There are two keys to a smooth-running jointer: tables that are perfectly parallel and sharp knives that are set to the identical height. A jointer with sagging tables won’t cut correctly no matter how sharp the knives are. Likewise, perfectly aligned tables won’t make dull knives work better. You need to check and fix both, or your jointer will never flatten or square anything properly. Jointer whiz Roland Johnson shows how to do both jobs with tools you already own. He also offers some tips for upgrading if you want to take your jointer to the next level.

From Fine Woodworking #230