How to Plane the Top of a Door

Shut the door until it sticks, or just far enough to allow a pencil between the doorstop and the door. Slide the pencil along the top of the doorjamb to transfer the line of the doorjamb to the door. If you only get a partial, angled line, that's OK.

Remove the door from the doorjamb by popping out the hinge pins with a hammer and nail set (or screwdriver) or, if necessary, unscrew the hinges from the jamb using a drill/driver. Place the door flat across two sawhorses with the penciled line up. Place clamps on both sawhorses to secure the door.

Adjust the blade on a handheld power planer to cut to a depth of 1/16-inch. Hold the planer with both hands, horizontally, parallel with the top of the door.

Pull the trigger, and ease the planer onto the top of the door, beginning where the line begins to taper and angle downward.

Push the planer horizontally along in one smooth motion when the base of the planer makes contact with the top of the door. As the planer nears the end of the door, continue adding more pressure to follow the line's slope.

Check the line. If you can still see the line, repeat Steps 4 and 5 until the top of the door is flush with the line.

Sand the top of the door by hand with 100-grit sandpaper. Round and smooth the edges. Apply sealer to the top of the door. Hang the door back on the jamb.