WHAT IS A ROUTER BIT?
A router bit is a cutting tool used with a router to routers out (or hollow out) spaces in the surface of a generally hard workpiece. Although routers and router bits are more commonly used in woodworking applications like cabinetry and carpentry, these cutting tools can also perform in metals, plastics and various other materials. Essentially, though, these cutters are used to create joinery aids (like a dovetail joint) or to embellish work pieces with decorative or ornate effects (like formed edges, intricate inlays or surface work). With the right router bit, users can cut, trim, and shape workpieces with staggering versatility; these bits are available in numerous profiles and can be custom fabricated to create virtually any profile conceivable.
TYPES OF ROUTER BIT
Of course, there are many different types of router bit and although they all serve the same general purpose, they each do different things and achieve different results. A good router bit, though, should be sharp, should retain its sharp edge, and should be well balanced; this produces a bit that will last longer and will “chatter” or vibrate less during use. Conversely, bits of lesser quality tend to wear faster, chip easier, and chatter more aggressively. The following, then, is a basic breakdown of how router bits are most commonly categorized and their respective routing applications.
Cutter Type:
For the most part, router bits can be divided into three major types: fluted cutters, profile cutters and helical cutters. Fluted cutters are used for edging and trimming, profile cutters are used for trimming and shaping, and helical cutters, while mostly used in more easily machined (softer) materials, are designed for trimming, shaping and drilling. Of course, within these three groups, bits can be (and are) more specifically categorized – this will be reflected in greater detail below.
Construction:
Similarly, drill bits are usually fabricated with one of three compositions: solid high-speed steel (HSS), carbide tips, or solid carbide. HSS bits are the least expensive; they dull more quickly and, accordingly, are used primarily to trim laminate or for work in softer workpieces. Carbide tipped bits are the most universal bit type as they are more durable and perform (at least) reasonably well in all applications. Of course, these are more expensive than HSS bits, but they are equip to manage harder materials and they retain their sharp edges for longer periods. Solid carbide bits, as one would assume, are the most expensive and highest-performing bit type. While some might argue that their solid carbide construction is superfluous, they are durable and deliver beautiful results. Because of their cost, though, solid carbide bits are generally used by only the most practiced woodworkers.
Router bits can also be classified as edge bits, non-edge bits, or anti-kickback bits. Edge bits include a small wheel bearing which acts as a fence against each workpiece; these wheel bearings can be changed to alter the diameter of the cutting edge. Non-edge bits do not have this wheel bearing and therefore a fence (either attached to the workpiece, the router itself or to the router table) must be used with these bits. Anti-kickback bits, on another hand, feature non-cutting material surrounding the bit’s “shoulders.” This additional girth around the bit limits the material feed rate which, in turn, protects the workpiece from over-eager bit progress. This reduces the risk of kickback which occurs when a bit bites and catches the material it’s cutting. This is usually the result of material feeding too quickly. The girth of ant-kickback bits also allows the bit to stay cooler which reduces the likelihood of burnishing and allows the bit to better retain its sharpness.
Shank:
Router bits are also differentiated by the diameter of their shank or the portion of the bit that fits into the router collet. Shank sizes commonly range from about 1/2″ to about 3/8.” Although 1/2″ shank bits are typically more expensive, they are also the most popular as the thickness of their shank lends durability (in their stiffness) and also less vibration during use. Bits of a smaller shank diameter tend to be less durable and more chattery. Altogether, a 1/2″ shank bit will usually deliver the smoothest cuts and due to their greater rigidity, many larger profile bits are only available with this 1/2″ shank. Similarly, some smaller or more specialized bits are only available with a 1/4″ shank.
The shank of a router bit and a router collet must have the same diameter to be used together. Of course, collets of different diameters are available for purchase and are frequently included with the router itself. Adapters may also be purchased to help different bit shank sizes fit more comfortably.
