When it comes to CNC machining, your results are only as good as the tools you use. At Techno CNC Shop, precision-engineered router bits are crafted to deliver clean, efficient, and professional-grade cuts across a wide range of materials. In this guide, we’ll explore some of the top CNC router bits available and help you determine which are best suited for your projects.
🔧 Why Router Bit Selection Matters
Choosing the right router bit is crucial for:
Cut quality – Preventing tear-out, rough edges, or melting.
Tool longevity – Using the correct geometry and flute type for each material reduces wear.
Efficiency – Faster, cleaner cuts mean more productivity with less rework.
Material compatibility – Different materials (wood, plastic, aluminum) demand different flute styles and coatings.
⚙️ Tips for Choosing the Right Bit
Flute Direction:
Down-cut: Best for clean top edges
Up-cut: Best for clean bottom edges and faster chip removal
Compression: Best for double-sided clean cuts
Material Matching:
Always match bit geometry and coating with the material you’re working with to prevent damage and extend tool life.Shank Size & Router Compatibility:
Make sure your router supports the bit’s shank diameter for safe and stable operation.
Most popular Router Bits
1. SW141434-2D Solid Carbide Down-Cut Bit
Best for: Wood and plywood
Key Benefit: Down-cut flutes push chips downward, producing a clean top surface without fraying.
Use Case: Ideal for cabinetry, furniture components, and laminated panels.
2. CM141478 Compression Bit
Best for: Laminated plywood and MDF
Key Benefit: Combines up- and down-cut flutes, compressing material fibers for clean edges on both sides.
Use Case: Essential for double-sided finish work where both edges must be clean.
3. PL3838118-1U O’Flute Up-Cut Bit for Plastics
Best for: Acrylic, PVC, and other soft plastics
Key Benefit: Polished flutes help with chip evacuation, reducing heat and preventing melting.
Use Case: Acrylic signs, plastic enclosures, anything ‘plastic’ and decorative panels.
What’s the difference between an Up-cutter and a down-cutter?
The difference between an upcut and a downcut CNC router bit comes down to the direction the bit moves the material chips and how it affects the edge finish of the cut:
Upcut Bit:
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Chip Direction: Pulls chips upward, away from the cutting surface.
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Top Edge Finish: Rougher.
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Bottom Edge Finish: Cleaner.
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Use Case: Great for deeper cuts and when chip removal is a priority (helps prevent overheating and bit wear).
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Best For: Plastics, aluminum, and wood when bottom-edge finish is more important.
Downcut Bit:
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Chip Direction: Pushes chips downward, into the material.
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Top Edge Finish: Cleaner.
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Bottom Edge Finish: Rougher or prone to chip-out.
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Use Case: Ideal for shallow cuts or surface details where top-surface finish matters.
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Best For: Plywood, laminates, and when you’re trying to avoid top surface tear-out.
Summary:
Upcut = Better chip ejection + clean bottom
Downcut = Cleaner top finish + less edge splintering
Some users also choose compression bits, which combine both styles—upcut at the tip and downcut at the top—for clean edges on both sides.
Feeds and speeds
Select the Right Cutting Tools and Calculate Proper Feeds and Speeds
The key to optimizing your Techno CNC equipment and getting the best cut quality at the most efficient rate all depends on the tool selection and proper feeds and speeds calculation. Since these seemingly small variables have such a large impact on the outcome of a CNC project, it is crucial that operators and programmers understand the methods in which a bit is selected and how to calculate the proper feeds and speeds for the cutting tool. CNC router bit choice is important in regard to chip load, which is the size of the chip produced for every cutting edge (flute) on the tool per revolution of the spindle. The goal with chip load is to maximize the size of the chips increasing productivity, reducing heat produced on the tool, and preventing premature dulling. A chip load that is too small will produce a lot of heat, causing the bit to dull very quickly, inevitably breaking the cutting tool. A chip load that is too large will cause the tool to deflect, producing a “chatter” cut finish and in some extreme cases, break the tool.
Selecting a router bit
Materials: Router bits are produced in a variety of material The most common are solid carbide, carbide-tipped steel, and high-speed steel. The Techno CNC tools are all produced using solid carbide as this material is proven to be a much stronger make up and will stay sharper longer. We do not recommend using high-speed steel bits, as they are prone to dulling quickly and needing to be re-sharpened.
