• June 21, 2024
  • Shatou, Changan, Dongguan, CN
fillet and chamfer

The difference between fillet and chamfer

“Filleting” and “chamfering” refer to the treatment of the edges of objects to make them smoother. These two methods are often applied in design and manufacturing due to their ability to enhance the appearance and functionality of objects. However, there are some significant differences between fillets and chamfers, which will be described in detail below.

Fillets and Chamfers
Fillets and Chamfers

Definition of fillets and chamfers

Chamfering and filleting are two different methods for processing the edges of an object.

A chamfer is an inner or outer corner with a bevel, which is often used in machining, furniture making, woodworking, and other fields. A 45° chamfer can remove burrs and bury the screw heads into the surface, while a 60° chamfer is often used for screw leads. Chamfers help prevent edge damage and improve edge consistency, making them an essential tool in many industries.

Fillets play an important role in mechanical engineering as they reduce stress concentrations and increase the strength and load-carrying capacity of parts. Additionally, rounded corners remove sharp edges and decrease the risk of injury and damage. Machinists frequently use fillets on welds and connections to ensure a good joint. To achieve an optimized design effect, machinists use lines with concave and convex functions, creating rounded geometry on both inner and outer corners.

Difference Between Fillet and Chamfer

PurposeThe chamfer of the orifice plays the role of introduction, and the outer surface is mostly chamferedAvoid sharp edges hurting people, use rounded corners on the inner surface
FeatureThe chamfer is a sloped or angled corner in the internal or external part edge.Fillet is an internal or external round feature at the corner of a part. Exterior fillets are convex, and internal fillets are concave.
Tools1 tool can machine different size of chamferNeed different tools to machine different size fillet
TimingShort machining timingLong machining timing
SafetyThe sharp edges may lead to injuryIt offers better safety for handling materials
AttractivenessSimple designAesthetically pleasing
Stress ConcentrationEngineers add a chamfer in a corner where high-stress concentration is required because it focuses the mechanical stress in a specific section.Engineers use fillets to distribute the stress over a large area and avoid a high-stress concentration area.
CoatingThere are still sharp edges at the chamfer, and the coating is easy to peel offIf coating is required, rounded corners are the best choice

When do you need fillets and chamfers?

Situations that require fillets and chamfers include the following:

1. Part design

When designing parts, rounded corners or chamfers are often added to the edges to reduce stress concentration, protect the sharp edges of bolts or screws from wearing out, and make assembly easier.

2. CNC milling

During the process of CNC milling, it is a common practice to round or chamfer the edges and corners of the workpiece. This is done to enhance the surface quality of the final product and to decrease the number of milling edges required by the tool.

3. Processing of machine tools and parts

During the processing of machine tools, parts with sharp edges and corners can cause difficulties. To reduce friction and processing difficulties, it is recommended to process rounded corners or chamfers.

4. Cost and wear

Sharp edges can cause increased wear on bolts and screws during use, ultimately leading to higher replacement and maintenance costs. As a result, rounded corners are often processed in situations that require long-term use and high durability. Alternatively, chamfered edges can be utilized to reduce the degree of wear.

The manufacturing process for fillets and chamfers

1. Design

First, determine the parts and dimensions that need to be rounded or chamfered in accordance with the product design requirements.

2. Cutting

Rounded corners and chamfers are usually achieved by cutting. To meet the design requirements, you must select the appropriate cutting process and cutting tools, such as a milling cutter, chamfering cutter, etc. The workpiece should be clamped on the processing equipment for cutting purposes. The specific cutting method can be milling, turning, drilling, or others.

3. Use special machine tools

A special rounding machine or chamfering machine can be used to achieve rounding, and the workpiece can be positioned and processed by adjusting the tools and fixtures on the machine tool. This method can improve processing efficiency and precision.

4. Manual grinding

For some small or complex workpieces, manual grinding can be used to round and chamfer them. This is achieved by manually grinding the workpiece using tools such as grinding wheels.

5. Surface treatment

After rounding and chamfering are completed, the workpiece can be surface-treated, such as by grinding, polishing, etc., to improve appearance quality and smoothness.

It is important to note that, when processing rounded corners and chamfers, the appropriate cutting process and tools should be selected based on the material, size, and requirements of the workpiece to ensure processing quality and efficiency. Moreover, operators should pay attention to safety and use personal protective equipment to avoid accidental injuries.

How to save the cost of fillets and chamfers?

There are several ways to save on the cost of fillets and chamfers:

1. Select the appropriate machining method

Traditionally, fillet and chamfer machining methods require the use of grinding machines or machine tools for machining, which can increase costs. However, fillets and chamfers can be achieved more efficiently with advanced machining methods such as laser cutting or EDM.

2. Design reasonably rounded corners and chamfering radii

Designers can choose appropriate rounded corners and chamfering radii when designing products to minimize material waste and processing difficulty. Typically, smaller radii require more machining steps and more complex operations, resulting in increased costs.

3. Use standardized filleting and chamfering tools

Choose to use standardized filleting and chamfering tools already available on the market, which can help reduce costs. These tools typically have standardized radii and shapes, thus reducing the time and cost required for custom machining.

4. Optimize the design to reduce the number of fillets and chamfers

Please carefully review the design and minimize the number of fillets and chamfers used. Use fillets and chamfers only where necessary and use squares elsewhere. Doing so will save on material and tooling costs.

5. Consider using other materials

Certain materials may be better suited to achieve fillets and chamfers without additional processing steps and costs. For example, aluminum alloys are generally easier to machine and fillet without requiring additional steps of machining.


Generally, both chamfering and rounding can smooth out edges, reduce damage, and improve the appearance and comfort of products. The difference is that chamfering turns right angles into bevels or angles, while rounding turns right angles into arcs. The choice of which edge treatment method to use should be determined according to the characteristics and needs of the material being processed.

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