The Complete Handbook of Carpentry Jointers

Chapter 1: Understanding Carpentry Jointers

The Jointer's Place in the Shop

A jointer is not a glamorous machine. It does not carve a profile, cut a joint, or shape a molding. It performs one specific, crucial task: it creates a flat, straight, true surface on the edge or face of a board. That surface then becomes the reference point for every other operation you do on that piece of wood. If your reference is false, everything that follows is compromised. A cabinet door that won't lay flat, a tabletop with a visible gap at the glue joint, a drawer that binds because its sides are twisted - these are all common failures that trace their root cause back to a poorly flattened board. Understanding how a jointer creates this true surface, and how to feed it correctly, is foundational knowledge for any woodworker who cares about accuracy.

Think of a typical task: preparing a board for a glued panel. You have two boards you want to glue edge-to-edge to make a wider panel. If you simply glue them as they come from the lumber yard, the chances are high that the glue line will look like a thin lightning bolt, with tiny gaps and proud spots. The boards might also be bowed, so when you clamp them together, the ends meet but the middle gaps. The reason is that a freshly sawn board is almost never perfectly straight or flat. It can be cupped, bowed, twisted, or have a wavy