The Essential Toolkit: Most Used Bits for CNC Machine

Welcome to the dynamic world of CNC machining, where precision tools meet creative vision. In our latest blog, we delve deep into the most used bits for CNC machines, uncovering the secrets behind their selection and application. From the versatile flat end mills to the precision-driven ball nose end mills, we explore a variety of bits that cater to different materials and projects. Discover how specialty bits like roughing end mills and thread mills can transform your advanced applications, and learn the art of choosing the right bit to match both the material at hand and your machine's capabilities. But it's not all about selection; we also emphasize the critical importance of maintenance and care for these essential tools. Join us on this informative journey and elevate your CNC machining projects to new heights of precision and efficiency.

Welcome to the intricate and fascinating world of CNC machining, a domain where precision engineering meets artistic creativity. At the heart of any CNC masterpiece lies an often understated yet pivotal component: the CNC bits. These small but mighty tools are crucial in defining the quality, efficiency, and precision of your CNC projects.

Have you ever found yourself overwhelmed by the vast array of CNC bits available in the market? Or perhaps, you’ve wondered which bits are absolutely essential for your CNC toolkit? Worry not! This comprehensive guide is crafted to demystify the world of CNC bits for everyone, from seasoned machinists to hobbyists just starting their journey.

In this blog, we’ll embark on an explorative journey through the most commonly used CNC bits. We’ll delve into their diverse applications, uncover their unique advantages, and provide insights on selecting the perfect bit for any project. Our goal is to equip you with the knowledge and confidence to make informed choices about the tools you use, ensuring every CNC project you undertake is a step towards mastery.

So, buckle up and prepare to dive deep into the heart of CNC machining. Whether you’re looking to refine your skillset or simply satisfy your curiosity, this guide promises to be your compass in the vast sea of CNC bits!

Part 1: Understanding CNC Bits

The Role of CNC Bits in Machining

CNC (Computer Numerical Control) bits, often referred to as router bits or end mills, are the cutting tools used in CNC machines. They are the sculptors of materials, shaping everything from metals to wood to plastics, with precision and accuracy. Each bit type is designed for specific materials and applications, making their understanding crucial for anyone involved in CNC machining.

Materials Used in CNC Bits

  • Carbide: This is a popular choice for CNC bits due to its high strength and resistance to wear. Carbide bits maintain a sharp edge longer than most other materials, making them ideal for cutting harder materials.
  • High-Speed Steel (HSS): HSS bits are more economical than carbide and work well for softer materials like wood or plastic. However, they dull faster and aren’t suited for prolonged use on metals.
  • Cobalt: Cobalt bits are an upgrade from HSS and are used for tougher materials like stainless steel. They withstand higher temperatures, maintaining their hardness in demanding environments.
  • Diamond-Coated: These bits are used for very hard materials. The diamond coating provides an extra level of hardness and durability, ideal for abrasive materials.

Anatomy of a CNC Bit


Understanding the parts of a CNC bit is crucial for selecting the right bit for a job:

  • Cutting Edge: This is the part of the bit that does the actual cutting. The design of the cutting edge varies based on the material and type of cut required.
  • Flutes: Flutes are the grooves in the bit that allow chips to escape, reduce friction, and keep the bit cool. The number of flutes can range from one to four or more, depending on the application.
  • Shank: The shank is the part of the bit that is held by the CNC machine’s collet. It’s crucial that the shank is made of a material that can withstand the forces of the machine without bending or breaking.
  • Tip: The tip of the bit determines the shape of the cut. For example, a pointed tip is used for detailed engraving, while a flat tip is used for making straight cuts.

Types of CNC Bits

  • Flat End Mill: Ideal for making flat-bottomed cuts and sharp-edged contours.
  • Ball Nose End Mill: Excellent for 3D contouring and creating smooth, rounded grooves.
  • V-Bit: Used primarily in carving, especially for fine details and engraving.
  • Compression Bit: Combines the properties of upcut and downcut bits, ideal for cutting laminated materials without chipping.

