John White happens to be a tool expert, but you don't need to be one to properly replace the blade on a standard thickness planer. Start by removing the cover and use the tools that come with the planer to loosen the bolts, freeing up the blade. The manufacturers' instructions will tell you their magnets help lift the blades out of position, but the magnets will actually serve you better when it's time to slip the fresh-faced blade into place. It's worth noting: Before you actually put a relatively expensive new blade in the planer, try extending the life of the old one by filing the edges with a diamond stone.
If you don't have a standard planer like the Ridgid featured here, we've got you covered too. Watch John replace the blades on Steel City's index bladed-planer. And, you can also watch John prepare to change the blade on DeWalt's planer, our tool reviewer's "best overall" choice. To learn how these planers rate compared to the other four manufacturers tested, read Tool Test: Portable Thickness Planers from Fine Homebuilding issue #202 (April/May 2009), pp.74-78.