Stumps in your yard are not only an eyesore, but they also make it difficult to mow the grass, much less make any major landscaping improvements. You can arrange to have the stump removed, or try to excavate it yourself. However, if you just want to get the stump out of your sight and don't need to take all of it out, you can turn a walk-behind gas edger into a homemade stump grinder.
Make sure there is no power going to the motor that turns the blade. For electric edgers, this just means pulling the plug out of the socket. For gas edgers, you'll need to disconnect the wire going to the spark plug.
Hold an adjustable wrench on the driveshaft behind the edger blade and hold it fast. Try to turn the nut on the front of the blade with your hand. If it won't budge, try it with the other wrench, until you can remove it by hand. Take off the blade and any washers in front of or behind it.
Put a washer back on, and then slide a circular saw blade. This blade should be at least 1-1/2 inches smaller in diameter than your edger blade was, for safety purposes. Then add a washer and another circular saw blade, followed by a third washer.
Grasp the shaft with the wrench again and tighten the nut by hand. Then tighten it the rest of the way with the second wrench. If you drop the saw blade on the stumps you're grinding, the blades will wear away the stump quickly.