Choosing the Right Bit

The choice of bit greatly affects the quality of the finished piece. Factors like the material being cut, the type of machine being used, and the desired finish all play a role in bit selection. Understanding the strengths and limitations of each bit type is key to successful CNC machining.


In the realm of CNC machining, the bit is more than just a tool; it’s the bridge between your creative vision and the finished product. By understanding the various types of CNC bits, their materials, and applications, you can make informed decisions that lead to better quality, efficiency, and artistic expression in your work.

Part 2: Most Common Types of CNC Bits

55° Aluminum Carbide Three-Flute Rough Milling Cutter


CNC bits come in various shapes and sizes, each designed for specific applications. Understanding the most common types of CNC bits and their uses is essential for anyone involved in CNC machining. This section will explore the most frequently used CNC bits, their distinctive features, and typical applications.

Flat End Mills

  • Description: Flat end mills, also known as square end mills, have a flat bottom with straight edges. They are among the most versatile CNC bits, used for a wide range of applications.
  • Applications: Ideal for creating flat surfaces and sharp, straight edges. They are commonly used in slotting, profiling, and even in some drilling operations.
  • Materials: Suitable for a variety of materials, from softwoods and plastics to harder metals like steel.
  • Variations: Available in various sizes and flute configurations, from 2-flute designs for softer materials to 4 or more flutes for harder materials.

Ball Nose End Mills

  • Description: These bits have a rounded tip, resembling a ball. They are used to create smooth, contoured surfaces.
  • Applications: Perfect for 3D contouring, sculpting, and where a smooth finish is required. Often used in mold making, die sinking, and creating complex 3D shapes.
  • Materials: Effective on a range of materials, including wood, plastics, and metals.
  • Variations: Different sizes and flute counts are available, with smaller diameter bits used for finer detailing.
HRC55° tungsten steel 4-blade round nose milling cutter


  • Description: V-bits have a conical shape with a varying angle. These are primarily used for engraving and detailed carving.
  • Applications: Widely used in sign-making, fine woodworking, and detailed engraving work. The angle of the bit determines the width and depth of the engraving.
  • Materials: Effective on wood, plastic, and softer metals like aluminum.
  • Variations: Available in different angles, typically ranging from 30 to 90 degrees, for various levels of detail.

Compression Cutters

  • Description: Compression cutters combine the properties of upcut and downcut bits. They have flutes that go in opposite directions.
  • Applications: Ideal for cutting laminated materials or any application where preventing splintering on both sides of the cut is crucial.
  • Materials: Commonly used on wood, plywood, laminates, and sometimes plastics.
  • Variations: Come in various sizes, with the length of the upcut and downcut flutes varying based on the material thickness.

Additional Common Bits

  • Upcut and Downcut Spiral Bits: These bits are designed to either pull chips up or push them down. Upcut spirals are great for efficient chip removal, while downcut spirals produce a cleaner top surface.
  • Fishtail Bits: Ideal for fine, detailed work and creating clean, sharp corners.
  • Tapered Bits: Used for deep, intricate carving, often in relief artwork or detailed 3D modeling.


The choice of the right bit can significantly influence the quality and efficiency of your CNC machining projects. From flat end mills for basic cutting to specialized V-bits for intricate engraving, understanding the characteristics and applications of these common CNC bits is crucial for any machinist. By selecting the appropriate bit for your material and project, you can ensure precision and excellence in your CNC creations.

Part 3: Specialty Bits for Advanced Applications


While basic CNC bits handle most tasks, specialty bits are designed for specific, often more challenging applications. These bits can significantly enhance precision, efficiency, and quality in advanced machining projects.

