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A Beginners Guide to Milling Bits and Their Uses in CNC Machining

By May 17, 2024May 20th, 2024Blog

A Beginners Guide to Milling Bits and Their Uses in CNC Machining

CNC milling is a versatile manufacturing process that involves the use of various types of milling bits to achieve precise cuts and intricate designs on a wide range of materials. Understanding the different types of milling bits and their specific uses can greatly enhance the efficiency and quality of your machining projects. In this guide, we will explore the various milling bit types, their uses, and the materials they are made from.

Materials Used in Milling Bits

  1. High Speed Steel (HSS)

Description: High Speed Steel (HSS) is an alloy steel that is highly versatile and affordable. HSS bits are widely used for general-purpose machining due to their balance of toughness, hardness, and wear resistance. They can handle a variety of materials, including steel, aluminum, and plastic, making them suitable for a wide range of applications in both industrial and hobbyist settings.


  • Versatility in cutting different materials
  • Cost-effective
  • Easy to re-sharpen and maintain
  1. Carbide

Description: Carbide bits are composed of tungsten carbide, which is a very hard and wear-resistant material. These bits are significantly harder than HSS and are designed for high-speed applications. Carbide bits excel in machining tough materials like stainless steel and titanium, and they maintain their cutting edge for a longer duration, reducing the need for frequent tool changes.


  • High hardness and wear resistance
  • Excellent performance at high speeds
  • Long tool life
  1. Cobalt Steel

Description: Cobalt steel bits are a variation of high-speed steel with a higher cobalt content, typically around 5-8%. This addition enhances the bit’s heat resistance and durability, making them suitable for machining hard and abrasive materials. Cobalt steel bits are particularly effective in cutting materials like stainless steel and superalloys, where standard HSS bits might fail.


  • Superior heat resistance
  • Increased durability and toughness
  • Ideal for hard and abrasive materials
  1. Diamond Coated

Description: Diamond-coated bits are infused with a layer of diamond particles, providing extreme hardness and wear resistance. These bits are ideal for machining highly abrasive materials like graphite, composites, and ceramics. Diamond-coated bits offer exceptional performance in applications that require precision and smooth finishes, especially in industries such as aerospace and electronics.


  • Exceptional hardness and wear resistance
  • Excellent for abrasive materials
  • Produces smooth and precise finishes
  1. Tool Steel

Description: Tool steel bits are made from a variety of steel alloys known for their hardness, toughness, and ability to hold a cutting edge. These bits are designed for heavy-duty machining applications and can cut through hard materials with ease. Tool steel is commonly used in manufacturing industries where robust and reliable cutting tools are essential.


  • High toughness and durability
  • Suitable for heavy-duty applications
  • Maintains sharp cutting edges under tough conditions

Each of these materials offers distinct advantages depending on the specific requirements of the machining operation, making the selection of the appropriate material crucial for achieving optimal results.

Types of Milling Bits

Ball End Mills

Uses: Ball end mills are used for contour milling, surface finishing, and 3D milling applications. They are perfect for creating smooth, rounded edges. These mills are ideal for sculpting intricate designs and detailed shapes.

Chamfer Cutters

Uses: Chamfer cutters are used for creating beveled edges and deburring parts. They are essential for edge preparation before welding. These cutters help to improve the finish and functionality of machined parts.

Corner Radius End Mill

Uses: These end mills have a rounded corner, which reduces the risk of chipping and extends tool life. They are used for filleting and edge blending. Corner radius end mills are great for reducing tool wear and creating more durable parts.

Dovetail Cutters

Uses: Dovetail cutters are used for creating dovetail joints and undercuts. They are essential in woodworking and precision metalworking. These cutters provide secure, interlocking joints that are strong and durable.

Drill Mills

Uses: Drill mills combine the capabilities of drilling and milling into one tool. They are used for drilling, chamfering, and milling operations. This versatility makes them suitable for complex machining tasks.

Face Mills

Uses: Face mills are used for facing operations to create a flat surface on the workpiece. They have multiple cutting edges for efficient material removal. Face mills provide a high-quality surface finish and are efficient for large-area cuts.

Flat End Mill

Uses: Flat end mills are used for cutting flat surfaces, grooves, and pockets. They are ideal for plunge cutting, slotting, and contouring. These mills are versatile and commonly used for general-purpose machining.

Fly Cutters

Uses: Fly cutters are single-point cutters used for machining large, flat surfaces. They are often used for facing operations. Fly cutters are economical and capable of producing excellent surface finishes.

Form Cutters

Uses: Form cutters are used for machining complex shapes and profiles. They are custom-made for specific applications. These cutters are essential for creating unique and precise forms.

Gear Cutters

Uses: Gear cutters are used for machining gears and gear teeth. They are available in various shapes and sizes for different gear profiles. These cutters are crucial for producing accurate and efficient gear systems.

Hollow Mills

Uses: Hollow mills are used for machining cylindrical shapes and producing internal profiles. They are commonly used in pipe and tube manufacturing. These mills are ideal for creating consistent and uniform internal dimensions.

Roughing End Mills

Uses: Designed for high material removal rates, roughing end mills have serrated cutting edges that break up chips and reduce cutting forces. They are excellent for rapid stock removal and roughing out shapes.

Router Bits

Uses: Router bits are used for cutting and shaping wood, plastic, and composite materials. They come in various shapes for different applications. These bits are versatile and essential for detailed woodworking and plastic shaping tasks.

Shell Mills

Uses: Shell mills are used for high-efficiency milling operations. They have replaceable cutting edges and are used for roughing and finishing. Shell mills are perfect for heavy-duty and high-volume production.

Slab Mills

Uses: Slab mills are used for heavy cutting and large surface area machining. They are ideal for cutting wide, flat surfaces. These mills are suitable for large-scale material removal and creating broad, flat surfaces.

Square End Mills

Uses: Similar to flat end mills, square end mills are used for general milling applications. They can create sharp corners in the workpiece. These mills are essential for precision work and detailed cuts.

T-Slot Cutters

Uses: T-slot cutters are used for machining T-slots in worktables and fixtures. They allow for the creation of slots that hold T-bolts. These cutters are vital for creating secure and adjustable work holding setups.

Thread Mills

Uses: Thread mills are used for creating internal and external threads. They offer flexibility and can produce threads of various sizes. These mills are ideal for producing high-quality threads with precise tolerances.

Woodruff/Key Seat Cutters

Uses: Woodruff cutters are used for cutting keyways and producing Woodruff keys. They are widely used in the automotive and aerospace industries. These cutters ensure secure and reliable keyways for various mechanical applications.


Selecting the right milling bit for your CNC machining project is crucial for achieving optimal results. By understanding the various types of milling bits and their specific uses, you can ensure efficient and precise machining operations. Whether you are working with metals, plastics, or composites, there is a milling bit designed to meet your needs. Always consider the material of the bit and the workpiece to achieve the best performance and tool life.

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