Router Bits

photo of router bitsConfused by which router bits to buy in order to make the best use of your router? If you don’t use a router routinely, the options can be seem overwhelming at times. The best way to get a grasp on this is to break the task down into categories or tasks considering the variables involved. Let’s start with three basic questions:

  1. What size router are you buying bits?
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  3. Are you going to be performing the routing task using a router table or hand-held?
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  5. What is the specific woodworking task being performed (routing a profile, joinery, removing material, etc.)

Match shank size to router size

The router bit shank is the solid, cylindrical part of a router bit. It’s the part of the bit that goes into the collet of the router. Compact routers (Trim routers) and converted rotary tools use 1/4′ ‘ or 1/8’ ‘ bits. Full-sized routers use 1/4’ ‘, 1/2’ ‘ and 8mm bits. The later associated with European routers like Festool. Most large routers default to 1/2’ ‘ shank bits because because large profiles need the extra shaft diameter for support and the larger shaft reduces vibration. They typically produce a smoother cut and have longer cutter life. Normally a collet adapter comes with a large router permitting the use of 1/4’ ‘ bits. That said, full-size routers which only accept 1/4’ ‘ bits are still available and in wide use. Except for very small and very large profiles, router bits typically are available in all shank diameters.

Match the bit with the router technique
Router bits dedicated to specific tasks like making multi-profile mouldings (with a single bit), stile-and-rail routing used in cabinet door construction and making raised-panels are large and can only be used safely in a table-mounted router. In addition, they generally require a variable speed router. If the routing operation is to be performed using a router table you have a full menu of bits available. If routing by hand, be safe: stick to the smaller, common profiles that can be safely accomplished using this technique.

Match bit to task

Router bits come in many profiles (the term for the shape of the cutting edge). Here are some of the most common ones used.

  • Straight Bits
    Straight router bits are a workshop staple, these bits make cuts straight into a material to form a groove or dado (a groove across the wood grain) or to hollow out an area for a mortise or inlay. They come in a variety of diameters and lengths.
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  • Rabbeting Bits
    Rabbeting router bits are guided by a spinning pilot bearing at the tip, these bits are designed specifically to cut a rabbet (shoulder) in the edge of a workpiece often used to join pieces. They can be purchased in a set that includes bearings of different diameters, allowing a single bit to produce rabbets of different sizes.
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  • Flush-Trim Bits
    Flush trim rouer bits as the name suggests, these bits are used to trim the edge of one material flush with the edge of another– for example, trimming a veneered surface flush with a substrate or using a pattern to create multiple identical pieces. They usually are guided by a pilot bearing that’s the same diameter as the cutter. The bearing may be at the tip of the bit or at the base.
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  • Chamfer Bits
    Chamfer router bits cut a bevel of a particular angle to ease or decorate the edges of a surface. They also can create the beveled edges needed to join multi-sided constructions. Chamfer bits can be used to produce multi-sided boxes, planters, waste-baskets, and other decorative pieces.
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  • Edge Forming Bits
    Edge forming router bits are most often used to cut decorative edges. For example, Round-Over bits cut a rounded edge of a particular radius (such as 1/8″ or 1/4″); Ogee bits cut variations of an S-shaped profile; Edge-beading bits cut a quarter- or half-circle profile (called a bead); Cove bits cut a concave quarter-circle. Many edge-forming bits include a pilot bearing. In most cases, these bits are used for final decoration of a project where edges have already been established and can serve as guides.
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  • Specialized Bits
    Specialized router bits are dedicated to specific tasks. Examples are molding bits, stile-and-rail bits, raised-panel bits, dovetail bits, drawer-lock bits, finger-joint bits and lock-miter bits.