Edger blades are high-speed vertical spinning tools that make a sharp and defined edge between foliage and concrete, asphalt or stone beds. They are thick and sharp, but the very nature of an edger blade being used means it has the possibility to come into contact with rocks, cement slabs and asphalt edges. Any of this contact will certainly dull or damage an edging blade, and if it gets battered badly enough, it must be replaced.
Remove cords and electrical power from electrical edgers, or remove the spark plug wire by pulling it off from a gasoline powered edger. Both of these actions ensure that the edger motor cannot possibly start nor can the blade be engaged.
Slide a wrench behind the blade until it connects to the inner holding nut.
Attach another wrench to the outer nut, and while holding the first wrench, turn the outer nut wrench in a counterclockwise rotation and remove the nut.
Slide the edger blade off the shaft and slide a new one on.
Twist the outer nut on by hand, then once again attach your foirst wrench to the inner nut and attach your second wrench to the outer nut. Turn the outer nut wrench clockwise while holding the inner nut wrench while doing this.
Tighten the outer nut firmly, then remove both wrenches.