Roughing End Mills

  • Description: Roughing end mills, also known as hoggers, are designed for quickly removing large amounts of material.
  • Applications: Ideal for the initial roughing phase in machining, where speed is more critical than finish quality. They reduce the load and heat on the bit, which increases its lifespan.
  • Materials: Used on a wide range of materials, including metals, wood, and plastics.
  • Unique Features: Characterized by a wavy tooth form to break up chips, reducing vibration and enabling faster feed rates.
55° 3-Flute Rough Skin Aluminum Wave Edge End Mill

Thread Mills

  • Description: Thread mills are used to create threads in a workpiece. Unlike taps, they can produce different thread sizes with the same tool.
  • Applications: Perfect for threading holes of various sizes and producing threads close to the bottom of blind holes.
  • Materials: Commonly used on metals and hard plastics.
  • Advantages: Provide greater flexibility than taps and dies, with less risk of breaking.

Tapered End Mills

  • Description: Tapered end mills have a conical cutting head that is wider at the shank and narrows down to the tip.
  • Applications: Used in mold making, die casting, and in the aerospace industry. They are essential for machining angles, creating draft angles in mold and die making, and for sculpting complex 3D shapes.
  • Materials: Effective on a variety of materials, including metal, wood, and plastic.
  • Benefits: The tapered design offers increased strength and rigidity, allowing for precise milling in deeper areas without bending.

Dovetail Cutters

  • Description: Dovetail cutters have an angular, fluted cutting head designed to create dovetail slots.
  • Applications: Primarily used in joinery for woodworking, especially in making dovetail joints for drawers and boxes.
  • Materials: Typically used on wood and occasionally soft metals.
  • Variations: Available in different angles and sizes to match the requirements of the dovetail design.

Drill Mills

  • Description: Drill mills have a pointed tip and can be used for both drilling and milling applications.
  • Applications: Versatile tools used for spot drilling, chamfering, and profile milling. They are particularly useful in situations where tool change needs to be minimized.
  • Materials: Suitable for a range of materials, including metals, woods, and plastics.
  • Advantages: Their versatility makes them a valuable addition to a CNC toolkit, especially for workshops with limited tool inventory.
55° 2-flute carbide positioning drill


Specialty CNC bits are indispensable for advanced and specific applications where standard bits might not suffice. Whether it’s roughing large materials efficiently with roughing end mills, creating precise threads with thread mills, or sculpting complex geometries with tapered end mills, these specialty bits open up new possibilities in CNC machining. Understanding and utilizing these tools can significantly enhance the capabilities of any CNC machinist or workshop, pushing the boundaries of what can be achieved with CNC technology.

Part 4: Selecting the Right Bit for Your Project


Selecting the right CNC bit is as critical as the design or the material you choose for your project. The appropriate bit can make the difference between a mediocre piece and a masterpiece. This section aims to provide a comprehensive guide to choosing the most suitable CNC bit for different projects.

Understanding the Material

  • Material Properties: The first step in bit selection is understanding the material’s properties. Hard materials like metals require bits with fewer flutes and made of tougher materials like carbide, while softer materials like wood can be cut with bits having more flutes.
  • Material Behavior: Consider how the material behaves during machining. For example, some woods may chip or splinter, requiring specific types of bits like compression cutters.

Matching Bit to Machine Capabilities

  • Spindle Speed: The capability of your CNC machine, particularly the spindle speed, plays a significant role in bit selection. High-speed spindles can handle bits with more flutes, which produce a finer finish.
  • Torque and Power: The power and torque of your machine determine the size and type of bit it can handle effectively. Larger bits require more power and torque to operate efficiently.
55° 2-flute 90° front angle steel centering drill

Considering the Project Requirements

  • Type of Cut: The nature of the cut – whether it’s a detailed engraving or a basic cut – dictates the bit selection. Fine, detailed work requires bits with sharper angles and finer tips, like V-bits or fishtail bits.
  • Finish Quality: The desired finish quality also influences bit choice. For a smoother finish, use bits with more flutes. For rougher, quicker cuts, bits with fewer flutes are preferable.
  • Complexity of Design: Complex designs with intricate details or deep cuts may require specialized bits like tapered bits or detailed carving bits.

Technical Considerations

  • Feed Rate and Speed: Understanding the relationship between feed rate, cutting speed, and bit type is crucial. Different bits perform optimally at different speeds and feed rates.
  • Coolant Needs: Some bits, especially those used for metals, may require coolant to prevent overheating.

