Fillet vs Chamfer: Considerations to Choose Between Fillets and Chamfers

Fillet vs Chamfer

The 3D models’ precise edges sometimes transition well to the physical world. Experts claim that rounded corners and edges are gentler on the eyes. They also simplify handling items and parts, potentially making them safer.

Unless the design softens or fractures such sharp edges, a newly machined metal product may have more tapered advantages than the end user wants. The design should use chamfers sloped, beveled edges and corners or fillets—rounded edges to provide an edge break.

Understanding the differences between fillet and chamfer is crucial, as most individuals confuse them. This is because the decision will determine whether the part manufacturing succeeds or fails.

Everything you need to learn about the fillet and chamfer, including their differences, will be covered in this article. Additionally, you will understand their key distinctions, when to employ them, and how to choose between them.

Fillet vs Chamfer 1

What is a Fillet?

In order to increase the aesthetics of your product design, using a fillet is the best option. Most commonly, a fillet is used to reduce stress and prevent deformations in your design – especially at the corners. Although they work best for exterior parts, using Fillets on sharp edges is also a safe option as it protects your workpiece from injury. Here are the three different types of fillets used in CNC machining:

Miter Fillet – Makes the manufacturing part more durable

Concave Fillet – Used on the interior sides

Convex Fillet – Used on the exterior sides


What is a Chamfer?

Compared to Fillets, a Chamfer is a straight, sharp, angeled edge commonly used for specific parts of your product design. It is usually beneficial in places where low-stress concentrations are required. Thus, it easily fits at an angle of 45 or 60. Here are the two main types of chamfers used in engineering techniques:

  • Rounded Chamfers

Table tops and counters widely use rounded chamfers to make the sharp edges smooth and round. The main focus of rounded chamfers is to protect from injury or to bruise by using special cutting tools such as chamfer planes.

  • Cornered Chamfers

The process in which sharp edges are flattened and made smooth either by hand or by using specialized cutting tools is called cornered chamfering. These chamfers give a good surface finish to your product and provide safe handling as well.


Fillet Vs Chamfer: Key Differences

sharp fillet chamfer edge

Sharp edges can be softened, or a gradual transition between two meeting surfaces can be made using fillets and chamfer. But you should be aware of the distinctions between Fillet and Chamfer. For a better understanding, we have compared both; read further about them.

1. Processing Method


Radius Machining

A specific size tool is needed to machine fillets with different radii (a larger fillet radius than the tool is good practice). Bevels don’t need a fixed tool size, and chamfers come in various sizes; all you need to do is manage the amount of cutting. What’s fascinating about fillet and chamfer is that in the CNC machining process, they both take an equal amount of time to process.

2. Machining Cost

The concave fillets’ bottom margins are difficult to create with CNC machinery because they require slower-cutting tools that will raise the cost of production. Hence chamfer offers a cheaper alternative by giving the option to remove the bottom edge’s rounded corners. If rounded edges are required, consider making them as broad as feasible.

3. Cutting Tools

You need specialized cutting equipment to manufacture fillets, mainly because of the difference in Radius. As a result, the cutting tools you need to employ depend on the type of Radius you wish to create. The single cutting tool can be used to develop several chamfer sizes; thus, your chamfer design does not require various tools and is more convenient.

4. Stress Concentration

The best thing about fillet is that it distributes the stress over a wider radius, preventing deformation of the part, and it works fabulously for the exterior. In contrast, a chamfer can put one portion under tremendous pressure, which makes the material prone to deformation.

5. Safety

Taking safety measurements is vital when using chamfer because of its sharp edges; on the other hand, fillets are easy to handle and make material driving safer.

6. Machining Time

When using the manual design method, chamfer offers less machining time than fillet, as the curved edges are difficult to engrave and take more patience. Therefore, fillet engineering consumes more time, whereas chamfering is faster.

7. Edges

Fillets have smooth edges used to craft round corners, but the chamfers hold sharp edges that can cause injuries if not handled properly.

8. Features

Typically, a fillet is an internal or external round feature at the corner of a part. Concave fillets are on the inside, and convex fillets are on the outside. However, the chamfer’s internal or external component edges are sloping or angled.

9. Functions

Rounded corners offer lower stress concentration and less flow resistance than chamfering. For this reason, using a fillet for shaping plastic items is preferable to chamfered corners unless the rounding extends to the two edges of the chamfered corner.

10. Aesthetics

For their aesthetically appealing qualities, rounded corners are frequently preferred in industrial design; thus, fillets win from an aesthetic standpoint. Bevels are rarely used in large areas of available products, but they can add a finishing touch and give some details a distinctive look.


What Factors to Consider When Choosing Between a Fillet and Chamfer?

Engineers and machining experts often need clarification when choosing between the two. Therefore, enlisted below are some crucial deciding factors that you should consider when choosing between a chamfer and a fillet:

a) Metal Parts

Industrial designers pay a lot of attention to the metal parts when choosing between fillet and chamfer. This is because the design of a product is significantly dependent on the use of the right tools and suitable metal workpieces. Following are some apparent differences in the metal parts of fillet and chamfer:

  • Manufacturing Time and Cost

In general, fillets require more manufacturing time and effort than chamfer. Moreover, the fillet edges and corners are not easy to manufacture – taking a lot of machining time. On the other hand, chamfers are pretty easy to make as they are straight-angled compared to fillets.