Flute Shapes: Router bits are formed into three different, yet distinct shapes; straight, spiral up-cut, spiral down-cut, and compression. Each style has advantages and disadvantages which we have listed in the chart below.
Number of Flutes: The number of flutes on a cutting tool is an essential variable to calculating proper feeds and speeds to run on your CNC machine. For most applications a tool utilizing 1, 2, or 3 flutes can be used, adjusting feeds and speeds in order to maintain the proper chip load.
Bottom Geometry: Cutters with a spiral up cut and straight flute shape are produced with different geometric makeups at the bottom of the tool. Square ends are the most common form, and are really great for creating pockets, grooves, profile/contour cuts, lettering, and drilling operations. A ball or round end is best used when routing anything in 3D. V bottoms are typically used for creating and engraving simple and complex lettering but can also be used for creating a chamfer along the edge of a part.
calculating feeds and speeds using chipload
Chip load is the actual thickness of a single chip produced by the cutting tool for each revolution of the cutter. This same size chip load should be produced for every flute on the cutter as it rotates, engaging the substrate being cut. This is the measurement that all feed/speeds calculations are based on.
A rotating cutter generates friction as it engages and moves through the cutting material, producing heat. A portion of this heat is transferred through the chips that fly out of the cut. A larger chip load reduces the amount of heat produced, but also provides more stress on the cutting tool. Every material has its own ideal chip load range that balances heat transfer with cutter stress.
A basic chart is provided at the end of this manual showing the ideal chip load range for specific materials utilizing various diameter tools. Read through this chart as it will also explain recalculating chip loads at more aggressive depths of cuts.
How do I calculate chip load?
To calculate chip load, use the following formula:
Chip Load = Feed Rate / (Spindle RPM x Number of Flutes)
All Techno CNC machines are equipped with high frequency air cooled spindles allowing operators to run at precise spindle seeds without having to worry about aggressive cutting slowing the spindle motor down. This gives Techno CNC machinists precise speed control optimizing any application performed on the machine.
For calculating the feed rate for your machine, use the following formula:
Feed Rate = Spindle RPM x Chip Load x Number of Flutes
When choosing a spindle speed to run at, the operator must take into account the maximum feed rate their machine is capable of cutting at. If the calculated feed rate using a specific spindle speed is higher than the feed rate that the machine is capable of, through this formula, we know that we must use a slower spindle speed in order to produce a feed rate that is acceptable for the machine being used. For more information about the max speeds for your machine, please contact Techno CNC’s technical support team.
Chiploads:
Chip loads are based on material thickness of average size for cutting edge length of tool. These recommendations do not apply to thicker material or Techno CNC tools with long cutting-edge lengths. These chip loads are only a recommended starting point and may not accommodate all circumstances. Therefore, tooling damage may still occur and use of this chart does not warranty against tool breakage. We strongly encourage you to consult us directly on new tool applications. All parameters and settings are calculated with the intention of using inches per minute as the units for feed rate.
RPM Selection
The general operating RPM for Techno CNC Tooling is between 12,000 – 24,000 RPM. Usually, the higher the spindle RPM, the better the edge finish becomes. However, the higher the spindle speed, the more heat is produced between the tool and the workpiece. In a production environment, your goal is to run as fast a feed rate as possible while still retaining good cut quality and tool longevity. Test cuts should be conducted on new materials prior to putting tools in a production setting.
Most popular Router Bits
1. SW141434-2D Solid Carbide Down-Cut Bit
Best for: Wood and plywood
Key Benefit: Down-cut flutes push chips downward, producing a clean top surface without fraying.
Use Case: Ideal for cabinetry, furniture components, and laminated panels.
2. CM141478 Compression Bit
Best for: Laminated plywood and MDF
Key Benefit: Combines up- and down-cut flutes, compressing material fibers for clean edges on both sides.
Use Case: Essential for double-sided finish work where both edges must be clean.
3. PL3838118-1U O’Flute Up-Cut Bit for Plastics
Best for: Acrylic, PVC, and other soft plastics
Key Benefit: Polished flutes help with chip evacuation, reducing heat and preventing melting.
Use Case: Acrylic signs, plastic enclosures, anything ‘plastic’ and decorative panels.