Handy homeowners and do-it-yourselfers who have spent any time on improvement projects have encountered situations where only a router could “cut it,” literally and figuratively. This carpentry power tool provides a versatility that few other tools offer, good for mortising door hardware, custom-engraving, joinery, and a whole host of other essential functions. While they’re hardly limited to a handful of “cut and dry” categories, the most commonly used router bits are generally used for grooving, joinery, or rounding over edges. However, if you don’t know which router bit types serve which of these purposes, you could be leaving some of your tool’s potential on the table. Read on to discover the 10 router bits every DIYer can benefit from in the course of a woodworking project.
In this first section, we’ll highlight the most useful and common router bits used for grooving.
Straight bits are perhaps the most frequently used type of router bit since they can be used in a wide variety of applications. While in a class of their own, straight bits are usually used for cutting different types of square-shaped grooves. These grooves can be cut with the wood grain (the technical definition of a “groove”), against the wood grain (called a “dado”), or along the edge of wood to produce an L-shaped shoulder or “rabbet”. All of these cuts are often used for joining two pieces of material. For example, the mortise and tenon joint is a very popular and sturdy joining technique that can be easily made with a straight bit. Aside from joinery, straight bits can also be used for mortising in door hardware, or for grooving a channel where a decorative inlay can be inserted. They can even be used in place of more specialized bits (like rabetting, described below), which contributes to their impressive versatility.
They’re available in cut diameters ranging from 3/16-inch to 1½ inches and have either one or two ‘flutes’ (cutting arms) depending on how large or fine of a cut you need.
Best For: Making grooves, dados, mortises, and decorative inlays.
As the name implies, V-groove bits groove out a V-shaped profile in a piece of material, often to produce a decorative effect. V-groove bits can engrave designs in flat surfaces like signs or cabinet faces, create shallow grooves that run the length of a column (a style coined ‘fluting’), or even make ridges in panels to produce a beadboard effect. These bits come in a variety of diameters and V-groove angles that determine the width and depth of the groove. Some bits also have flat bottoms instead of sharp tips that limit the depth of the cut.
Best For: Making signs, fluted columns, and a bead-board appearance on panels.
The next three bits are primarily used for cutting adjoining notches to give two pieces of material strong, durable joints. Each bit doing so in its own unique way.
Rabbeting bits are designed to form an L-shaped shoulder or dado (square groove that runs against the grain) on the edge of a piece of material to form a rabbet joint. This occurs in cabinetry construction to make drawers and cabinet backs as well as to join the tops of cabinets to cabinet sides.
What distinguishes these bits from others (like a straight bit used for rabbeting) is the addition of a circular pilot bearing at the bit’s tip that acts like a spinning wheel riding along the edge of the piece being cut, guiding the cutting arm to the perfect depth. As a result, the width of the cut is determined by the size of the bearing, with a smaller bearing producing a wider cut. The most common sizes of rabbet bits are 1¼ inches and 1⅜ inches, and most bits come with several interchangeable bearings ranging from ⅜-inch to 1⅛ inches.
Best For: Creating rabbet joints to join two pieces of material.
4. Glue Joint
Glue joint bits assist joining two pieces of material by creating identical, adjoining tongues on the edge of both pieces. The notched cuts create plenty of surface area for gluing and form a tight-fitting joint that holds the pieces together while they’re being clamped. They’re available in two varieties: standard and mitered. The standard glue joint joins squared edges, while the mitered bit is made with a 45-degree angle to join two mitered edges.
Before you begin using these router bit types, know that they are meant to be used exclusively in a router table. Using glue joint bits in a hand-held router can result in uneven profiles or, worse, injury in the event that it binds up and kicks back on you.
These bits come in sizes ranging from 1⅜ inches to 2¾ inches and can be used on material from ½-inch to 1¼ inches thick.
Best For: Creating two adjoining joints that have a higher surface area for gluing.
5. Flush Trim
Flush trim bits are essentially straight bits with a pilot bearing that’s the same diameter as the flutes. The bearing at the tip guides the cutting arm perfectly around the edge of a surface, allowing you to trim overhanging material perfectly flush. You can use this for shelf edging, veneer trimming, or to smoothly join edges. They’re also great for duplicating curved patterns from a template. For trimming purposes, these bits can be used in a hand-held router, but a table-mounted router is best used when replicating patterns with a template.