In terms of cost, fillets are more expensive than chamfers, so you should consider an enormous production cost when choosing fillets for your product.

  • Coating

When it comes to coating, rounded corners are better covered compared to beveled corners. The reason is that rounded corners can blend slowly with adjacent faces. Due to this, the adhesive ability of the part improves, leading to thicker and uniform coatings.

  • Stress

Fillets are the best choice if you wish to make large-radius exterior parts that can remain protected from deformations. They distribute the stress more widely on a large area and prevent high-stress concentration. Comparatively, chamfers have low-stress concentration and can significantly cause deformation in your design.

b) Plastic Part

Along with metal parts, chamfers and fillets show apparent differences in their plastic components, specifically in terms of molding and strength. Let’s have a look at them below:

  • Liquidity

When choosing between fillets and chamfer, the liquidity of raw materials should also be kept in mind. The rounded corners typically offer less flow resistance than chamfers. That’s why fillets are preferable to deal with plastic parts.

  • Strength

Undoubtedly, both fillets and chamfers serve the fundamental purpose of improving the load-bearing capacity of a machining part. Yet, fillets have more strength as compared to chamfers due to their greater load capacity and more comprehensive load range.

  • Mold Processing and Mold Strength

The firmness of the mold increases if the rounded corners are formed on the plastic components and parts of the mold are rounded too. It also facilitates mold processing and prevents excessive stress concentration during use. This makes the machining parts easy to handle during the casting and injection molding process. Moreover, a fillet can easily fit in cornered edges and rough surfaces.


Critical Points For Designing Fillet & Chamfer (In AutoCAD)

As you are aware, fillet helps transform sharp edges into round ones.

Though Circles and Trim can be used as its alternative command, its use will still be appreciated, given how simple arriving at the desired outcome is when employing it.

The Chamfer command is another excellent command in AutoCAD, and by utilizing this command, you can quickly generate a chamfer. We are mentioning critical points for designing fillet and chamfer in AutoCAD; read further to know about it.

Fillet Chamfer1

Chamfer Designing In AutoCAD

Using AutoCAD’s chamfer function, any two-dimensional object’s corners can be clipped at any given distance or angle. Choose the chamfer command in the Home tab’s Modify panel to utilize the chamfer command. Alternatively, enter “CHA” in the command bar and follow the following process.

Chamfer Command – (CHA)

  • Click on the Chamfer icon.
  • Enter the first chamfer ‘Distance’ or ‘ D ’ and press Enter.
  • Enter the second chamfer distance.
  • Then press Enter to process further.
  • Choose the first line.
  • Decide on line two.

Fillet Designing In AutoCAD

The time-saving Fillet command can join two lines, arcs, splines, or polylines at a sharp corner (0 angle radius) and any other angle or curve. Using the FILLET command in AutoCAD, you can generate an inner side corner, and an outside side corner referred to as fillets and around, respectively.

Fillet Command- (Fillet)

  • When utilizing the Fillet command, Type ‘F.’
  • Select the “Fillet” Command button.
  • Enter the fillet radius after typing R
  • Press Enter to Process further.
  • Choose the first line.
  • Decide on line two.


Fillet Vs Chamfer: Application in various Industries

The use of fillets and chamfers in CNC machining does not need any introduction. Besides their wide use in machining parts and industrial designs, here are some other industries that rely on the use of fillets and chamfers.

1. Aerodynamics

Aerodynamics includes aircraft components, including wings and struts. It runs on the four basic principles – the body, weight, load factors, and the effect of gravity. Using fillets in aerodynamics helps reduce interference drag and thus assists in the smooth movement of all components.

2. AutoCAD Industry

One of the significant use of fillets and chamfers is in the 2d and 3d modeling and drawing industry – simply known as AutoCAD. You can use the fillet command to join two lines or polylines or meet sharp edges. The best thing about the Fillet command is it connects the two parts by a tangent arc or perpendicular angle.

For instance, you can trim the end lines of an arc or make the corners sharp. Similarly, you can also create sharp corners by using cornered chamfers. This adds an aesthetic appeal to the object and makes the edges smooth.

3. Engineering Industry

Industrial engineers and designers make wide use of fillets and chamfers because they are crucial in the mechanical stress of a specific part. In CNC machining parts, chamfers are required to reduce the stress of sharp corners and thus make the edges round. Typically, a 45-degree chamfer proves best for the interior corners of the manufacturing part.

Moreover, fillets distribute and reduce the stress over an extensive area, making them practical, durable, and able to carry large loads. Engineers also use fillets to improve the fit of mated parts and the longevity of other machine components. These edge-breaking features come in different angles and shapes to fit your product design.



The article makes it easy to understand what a fillet and chamfer are. Both can be used for various things based on what you require. However, one of the most crucial choices when developing a part is picking the one that works best for your design. This is so that a plan can be made that is more effective, saves money, and lasts longer. While comparing chamfer, fillet, and bevel can result in higher-quality, more cost-effective designs.

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