Router Bit Glossary: Router Bit Terms Explained

Router Bit

Pieces that attach to a router tool, mainly used for cutting and carving wood. Router bits come in a variety of shapes and sizes.

CNC Router Bit

Router bits designed to withstand the higher speeds of CNC router machines. Many CNC router bits can also be used in tabletop and handheld routers.

Router Bit Sets

A number of router bits used together to achieve a specific woodworking task. For example the Tambour Door Router Bit Set includes 3 router bits used create tambour doors for desks or appliance garages. Sets can also be simply collections of useful bits.

Flutes

A router bit flute is the groove that contains the cutting edge and carries chips away from the cut. The number and design of the flutes affect cut quality and performance.

Shank

A router bit shank is the smooth, non-cutting portion of the bit that fits into the router collet. It holds the bit securely while transferring power from the router to the cutting edges.

Bearing

A router bit bearing is a small wheel mounted on the bit that acts as a guide. It follows an edge, template, or surface to help control the depth and shape of the cut.

Collet

A collet is the part of a router that grips and holds the shank of the router bit. It keeps the bit securely centered while it spins.

Tool Extenders

A tool extender is an accessory that increases the reach of a router bit by extending it farther from the collet. It provides additional clearance and cutting depth but should be used carefully, as increased reach can reduce rigidity and increase vibration.

Brazed Carbide / Carbide Tipped

A cutting tool design in which a carbide cutting edge is permanently bonded to a steel body using a brazing process, providing a durable and cost-effective alternative to solid carbide tools.

Solid Carbide

Solid carbide bits can use harder, longer-wearing carbide than brazed tools because no high-heat brazing process is required during manufacturing.

Milling

The process of shaping material by feeding a workpiece past a rotating cutter, or by moving a rotating cutter across a fixed workpiece.

Speed

How fast a router bit spins, measured in revolutions per minute (RPM).

Feed

How fast the tool or material moves through the cut, measured in inches per minute (IPM).

Chip Load

The amount of material removed by each flute during a cut.

Anti-Kickback Design

Offers some degree of safety to the end-user because it limits the ‘chip-thickness’ of the material being cut. In other words, the cutting tool will take less of a ‘bite’, thereby decreasing the likelihood of a kickback.

Router Bit Maintenance

Regular cleaning, inspection, and care that help router bits cut cleaner, last longer, and operate safely. [Read more.]

Router Bit Safety

Safe operating practices that help prevent kickback, tool damage, and injury when using router bits. See our Safety Guidelines / Lineamientos de Seguridad.

Straight Plunge Bits

Straight plunge bits are used for routing straight grooves, rabbets, dados, joints, mortises, trimming material or making a general cut.

Spiral Plunge Bits

Spiral bits are designed like a drill and are used to make deep cuts to the surface of your wood piece.

Upcut Bits

Upcut bits are the go to choice where having a clean bottom surface or getting maximum chip evacuation on deeper profile cuts is most important.

Spiral Down-Cut Bits

A downcut bit is the perfect choice for cuts where having a clean top surface, like creating non-through pockets, is necessary.

Compression Spiral Bits

Compression bits are the best of both worlds, containing an upcut and a downcut grind on the same bit.

Learn more about Downcut, Upcut, and Compression Bits.

Ball Nose & Tapered Ball Nose Bits

Unlike standard spiral bits, Ball Nose bits are designed to machine smooth 3D contours and rounded surfaces. Tapered Ball Nose bits add strength and rigidity for finer detail and deeper carving with less deflection.

O-Flute Bits

O-Flute Bits are router bits designed for cutting plastics, aluminum, and other soft materials. Their single flute efficiently clears chips and reduces heat buildup, helping produce cleaner cuts and better edge finishes.

Spoilboard Surfacing Bits

CNC bits designed to flatten spoilboards and other surfaces, ensuring a level work area and consistent cutting depth across the entire project. Read Flattening and Spoilboard Bits: How to Get a Smooth, Level Surface

Aluminum and Non-Ferrous Metals

Aluminum, brass, copper, and other non-ferrous metals require sharp cutting edges and efficient chip evacuation to prevent heat buildup and chip welding. Router bits designed for these materials typically feature polished flutes and specialized coatings that produce cleaner cuts and extend tool life.

See our articles, Tips for Working With Aluminum on Your CNC Router Table, and Best CNC Router Bits for Cutting Aluminum.

