The Complete Handbook of Router Bits

Chapter 1: Understanding Router Bits

A router bit is a hardened cutting tool designed to shape, edge, hollow, or profile solid material—primarily wood, but also plastic, composite, and soft metals—by rotating at high speed (10,000 to 24,000 rpm in most table router setups) and removing stock as you feed the workpiece against it. The bit's geometry—the shape and angle of its cutting edges, the number and arrangement of flutes (the grooves that clear chips), and the size and design of its shank (the uncut portion that holds it in the collet)—determines what kind of work it can do, how cleanly it cuts, and how long it will last before wear or damage requires replacement or reconditioning.

If you have used a hand plane, a chisel, or a bench saw, you have a sense of how cutting geometry works: a sharp edge at the correct angle cuts cleanly and efficiently; a dull edge or a wrong angle tears, chatters, or stalls the tool. Router bits work the same way, but at much higher speed and with geometry optimized for rotational cutting rather than linear strokes. Understanding this principle is the foundation for everything else in this handbook—from choosing which bit to buy, to installing it safely, to diagnosing why a cut came out rough or a bit failed prematurely.

How a Router Bit Works

A router bit works through the rotation of one or more cutting edges (also called flutes or teeth, depending on bit type) that peel or chip away