Flush trim bits come in a variety of cutting arm lengths and diameters, but the most common are ½-inch diameter by a 1-inch length with a ¼-inch shank.
Best For: Trimming laminate and replicating patterns from a template.
Router bits are designed to serve three primary functions: To create wood joints, to plunge into the center of a piece for grooves or inlays, and to shape the edges of wood. The remaining five router bit types are all designed for the single purpose of shaping the sharp edges of lumber in different ways and for different purposes.
Not only are rounding-over bits the most commonly used type of edging bit, but they’re also perhaps only second to straight bits in how often they’re employed. They create a rounded profile to ease the sharp, 90-degree edge of a piece of wood. This gives the material a smoother, finished look. The eased edge can also help preserve paint and stain, since these finishes are more prone to chipping off sharp edges. Rounded-over edges are also smoother to the touch and less likely to cause injury to those that come into contact with it.
These bits come in two forms: single and double. Single rounding-overs create their profile on a single edge, producing a quarter-round effect. The double rounding-overs bits cut the bottom and top edge simultaneously, making a full half-round profile.
Best For: Smoothing out sharp edges to preserve a project’s finish and creating a decorative edge.
The chamfer bit is designed to produce a bevel cut on the edge of wood to serve either form or function—or both! The chamfer can provide an attractive edge profile and a professionally finished look on any project with flat edges, like counters and table tops. The beveling power can also be used to make perfect miter cuts on long, bulky, or curved material. Ripping perfectly straight miters on long boards with a table saw free from ugly saw marks or burns can be tricky, but using a chamfer bit in a router table can make exceptionally clean cuts. This is particularly useful when the angle of your miter needs to be spot-on, like when making multi-sided boxes. When you need to chamfer a curved edge, installing the bit onto a hand-held router allows the pilot bearing to seamlessly track the curved shape—a feat no saw can perform.
They come in sizes ranging from ⅛-inch to 2½ inches in diameter with angles between 11.25 and 45 degrees. This wide size and angle range are capable of creating miter joint angles from 22.5 to 90 degrees in material as thick as 1 inch.
Best For: Making decorative edges and joining two pieces of mitered material.
Cove bits produce a concave quarter-circle that’s essentially the inverse profile of the rounding-over shape. As opposed to the rounding-over, the quarter-circle of the cove is an indentation in, instead of an easing of, the 45-degree edge. It’s used for decorative purposes on the edges of window seals, stools, and tables, and can also be used to make moldings. Along with decoration, it can also be used with a complementary rounding-over bit to make adjoining edges for a rule joint—a popular technique for making a folding leaf for a table. Cove bits are available in 5/16-inch and 3/16-inch radiuses.
Best For: Creating a quarter-circle indentation in the edge of a piece for decoration or joinery.
9. Roman Ogee
An “ogee” describes a serpentine S-shape in architecture. Fittingly, the Roman Ogee bit creates a decorative S-shaped profile for molding, furniture, signs, or under any other circumstance when a beautiful S-shape is desired. Ogee bits often incorporate straight edges at the top and bottom of the pattern with a convex curve in between. Both classical and double ogee designs are available, with the latter containing two ogee patterns often separated by a squared transition. Like other edge forming bits, the tips are equipped with a pilot bearing to guide the cutting arms along the outside edge of the material. Bit diameters range from ½-inch to 2½ inch.
Best For: Making decorative S-shaped profiles in the edges of the material.
Molding bits integrate various edge-forming profiles to serve a single purpose: make molding. Molding is an incredible way to reinvent a room, and making your own moldings affords the ultimate control over your home’s finishing touches. While several other types of router bits (like the cove and roman ogee) are capable of making edge cuts for molding, molding bits save time and generate superior results. With one of these bits in your possession, the sky’s the limit: Crown molding, baseboard, and window frames can all be manufactured from a single set. There are several style options available, from classical to contemporary, to master any home remodel project.
Best For: Manufacturing molding.