Tip #53
Shopsmith Ovararm Pin Router
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Router Bits

Router bits come in a large variety of shapes and sizes, each designed to preform a specific operation. Generally speaking, most router bits have three main components. These are the shank, the flute and the pilot (Figure 22-2).

The shank is the part of the bit that is gripped firmly by the collet (or chuck) of the router motor. The pilot is the portion that rides against the edge of the workpiece and controls the depth-of-cut of the bit during operations. The flutes are the cutting edges of the bit.

Piloted Versus Un-Piloted Bits
When buying router bits, you have the option of selecting either piloted or un-piloted bits (Figure 22-3).

Piloted bits are used when cutting a decorative profile on a straight or curved workpiece where the entire edge of the workpiece is not to be removed. When choosing piloted bits, you can select from bits with solid pilots or bearing pilots. Solid pilot bits are less expensive, but create friction that could burn your workpiece edge during cutting. Although bearing pilot bits are slightly more expensive, they will eliminate this friction and burning of the workpiece edge.

Un-piloted bits offer no edge guide and will cut all the way to the tip. They are therefore designed for use on projects where the entire edge of the workpiece is to be removed or a decorative cut is desired somewhere within the perimeter of the stock. As a result, they should always be used with a fixture, guide pin or fence.

Router Bit Materials
Router bits are available in a variety of different materials, based upon the amount of use they are expected to receive and the types of materials they are intended to cut.

High-speed steel bits are the most commonly available type and are intended for occasional use only, or for working with soft woods such as pine or redwood. These are the least expensive of all bits and offer limited use before sharpening is required.

Carbide-tipped bits generally offer high-speed steel shanks and bearing pilots with carbide cutting flutes welded-on to provide for more extended use before sharpening is required. Carbide-tipped bits should be used for working with hardwoods such as oak or maple, plastic laminates or composite materials like particleboard. These bits are slightly more expensive than high-speed steel bits.

Solid carbide bits are usually only available in simple, straight profiles and offer the same benefits of durability as carbide-tipped bits.

Router Bit Types
Router bits are available in many different shapes for a variety of specialized jobs. Figure 22-4 shows examples of the types that are available.

Mounting Router Bits
Always insert the bit all the way into the router's collet and then back it out about 1/8" before tightening to prevent the transfer of heat and vibration from the bit to the router motor armature.

Router Bit Storage
When storing router bits, never throw them carelessly into a drawer with other tools. This could result in nicking of the edges and necessitate costly, professional sharpening. In addition, avoid storing them in a damp location, as this will cause rusting (and dulling) of the edges. One suggestion is to store them in an enclosed area with camphor tablets (which coat the bit with a thin, rust-inhibiting film).

Cleaning Router Bits
Occasionally, router bits will col-lect pitch that should be removed to prevent burning of the work-piece edges. This cleaning can be easily performed with household oven cleaner. However, always remove bearing pilots from bits to avoid getting solvents or oven cleaner in the bearings. These materials will destroy the bearing lubricant and cause premature bearing failure.

Sharpening Router Bits
As with all cutting tools, router bits require occasional sharpening for optimum performance. High-speed steel and carbide-tipped bits can be easily honed in the shop. However, if carbide-tipped or high-speed steel bits become extremely dull or nicked, they should either be replaced or taken to a professional sharpening service.

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