Edger blades can last for months or just a few weeks depending on the amount of use they receive and the type of terrain you're edging. A worn blade will be a quarter of an inch shorter on each end than a new blade. It will also have severely rounded edges. If you're still unsure whether or not you need to replace the blade, simply use the edger on a sidewalk. When you're done, look over the job. Clusters of grass from that area still attached to the sod indicate the need for a new blade. Ryobi has made blade replacement a quick and easy job.
Things You'll Need
Ryobi edger blade
Wrench included with your edger
Locking pin included with your edger
Needle nose pliers
Tip the blade end of the edger up to easily access the blade. Or lay the edger down on a work bench.
Remove the cotter pin at the end of the blade shaft by pinching the ends together using needle nose pliers, then grasping the looped end of the pin and pulling outward.
Spin the blade slowly until the holes in the inner blade adapter and the gear box align. You'll find the blade adapter on the inner side of the blade.
Insert the locking pin that came with your edger into both these holes. The locking pin is a cylindrical piece of solid steel, about 4 inches long, with a diameter of 1/8 of an inch.
Use the wrench that came with your edger to remove the blade nut, turning clockwise (the nut is on a backwards threaded shaft).
Remove the outer blade adapter then the blade.
Replace the worn blade with a new one and slip the outer blade adapter into place. Keep the locking pin in place.
Screw the nut back onto the shaft, being certain to rotate it counter-clockwise, and tighten snugly.
Thread the cotter pin back through the hole in the shaft and use the needle nose pliers to splay the ends.
If you have the Ryobi manual for your edger, read the section about replacing the blade.
Never work on the edger when the engine is hot.