Router Bits Explained: Types, Materials, and Uses

Router bits are the interchangeable cutting tools that determine what your router can do. From simple edging to complex joinery, the right bit transforms a basic router into a versatile woodworking machine. This guide explains the common types, materials, coatings, and how to choose the best bit for your project.

Types of Router Bits

Router bits come in many profiles, each designed for a specific cut. Here are the most common types you will encounter.

• Straight bits: These have a flat cutting edge and are used for cutting grooves, dadoes, and mortises. They come in various diameters and lengths.
• Flush trim bits: With a bearing at the top or bottom, they trim a workpiece flush with a template or an existing edge. Ideal for pattern work and laminate trimming.
• Roundover bits: These create a rounded edge, softening sharp corners. The radius of the bit determines the curve size.
• Chamfer bits: They cut a beveled edge at a set angle, commonly 45 degrees, for decorative edges or to create a clean joint.
• Dovetail bits: Shaped like a fan, they cut dovetail joints used in drawer construction and boxes. The angle varies, typically 7 to 14 degrees.
• Rabbeting bits: These cut a recess along the edge of a board, often for cabinet backs or drawer bottoms. They have a bearing to control depth.
• Cove bits: They create a concave profile, the opposite of a roundover, for decorative edges or to make a cove molding.
• Roman ogee bits: A classic decorative profile with a combination of curves, used for edging and trim work.

Other specialty bits include keyhole, slot cutting, and raised panel bits. Each serves a niche purpose, but the ones above cover most woodworking needs.

Shank Sizes and Materials

The shank is the part that fits into the router collet. Shank size affects stability and compatibility.

Shank Sizes

• 1/4 inch: Common on smaller routers and trim routers. Lighter and less expensive, but more prone to flexing under heavy loads.
• 1/2 inch: The standard for full-size routers. Thicker shank provides greater rigidity, reducing vibration and improving cut precision.
• 8mm: Sometimes found on European routers; check your collet compatibility.

Always use a bit with a shank that matches your router's collet. Some routers have interchangeable collets.

Materials

• High-Speed Steel (HSS): HSS bits are affordable and can be sharpened easily. They dull faster, especially on hardwoods and abrasive materials. Good for occasional use and softwoods.
• Carbide (Tungsten Carbide): These bits last much longer and withstand high heat. They are ideal for hardwoods, plywood, and MDF. The cutting edges are often brazed onto a steel body. Carbide is the preferred choice for serious woodworkers.

Coatings

Some bits have special coatings to reduce friction and heat.

• Titanium Nitride (TiN): A gold-colored coating that increases hardness and lubricity, reducing resin buildup.
• Titanium Aluminum Nitride (TiAlN): A dark coating that offers even higher heat resistance, suitable for abrasive materials.
• Diamond-like Carbon (DLC): A black coating that provides low friction and high wear resistance.

Coatings help the bit stay cooler and cleaner, extending its life. However, they add to the cost.

Choosing the Right Bit

Selecting the correct bit depends on the task, material, and desired finish. Here is a practical guide.

Match Bit to Task

• For dadoes or grooves: use a straight bit with the same width as the slot.
• For trimming laminate: use a flush trim bit with a bearing.
• For softening edges: use a roundover bit with the desired radius.
• For decorative edges: use a chamfer, cove, or Roman ogee bit.
• For dovetail joints: use a dovetail bit with the correct angle.

Consider Material

• Softwoods (pine, fir): HSS bits are fine, but carbide lasts longer.
• Hardwoods (oak, maple): carbide is recommended to maintain sharpness.
• Plywood and MDF: carbide with a coating helps resist wear and resin buildup.

Shank Size

For heavy cuts or large bits, choose a 1/2 inch shank for stability. For light trimming, a 1/4 inch shank works.

Quick Reference Chart

Always test on scrap material first to ensure the cut is correct.

Maintenance and Safety

Proper care extends bit life and prevents accidents.

Maintenance

1. Clean bits after each use with a soft brush or a bit cleaner to remove pitch and resin.
2. Store bits in a protective case or rack to avoid chipping the edges.
3. Sharpen dull bits. Carbide bits can be sharpened with a diamond wheel, but many prefer to replace them.
4. Inspect bits for cracks or broken carbide before each use. Discard damaged bits.

Safety

• Always unplug the router before changing bits.
• Use the correct collet size and tighten securely.
• Wear safety glasses and hearing protection.
• Feed the router against the rotation direction to avoid kickback.
• Use a router table for larger bits or when making non-through cuts.
• Never force a bit through the material; let the tool do the work.

Following these guidelines keeps you safe and your bits performing well.

FAQ

What is the difference between 1/4 inch and 1/2 inch shank router bits?

1/2 inch shanks are thicker and more rigid, reducing vibration and improving cut quality. They are preferred for heavy-duty work. 1/4 inch shanks fit most palm routers and are fine for light trimming. Always match the shank size to your router collet.

Are carbide router bits better than HSS?

Carbide bits stay sharp longer and handle heat better, making them ideal for hardwoods and abrasive materials like plywood. HSS bits are cheaper and easier to sharpen, but dull faster. For most woodworking, carbide is the better investment.

How do I know which router bit to use for a specific task?

Match the bit profile to the desired cut: straight bits for dadoes, flush trim for copying, roundover for edges, and dovetail for joints. Consider material hardness and shank size. Refer to the chart in this guide for a quick reference.

For more detailed guidance, check the current price on Amazon for a router bit set that covers common profiles.