The Ultimate Guide To Router Bits: Everything You Need To Know

types of router bits

What are router bits and their application?

Router bits are the tools used for cutting and carving various materials, typically categorized into handheld routers and CNC router bits. They are widely used in woodworking, metalworking, stoneworking, and other industries. Router bits are usually used for advertising making, furniture making, handicraft carving, gold and silver jewelry engraving, electronic products processing, mold making, etc. In our daily life, many exquisite handicrafts and furniture are made with router bits. Now let’s explore the different types of router bits and their uses.

cnc router bits application

Router Bit Materials:

Router bits are essential tools in cutting processes, whether on conventional machine tools or advanced CNC (Computer Numerical Control) machines, CNC machining centers, and flexible manufacturing systems (FMC). The development of these tools directly impacts productivity and machining quality. 

The material, structure, and geometric shape of router bits are three key factors determining their cutting performance. Among them, the choice of router bit’s material has a significant impact on tool life, machining efficiency, machining quality, and machining cost. 

router bits

There are five main types of commonly used router bit materials.

HSS: 

High-speed steel (HSS) is a type of high-alloy tool steel that contains a higher amount of alloying elements such as W, Mo, Cr, and V, with a carbon content of 0.7% to 1.05%. High-speed steel has high heat resistance, with a cutting temperature of up to 600°C. Compared to carbon tool steel and alloy tool steel, high-speed steel can double the cutting speed. 

High-speed steel has good toughness and formability, making it a soft metal. However, high-speed steel also has disadvantages such as poor wear and heat resistance. Common CNC router bits that use high-speed steel are foam cutters for machining foam.  They are the best router bit for cutting foam.

Solid carbide:

also known as tungsten carbide, is characterized by high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance. It delivers exceptional performance, particularly in hardness and wear resistance, maintaining these properties even at temperatures up to 500°C and retaining high hardness at 1000°C.   

Carbide is widely used as tool material, such as wood-turning tools, milling cutters, planers, drills, and boring tools. The majority of woodworking tools are made of tungsten carbide.                                                                                                                                                carbide router bits

Polycrystalline diamond:

Diamond, as a super-hard tool material, has been used in cutting processes for centuries. Diamond cutting tools are known for their high hardness, high compressive strength, good thermal conductivity, and excellent wear resistance, allowing for high machining precision and efficiency in high-speed cutting operations. The hardness of polycrystalline diamond (PCD) can reach 8000HV, which is 8 to 12 times that of cemented carbide. 

PCD router bits materials include single crystal diamond (available in natural and synthetic forms, with natural diamonds being expensive and partially replaced by synthetic diamonds), polycrystalline diamond (PCD), polycrystalline diamond, and cemented carbide composite blades (PCD/CC), and chemical vapor deposition (CVD) diamond. They can be used for cutting hardwood, stone, and composite materials. Common PCD tools include PCD straight router bits, PCD spiral router bits, and PCD compression router bits, as well as diamond pre-milling cutters for edge banders.

PCD router bits

 

Cotated: 

Coated refers to applying a layer of high-hardness, high-wear-resistant metal compound, several micrometers thick, on the substrate of cemented carbide or high-speed steel. This can extend the tool’s lifespan significantly. Tools with coated protection can last nearly 10 times longer than those without coatings. Common coatings for tools include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), aluminum oxide (Al2O3), and titanium aluminum nitride (TiAlN).

CBN:

Cubic Boron Nitride (CBN) is a new type of superhard tool material produced under high temperatures and high pressure. Its hardness is second only to diamond, reaching 7000~8000HV.

Router Bits Types And Uses:

There are various types of router bits available, suitable for different materials and processing requirements. Below is a summary of the types of router bits for your reference.

Based on the shapes, router bits can be classified as follows:

  1. Flat end mill: As the name suggests, this type of router bit has a flat bottom. It is mainly used for cutting materials and rough machining.
  2. Ball nose: The bottom of the cutter is shaped like a ball, including a tapered ball nose. Mainly used for surface carving, relief carving, flat carving, 3D carving, and other precision machining tasks.
  3. V-Bit:  The bottom is pointed and mainly used for V-shaped carving of materials, such as engraving, chamfering, lettering, line carving, advertising carving, etc.
  4. Bull nose: The bull nose bits have a similar appearance to the flat end mill, with both featuring a flat bottom design. However, the bull nose cutter differs in that its bottom has a rounded edge with an R angle instead of a pointed edge. Bull nose cutters are suitable for semi-precision machining tasks, such as foam carving.

router bits types

Based on the types of material being processed, router bits can be categorized as:

