You should sharpen your lawnmower blades before the first cut of the season. After that, look at your grass a day or so after you cut it. If your grass blades look ragged after you mow, then it is time to sharpen the blades. Also, if you hit a rock or something hard, you should sharpen the blades right away.
First thing, for safety, remove the spark plug wire from the spark plug. Tip the mower to the back, not side to side or to the front.
Remove the nuts holding the blades to the mower.
There are several different tools you can use to sharpen the blades. You can sharpen the blade with a metal file by placing the blade into a vice. Use a downstroke and follow the angle of the blade edge.
Or you can get a sharpening stone attachment for a cordless drill. Place the stone side of the attachment on the angled side of the blade and the plastic guide side on the flat side of the blade.
You can use a handheld grinder or a bench grinder.
Whichever method you use, remember to sharpen both sides of the blade evenly so that the blade remains balanced. To check the balance, you need a balancing cone. Set the blade on it and if it balances evenly, you are good to go. If it is not balanced, you will need to grind more off of the heavier side.
If you do not have a balancing cone, you can use a nail on a vertical surface. Hang the blade on the nail by the center hole like you are hanging a picture. The heavier side will drop if it is not balanced.
Once your blade is balanced, you will need to clean the bottom of your mower. After your mower is clean, reattach the blade with the nuts and reconnect your spark plug.
Of course, if you would like us to sharpen your blades for you, we are more than happy to do that. Give us a call at 406-652-8985 and we will get you taken care of.