Practical Tips

  • Start with a Small Selection: Beginners should start with a basic selection of bits and gradually expand their collection as they gain experience and understand their specific needs.
  • Experiment and Learn: Experimentation is key in CNC machining. Try different bits on scraps of your material to understand how they behave.
  • Consult Experts and Communities: Join online forums, watch tutorials, and consult with experienced machinists to get advice on bit selection for specific projects.


Selecting the right CNC bit for your project is a blend of understanding your material, machine capabilities, project requirements, and technical considerations. It’s not just about the bit itself, but how it interacts with all these factors to produce the desired outcome. With the right knowledge and a bit of experimentation, you can choose the best bit for any project, ensuring quality and efficiency in your CNC machining endeavors.

55° 2-flute tungsten steel CNC ball end milling cutter

Part 5: Maintenance and Care for CNC Bits


Proper maintenance and care of CNC bits are as crucial as selecting the right bit for a project. Well-maintained bits ensure consistent performance, precision in cuts, and longevity of the tools. This section delves into best practices for maintaining and caring for your CNC bits.

Regular Cleaning

  • Importance of Cleaning: Accumulated debris and residues can affect the cutting efficiency and lifespan of CNC bits. Regular cleaning prevents build-up and ensures optimal performance.
  • Cleaning Methods: Use appropriate cleaning solutions and brushes to remove debris. For resinous materials, solvents or specialized bit cleaning solutions may be required. Ensure the bits are completely dry before storing.

Proper Storage

  • Organized Storage: Store bits in a dry, organized manner. Individual slots or holders are preferable to prevent bits from knocking against each other, which can dull the edges.
  • Environment Considerations: Avoid areas with high humidity or temperature fluctuations to prevent rust and degradation of the bits.

Sharpening and Reconditioning

  • Recognizing Dullness: Learn to recognize signs of dullness, such as burning on the material, rough cuts, or increased resistance during cutting.
  • Sharpening Techniques: Use appropriate sharpening tools or services. Some bits, especially carbide, may require professional re-sharpening due to their hardness.
  • Frequency of Sharpening: Sharpen bits as soon as they show signs of dullness. Regular, light sharpening is better than waiting until the bit is significantly dulled.

Inspecting for Wear and Damage

  • Regular Inspection: Regularly inspect bits for signs of wear, damage, or bending. Even minor damage can significantly affect the quality of your cuts.
  • Handling Damaged Bits: If a bit is damaged, assess whether it can be repaired or if it needs to be replaced. Using damaged bits can be dangerous and result in poor quality work.

Upkeep of Coatings

  • Understanding Coatings: Many high-performance bits come with coatings for increased durability and efficiency. These coatings can wear over time and affect performance.
  • Maintaining Coatings: Avoid aggressive cleaning methods that can strip away coatings. If the coating wears off, consider re-coating or replacing the bit.

Replacement Strategy

  • When to Replace: Understand when a bit is beyond repair. Continuously using a worn or damaged bit can lead to poor work quality and can be a safety hazard.
  • Inventory Management: Keep a record of bit usage and replacements. This helps in understanding the lifecycle of different bits and planning for replacements.


As we conclude our deep dive into the world of CNC bits, it’s clear that these tools are more than mere accessories; they are the keystones of precision and creativity in CNC machining. From understanding the basics of CNC bits, exploring the most common types, delving into specialty bits for advanced applications, selecting the right bit for specific projects, to maintaining and caring for these crucial tools, each step is pivotal in the journey towards mastery in CNC machining.

Remember, the right bit not only enhances the quality and efficiency of your work but also breathes life into your creative visions. The knowledge you’ve gained about CNC bits will not only guide your selections but also expand your horizons in what you can achieve with your CNC machine. Combine this knowledge with regular maintenance and care, and you have a recipe for success in any CNC project.

We encourage you to revisit this guide whenever you’re in doubt, and always keep exploring and experimenting with different bits and techniques. The world of CNC machining is vast and ever-evolving, and your journey in it is only limited by your imagination. Happy machining!

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