Carbon Fiber (CFRP)

Carbon fiber is lightweight and extremely strong, but its abrasive fibers can quickly wear down ordinary cutting tools. Router bits designed for carbon fiber use specialized carbide grades and geometries that resist wear, minimize fraying, and produce cleaner edges.

Fiberglass and Abrasive Materials

Fiberglass, G10, phenolic, and similar materials are highly abrasive and can rapidly dull standard router bits. Specialized cutting tools are designed to withstand this wear while reducing edge chipping, delamination, and premature tool failure.

Foam Cutting Router Bits

Foam materials are soft and easy to cut, but conventional bits can tear the material or leave rough edges. Foam-cutting router bits typically feature large flutes and geometries designed to remove material efficiently while producing smoother surfaces and cleaner contours. Learn How to Choose the Right Bit for Foam Cutting.

Honeycomb Materials

Honeycomb panels present a unique challenge because much of the material consists of empty space rather than solid stock. Router bits designed for honeycomb materials help reduce tearing, crushing, and edge damage while producing clean, accurate cuts.

Plastics & Acrylics

Plastics and acrylics can melt, chip, or weld material back into the cut when heat builds up. Router bits designed for these materials often feature polished O-flute geometry that clears chips efficiently, reduces friction, and produces smoother edges.

Deeper dives: Best Blades and Bits for Cutting Plastic and Spiral ‘O’ Flute CNC Router Bits Produce Super-Clean Cuts in Plastic, Nylon, Polycarbonate & More

Solid Surface Materials

Solid surface materials such as Corian® and similar countertop products require clean edges and smooth finishes for seamless fabrication. Router bits designed for these materials help reduce chipping while delivering the accuracy needed for trimming, profiling, and joint preparation. Learn more about Working with Solid Surface Materials.

Wood, Plywood, MDF and Melamine

Different wood-based materials present different cutting challenges. Solid wood can tear along the grain, plywood can splinter veneers, MDF produces fine dust, and melamine is prone to edge chipping. Specialized router bit geometries help improve cut quality and surface finish across these materials.

Combination Drill/Countersink Bits

Combination drill and countersink bits create both the pilot hole and countersink in a single operation, producing clean, consistent holes for flat-head screws while reducing machining time.

CNC Insert Tooling Systems

Insert tooling systems use replaceable solid carbide knives instead of permanently brazed cutting edges. When an insert wears out, you simply rotate or replace the knife, reducing downtime and lowering long-term tooling costs.

CNC Sanding Systems

CNC sanding systems automate surface preparation by sanding parts directly on the CNC machine, reducing manual labor and workpiece handling while producing smooth, consistent surfaces ready for finishing.

Box Joint (Finger Joint)

A box joint (also called a finger joint) uses interlocking square fingers to create a strong, glue-ready corner for boxes, drawers, and cabinets.

For production work, finger-joint bits are commonly used to create strong, repeatable interlocking joints.

Dovetail Joint

A strong joint created by carving one or more tapered, fan-shaped tenons into one piece of wood, which interlock with a series of mortises carved into the adjoining piece of wood. See Dovetail Joints: 5 Different Types and Their Uses.

Frame & Panel (Stile & Rail) Construction

Frame and panel construction joins vertical stiles and horizontal rails around a floating center panel, creating strong, stable doors and cabinet components. Specialized router bits cut the matching profiles in a single setup.

Lock Miter Joint

A lock miter joint uses interlocking profiles to create a stronger, self-aligning 90° corner than a standard miter joint. Lock miter router bits cut both mating pieces, making them ideal for boxes, cabinets, columns, and furniture.

Mortise & Tenon

The tenon, formed on the end of a "rail," is inserted into a square or rectangular hole (the mortise). Create a square mortise to receive the tenon with a Mortising Chisel & Drill Bit. Read more about Hollow Chisel Mortise Bits.

Rabbet Joint

A rabbet is a shoulder cut into the edge of a piece of (usually) wood. When viewed in cross-section, a rabbet joint is two-sided, and is open at either end. See 4 Ways to Make Rabbet Joints.

Tongue & Groove Joint

This joint is often used for wood paneling, flooring, parquet and other similar woodworks. The joint is used to fit 2 or more similar objects together edge-to-edge. Each piece has a slot or "groove" cut all along one edge, and a thin, deep ridge or "tongue" shaped on the opposite edge. They then fit together closely. See Mastering Woodworking with Tongue and Groove Router Bits.