chamfer if you need to manually create a complicated design in a hurry. This is so because it is a quicker alternative to the fillet. If, however, you use computer numerical control (CNC) machining rather than the hand-operated kind, the two processes take about the same amount of time. It will just take longer to switch tools.


In terms of cost-effectiveness, a chamfer is preferable to a fillet. Because of this, a chamfer is a preferable option for you if you are working with a limited budget on your design.


If you are looking for a design that is more visually pleasing, you should go with a fillet. Fillet is often used by industrial designers rather than chamfer because it contributes to a more aesthetically pleasing design.


Filleting metal components is a better way to avoid premature corrosion than chamfering. Because it’s easier to apply a homogeneous finish, like paint, without a chamfer, it’s the preferred method. When compared to sharp edges, the part’s ability to cling to thicker coatings is greatly enhanced by the use of fillets. The increased susceptibility to rust is a result of insufficient coatings. Therefore, a fillet is necessary if you want to prevent your components from rusting too quickly.


Suppose you want the stress of your design to be distributed evenly throughout the corners. In that case, a fillet is a technique you should choose to use. This is because, in comparison to a chamfer, it distributes the stress across a wider surface area.


The purpose of the hole in your design will decide whether a fillet or chamfer is the most appropriate technique to use. If the hole is intended to be used for the insertion of a pin or for driving screws and bolts into the component, then chamfering is the superior choice.


While chamfers are more tolerant in mating components, fillets have reduced stress concentration factors and may prevent deformation. Hence, it is crucial that you be familiar with the distinction between chamfer and fillet definitions in engineering so that you can choose the most appropriate design and machining process for your project. A cost-effective, high-quality design may be achieved by weighing the merits of the chamfer, fillet, and bevel.

Count on Runsom to Create Fillet and Chamfer for Your Project

However, why bother with a design when you can outsource the design work to a professional company? Runsom is here to help. Our engineering team with years of experience in design engineering and part manufacturing will assist you to choose the right method for your machined parts, so you can rest assured that your design will be turned into physical products as per your requirements and specifications exactly. Submit your files and get started with your project with us.

Runsom is an expert in offering CNC turning, 3, 4, and 5-axis milling services. Work with Runsom, and we will return you the best result at a competitive price. We also provide a series of secondary processing options, packaging, assembly, and shipping to meet your diverse needs.

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