A CNC Router bit selection guide for your next project

Router bits are an essential component of any 3-axis CNC router, and choosing the right size and type of bit for your specific application can make a big difference in the quality and efficiency of your work. Let’s explore some of the most common types of router bits and how you can make a good selection for your project.

Router Bit Sizes-

Router bits come in a wide range of sizes, and choosing the right size is essential for achieving optimal results. The most commonly used sizes for 3-axis CNC routers include 1/8 inch, 1/4 inch, 1/2 inch, and 3/8 inch. These sizes are selected based on the thickness of the material being worked on and the size of the cut required. Another important factor in selecting your router bit is that of the cutting length of the bit, note this is different than the overall length.

1/8 Inch Router Bits: These bits are fantastic at inlays as well as finish passes. Using a small bit like a 1/8 gives you the ability to do your initial cuts in an onion skin fashion with a larger, faster bit and then do your final pass with the 1/8. Imagine you have a 1/2 sheet of plywood that is exactly .5″ thick and you want to cut many small parts. You could use a 1/4″ bit do a fast cut to a depth of .48, this would preserve your vacuum and allow you to cut very quickly. Then you could come in with the 1/8 and do a final cut to your final depth of .5″ and the chance of your parts moving would be greatly diminished.

1/4 Inch Router Bits: These bits are good for their combination of strength and relatively small size. The 1/4″ size gives you the freedom to experiment with faster cuts without the fear of potentially harming your machine. A 1/4″ is one of the sizes that is just small enough that it will break if you push too hard, rather than get caught in the material. Using a 1/4 as a finish pass on larger parts is a good technique as is cutting things like drawer dados. This size will not create too much friction when cutting.

3/8 Inch Router Bits: These are your go-to when cutting large parts out of sheet goods such as plywood or mdf. The 3/8″ will not typically break easily and you will want to keep an eye on your cut quality as a metric of your bit becoming more dull. Pocketing and full depth cuts are also great options with the 3/8″ bit. This is the most common size when cutting cabinet goods in 3/4″ plywood at full depth.

1/2 Inch Router Bits: These bits are the most commonly used size for general-purpose cutting and are suitable for a wide range of materials, including hardwoods and softwoods. They are ideal for making straight cuts, grooves, and decorative edges. Their size has the clear advantage when doing pockets and deep cuts in harder materials such as walnut, plastics, and metals.

Router Bit Types

There are several types of router bits that are commonly used for different applications with 3-axis CNC routers. Some of the most common types include:

Straight Router Bits: These bits are used for making straight cuts and shaping edges. They come in a variety of sizes, ranging from small trim bits to large panel bits, and are suitable for a wide range of materials. These are an absolute must have in your collection of bits as they pair extremally well with vacuum hold down techniques. By applying lateral force, as opposed to upward or downward force, they can dramatically increase the chances of your smaller parts staying sealed with the vacuum below. These are highly versatile and can be used on wood, plastic and aluminum.

Profile Router Bits: These bits are used for creating decorative edges and profiles on furniture pieces, such as moldings and trim. They come in a variety of shapes and sizes, including round-over, ogee, and cove bits. These are great options for the cabinet industry and can save you a finishing step on the back end of things like doors, rails, and other unique profiles.

Cove Router Bits: These bits are used for creating a rounded edge on furniture pieces, such as table tops and cabinet doors. They come in a variety of sizes and shapes, including large and small cove bits, and are ideal for adding a decorative touch to your work.

Dovetail Router Bits: These bits are used for creating dovetail joints, a type of joinery commonly used in furniture making. They come in a variety of sizes, ranging from small bits for creating small dovetails to larger bits for making large joints.

V-Groove Router Bits: These bits are used for creating V-shaped grooves, such as in raised panel doors or sign-making. They come in a variety of sizes and are ideal for adding a decorative touch to your work.

Material Types-

High-Speed Steel (HSS) Router Bits are a type of cutting tool commonly used in woodworking and metalworking applications. They are made from high-speed steel, a type of tool steel that is designed to maintain its hardness and cutting ability at high temperatures. HSS router bits are known for their durability and versatility, making them a popular choice for many woodworkers and metalworkers.

Advantages of HSS Router Bits:

1. Durability: HSS router bits are made from high-speed steel, which is a hard and durable material that can withstand heavy use and high temperatures. This makes them ideal for high-speed and high-volume cutting applications.