  1. Woodworking router bits: Used for cutting veneered panels such as plywood, particle board, and MDF board. Good chip removal is essential. They are mostly made of solid carbide.
  2. Metal cutting router bits: Used for cutting metals like aluminum and steel. Because cutting hard metals generates high heat, coatings are generally needed to extend the tool’s lifespan.
  3. Foam cutting router bits: Used for cutting EPS, EVA, and polyurethane foam, commonly used in mold making. It needs to be used for deep cavity machining, so it is a relatively long router bit. Foam is light, so the spindle speed should be slower to avoid vibration. There are usually many flutes, typically 4, 6, or 8 flutes.                                                                                                                                                                  best router bit for cutting foam
  4. Router bits for composites: Such as PCD tools. Composite materials are hard and require even harder materials for cutting.
  5. Stone router bits: Cutting marble, granite, and bluestone. Stone is very hard, so stone-cutting tools also need to use diamonds. Diamond is brazed onto the blade, which is called Brazing Diamond Bits. router bits for stone
  6. Plastic cutting router bits: Used for cutting PVC, acrylic, and other plastics. The material being cut is hard, and sticky, and tends to overheat the tool, requiring high speeds, typically with a single flute.
  7. PCB router bits: Used for cutting printed circuit boards. Circuit boards are super hard and they are an insulating material. Such tools require super-hard corn cutters. types of router bits

 

According to the shape of the blade, router bits can be divided into:

  1. Straight Flute: offers greater cutting force and faster speeds.
  2. Spiral Flute: provides better chip removal and smoother finishing.
  3. Chip Breaker router bits:  the cutting edge has serrations.

different router bits

Router bits can be classified based on the number of flutes:

  1. Single Flute
  2. Double Flutes
  3. Triple Flutes
  4. Four flutes

The number of flutes affects cutting speed and efficiency. Single flute router bits are beneficial for chip removal, such as with acrylic and aluminum, and are suitable for viscous materials. Double-flute router bits are one of the most widely used cutting tools. Woodworking router bits can utilize up to four flutes. For router bits with three or four flutes, the larger size results in smoother finishes with the same rotation speed.

Based on the spiral direction, router bits can be categorized as:

  1. Up-cut: The flute spirals upward, also referred to as right-hand rotation router bits. Chip removal is directed upward, resulting in a rough top surface of the wood board and a clean bottom surface. Suitable for non-laminated panels, and bare boards. Economical and durable, requiring only one side to be smooth. 
  2. Down cut: flute spirals downward, also known as left-hand rotation router bits. Chip removal is directed downward, resulting in a clean top surface and a rough bottom surface. It is especially suitable for processing thinner sheets that are not easy to adhere to or fix. Utilizes the downward force of chip removal to securely fasten the workpiece to the table, preventing movement during processing.
  3. Compression flute: A combination of up-cut and down-cut. The compression bits can ensure smooth surfaces on both sides without burrs, preventing edge chipping. They are particularly suitable for high-precision processing of melamine laminated boards, such as MDF, plywood, and particle board.  Because the veneer is melamine, which is very brittle and hard, and the chip removal is in the middle, generating high heat in the middle, the quality of the tool material must be good.

router bits best

Router Bit Dimensions Explained:

Here are several parameters about router bits that you should know:

  1. Shank Diameter: The diameter of the shank. It should match the diameter of the collet.
  2. Cutting Edge Diameter (CED): The diameter of the cutting edge. 

  It is related to the thickness of the workpiece and the desired cutting speed. Generally, a larger blade diameter allows for deeper material cutting and higher efficiency. However, it also produces more wood chips, resulting in more material waste. Therefore, a larger flute diameter is not always better. It is very important to choose the appropriate blade diameter based on actual processing needs to achieve the desired processing effect while also saving costs.

  1. Cutting Edge Length (CEL): The length of the cutting edge. 

It is generally higher than the processing depth by a few millimeters to ensure that the workpiece is fully processed. However, it should not be too high, as this can cause tool deflection and damage, leading to increased costs.

  1. Overall Length (OVL): The total length of the router bits. 

It is the cutting-edge length plus the shank length. Longer bits are generally used for deep cavity machining.

wood router bitsHow To Select A Router Bit For Your Job

The selection of router bits is closely related to the material being processed, the depth of cut, and the desired surface finish. Choosing the right router bits can improve processing efficiency and quality.

