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Tom Beaumont

Product Training Manager

18 years engineering experience, specialising in 3 & 4 axis CNC milling, turning and horizontal boring.

Milling cutters come in different geometries and flute counts, it is important to choose the right one based on the machining conditions, such as different materials and the desired outcome.


In this blog we discuss the different types of flutes and what each geometry is best used for.


What are flutes on a milling cutter?

Milling cutter flutes are the grooves or channels found on the cutting edge of a milling tool. These flutes play a crucial role in chip removal, feed rates and surface finish during the milling process. They aid in the efficient evacuation of chips or swarf.

What number milling cutter flutes are available and why you would choose them?

1 Flute Milling Cutters:

1 flute milling cutters, also known as single flute cutters, are specifically designed for milling applications involving soft materials like aluminium. These cutters are preferred for their ability to effectively handle long swarf without clogging up the flutes. The larger chip pockets provided by the single flute design facilitate efficient chip evacuation, preventing chip buildup and ensuring uninterrupted machining. Single flute milling cutters can be used for different applications, including slotting and finishing. The 1 Flute Milling Cutter from Atorn is an ideal choice which allows for excellent work piece finishes and chip evacuation.

2 Flute Milling Cutters:

With their versatility, 2-flute milling cutters are suitable for general-purpose milling operations. These cutters excel in chip evacuation and work well with materials such as steel, stainless steel, aluminium, and plastics. They are commonly used for slotting and plunge milling.

3 Flute Milling Cutters:

3-flute milling cutters strike a balance between chip evacuation and tool rigidity. They provide smoother cutting and improved surface finish compared to 2-flute cutters. Materials like aluminium, brass, and composites are suitable for these cutters, and they find applications in pocketing, slotting, and roughing operations.

4 Flute Milling Cutters:

For enhanced tool stability and higher feed rates, 4-flute milling cutters are a preferred choice. They are compatible with materials like steel, stainless steel, cast iron, and non-ferrous metals. Side milling, face milling, and finishing operations commonly utilise 4-flute cutters. The 4G Mill range from YG-1 offers an unbeatable performance and accuracy in high speed machining of all carbon or alloy steels, pre-hardened steels (up to HRc55), stainless steel and cast iron. The micrograin carbide substrate and Y1200 coating offers extreme cutting life in temperatures up to 1,200°C

5 Flute Milling Cutters:

5-flute milling cutters are designed to provide improved surface finish while minimising vibration. They work effectively with materials like steel, stainless steel and HRSA’s. Finishing, profiling, trochoidal and high-speed machining benefit from the capabilities of 5-flute cutters.

6 Flute Milling Cutters:

For improved surface finish and higher feeds rates, 6-flute milling cutters are a reliable option. They are suitable for materials such as steel, stainless steel and HRSA’s. Finishing, profiling, trochoidal and high-speed machining operations often leverage the benefits of 6-flute cutters. The V7 Plus 6 Flute Milling Cutter provides the fastest metal removal rates, even in deep slots or profiling up to 2xD.

What other milling cutter flute geometries are available?

Multiple Helix:

Milling cutters with multiple helix flute design offer improved swarf evacuation by breaking up and removing chips efficiently. Each flute engages with the material, contributing to better chip removal, reduced heat generation, and improved surface finish. The V7 Plus 4 Flute Milling Cutter is the first choice for cutting a wide range of materials with high removal rates and exceptional tool life.

Variable Helix:

Milling cutters with variable helix flutes feature varying geometries along the cutting edge, reducing sound and vibration during machining. By distributing cutting forces evenly, these cutters enhance tool stability, surface finish, and tool life. They are particularly advantageous in high-speed machining and when working with materials prone to vibration or chatter.


Rippers are specialised milling cutters designed for roughing applications, enabling rapid material removal. Equipped with coarse or fine pitch teeth, rippers are effective in tackling challenging materials and demanding roughing operations. The X-Speed Rougher End Mills are ideal in steel and cast iron applications, this system provides silent machining with 2-3 times faster removal rates.

Straight Flutes:

Straight flutes, featuring parallel grooves along the cutting edge, are ideal for cutting soft materials like aluminium and plastics. While they have a simple design, it's important to note that straight flutes may not offer optimal chip evacuation and can occasionally lead to chip clogging depending on the material type.


Choosing the right flute geometry is crucial for optimising milling operations. By considering factors such as material properties, cutting conditions, and desired outcomes, you can select the most suitable milling cutter flute for your specific application. Understanding the benefits of different flute types empowers you to achieve superior chip evacuation, improved surface finish, and enhanced tool stability during the machining process.

For expert advice on choosing the correct milling cutter flute and geometry type please contact our technical team on 01924 869 615 or email

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