2. Versatility: HSS router bits can be used on a wide range of materials, including softwoods, hardwoods, laminates, composites, and even metals. They are also suitable for a wide range of cutting applications, from straight cuts to decorative cuts.

3. Precision: HSS router bits are designed to maintain their sharpness and accuracy over time, which makes them ideal for precise cuts and intricate designs. They also have a longer lifespan than other types of router bits, making them a cost-effective option in the long run.

4. Affordability: Compared to other types of router bits, such as solid carbide or diamond-tipped bits, HSS router bits are relatively affordable. This makes them a popular choice for woodworkers and metalworkers who need high-quality cutting tools at a budget-friendly price.

Disadvantages of HSS Router Bits:

1. Limited Performance: While HSS router bits are durable and versatile, they are not suitable for the toughest materials and applications. For example, they may dull faster when cutting materials such as aluminum or stainless steel.

2. Maintenance: HSS router bits need to be regularly sharpened to maintain their cutting ability and accuracy. This requires additional time and resources, and may not be feasible for those with limited workshop space or tools.

Carbide End Mills- These are a type of cutting tool used in metalworking applications. They are made from a material known as tungsten carbide, which is a mixture of tungsten and carbon that provides a hardness and strength that is much higher than high-speed steel (HSS). This makes carbide end mills ideal for cutting and shaping metal parts with high precision and accuracy.

Advantages of Carbide End Mills:

1. Hardness: The tungsten carbide material used to make carbide end mills provides a hardness that is much higher than HSS. This means that carbide end mills can withstand heavy use and remain sharp for longer periods of time, making them ideal for high-volume metalworking applications.

2. Precision: The high hardness of carbide end mills provides a high level of precision and accuracy when cutting metal parts. This makes them ideal for applications that require tight tolerances and precise cuts, such as in the aerospace and medical industries.

3. Heat Resistance: Carbide end mills can operate at higher temperatures than HSS end mills, making them ideal for high-speed cutting and milling applications. This helps to reduce the risk of tool failure and increase the lifespan of the end mill.

4. Wear Resistance: The tungsten carbide material used in carbide end mills provides excellent wear resistance, making them ideal for use in harsh environments. This helps to extend the lifespan of the end mill and reduce the need for frequent replacements.

Disadvantages of Carbide End Mills:

1. Cost: Compared to HSS end mills, carbide end mills are significantly more expensive. This can make them a less attractive option for woodworkers and metalworkers who need a large number of cutting tools for their projects.

2. Brittleness: Although carbide end mills are extremely hard and durable, they can be brittle and prone to breaking if not used properly. This makes them less suitable for roughing or aggressive cutting applications.

3. Limited Cutting Range: Carbide end mills are designed for cutting metal parts and are not suitable for use on other materials, such as wood or plastic. This limits their versatility and may require the use of multiple cutting tools for different applications.

Coating on End Mills-

Coated end mills and non-coated end mills both have their own unique benefits, depending on the application they are being used for. Here are some of the key benefits of each type of end mill:

Benefits of Coated End Mills:

1. Increased Longevity: Coatings such as TiN (Titanium Nitride), TiAlN (Titanium Aluminum Nitride), and AlTiN (Aluminum Titanium Nitride) help to increase the lifespan of the end mill by reducing friction and heat buildup during cutting. This can result in fewer tool failures, longer cutting life, and less downtime for tool changes.

2. Improved Lubricity: Coatings like TiN, TiAlN, and AlTiN can help to reduce friction between the end mill and the workpiece, resulting in improved lubricity and cutting performance.

3. Increased Hardness: Coated end mills can be harder and more durable than non-coated end mills, making them ideal for tough cutting applications.

4. Improved Surface Finish: Coatings like TiN and TiAlN can help to improve the surface finish of the cut, making them ideal for precision cutting applications.

Benefits of Non-Coated End Mills:

1. 1. Cost Savings: Non-coated end mills are typically less expensive than coated end mills, making them a cost-effective solution for many cutting applications.

   2. Versatility: Non-coated end mills can be used on a variety of materials, including steel, aluminum, and plastic. This makes them a versatile solution for many cutting applications.

   3. Better for Certain Applications: In some cases, non-coated end mills are better suited for certain applications than coated end mills. For example, non-coated end mills are often preferred for roughing operations, as they can better handle the heavy loads and high speeds associated with this type of cutting.

Visit http://frontrangecnc.com/shop/ for a assortment of the most popular router bits.

Still have questions about router bit selection? Send us a note and we will be happy to offer some guidance for your project!