Parallel universe

The standard procedure for milling lumber starts with flattening one face of a board on the jointer, then surfacing the opposite face flat and parallel to the first at the planer. You may be tempted to skip the first step and head straight to the planer. But this approach usually yields less than satisfactory results.

With both a planer and jointer, the board travels over a bed while a spinning cutterhead shaves off material. On a jointer, you guide the workpiece by hand over the cutterhead, removing material from the bottom face. A planer’s cutterhead removes material from the top face driven by pressure rollers that press the board flat to the bed. If the bottom face isn’t flat, the board simply springs back to its distorted shape after clearing the rollers. So instead of a flat face, you end up with a board that is just as twisted as when you started (only thinner).