  1. For cutting plywood and laminated boards, it is recommended to use T007 TCT 3 straight flutes with a chip breaker. For TCT (Tungsten Carbide-Tipped) router bits, the cutting edge is made of tungsten carbide, while the shank is made of tool steel, making it relatively cheaper than integral tungsten carbide, economical and efficient cutting. They are ideal for panel furniture and have become popular tools in recent years.
  2. For MDF and melamine boards, it is recommended to use T008 TCT 3 flutes straight flute router bits, good cutting performance, and excellent surface finish.
  3. For cutting particle boards, it is recommended to use T011 compression cutters with chip breakers. Under proper use, a single bit can cut approximately 100 pieces of board.                                                                                                                                                   The above TCT router bits are very popular as the best router bits for CNC wood nesting.router bits woodworking
  4. For cutting acrylic, it is recommended to use a single flute CNC router bit designed specifically for acrylic. This acrylic router bit offers smoke-free and odor-free processing, fast speeds, and high efficiency. It does not stick to chips, resulting in a smooth and flat surface. If a frosted effect is desired on the processed surface, it is recommended to use double or triple-flute acrylic router bits.
  5.  For foam cutting, it is recommended to use HSS foam cutters.                                           eps foam router bits
  6. For cutting aluminum, it is recommended to use a single flute router bit specially designed for aluminum. The aluminum router bit prevents material from sticking to the tool during processing, allowing for fast speeds and high efficiency.
  7. For precision small-scale relief carving, it is recommended to use round-pointed bottom and conical ball nose router bits.
  8. For large-scale deep relief carving of cork, density boards, solid wood, PVC, and acrylic, it is recommended to use ball nose router bits.
  9. For cutting requirements of no burrs on the top and bottom surfaces, it is recommended to use single-flute, double flutes, or triple flutes compression bits.
  10. For 3D carving, recommended to use 3D carving router bits
  11. For rough machining and lock hole machining, it is recommended to use roughing router bits with chip breaker and multi-stripe end mills.
  12. For super hard solid wood or particle boards, it is recommended to use diamond router bits. diamond router bits
  13. For cutting density boards (used for advertising mold opening), it is recommended to use double flutes spiral end mills, for cutting bare boards.
  14. For stone processing, it is recommended to use diamond router bits for stone.

How To Properly Use Router Bit

1. Recommended RPM, speed, and feed rate:

  • For cutting wood and plastic, high speed is needed, generally set at 18000-24000 RPM for better surface finish.
  • For cutting aluminum, which is harder, the speed should be reduced, typically set at 12000 RPM. 
  • For foam processing, the RPM should generally not exceed 6000.
  • The speed depends on how deep you want to cut by one path.
  1. Select the appropriate CNC router bits for different materials. Generally,  the tools are clockwise rotation.
  2. Use high-precision collets. If any wear or other issues are preventing them from meeting the configuration requirements, they should be replaced immediately.
  3. When clamping the router bit, it is important to avoid clamping any debris and ensure that the clamping depth meets the requirements. For example, for a 1/2-inch (12.7mm) shank, the clamping depth should reach 24mm to ensure its required load-bearing capacity. In general, the clamping depth should be at least 4/5 of the length of the tool shank.
  4. Select the appropriate speed and feed rate based on the size of the CNC router bits and the amount of material being processed, and maintain a steady feed rate without interruptions during cutting.
  5. Replace the CNC router bit promptly when it becomes dull.
  6. Users should pay attention to safety protection when using CNC cutting tools for processing.

best cnc router bitsHow To Change A Router Bit

When the cutter becomes black, smokes, produces poor results, or creates burrs, it should be replaced promptly to avoid hazards. When replacing the cutter, first stop the machine, loosen the screws, remove the damaged bit, replace it with a new one, calibrate using an auto tool setter, and then resume operation.

Router Bit Maintenance: 

  1. When not in use, remove them from the router and clean off any wood debris. Apply a rust inhibitor spray to prevent rust.
  2. When storing router bits, ensure they are kept in a dry environment to prevent moisture and rust.
  3. How to sharpen CNC router bits

  Follow these steps:

  • Select a suitable grinder and grinding wheel (type, model).
  • For new tools, measure the main geometric parameters and record them, 
  • Input the grinding wheel data first, then input the tool data.
  • After grinding, measure the main parameters of the tool and make corrections based on the grinding standards.

Note: HSS router bits are less sensitive to collisions due to their good toughness. However, carbide router bits are hard and brittle, making them sensitive to collisions, which can cause the blade to chip. Therefore, during the grinding process, extreme care must be taken with carbide cutters to prevent tool-to-tool collisions or tool dropping.

Router Bit Maintenance

How To Make Specific Profiles With Router Bits?  

To quickly create shapes on wooden panels, some classical plunge router bits are commonly used. These router bits can be used to make cabinet doors.

  1. Straight Router Bit: Used for grooving.
  2. Core Box Router Bit: Used for making round grooves.
  3. Bottom Cleaning Router Bits: Used for grooving and bottom cleaning.
  4. Flush Trim Router Bits: Used for trimming straight edges.
  5. Round Over Router Bit: Used for rounding edges.
  6. Dovetail Router Bit: Used for woodworking joints.
  7. T Slot Cutters: Used for cutting T-slots for inserting edge strips.
  8. V Groove Router Bit: Used for cutting V-grooves and folding straight boards.
  9. Chamfer Router Bits: Used for chamfering edges.

Router Bits profile

Summary:

The above is a summary of router bits knowledge based on our understanding and industrial experience. There is a wide variety of router bits available on the market, and different machines and processing materials have different requirements. Therefore, it is important to choose the right tool according to the actual situation and use it correctly to achieve good results, save costs, and maximize efficiency. We hope this is helpful for your job!

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