How To Sharpen Lawn Mower Blades

Is your lawn mower tearing of the lawn grass blades instead of cutting it? Does your lawn look like it has been eaten by a goat, in spite of being cut by the lawn mower? Wait; do not pull your hair by the root. Help is at hand. We will teach you how to sharpen the lawn mower blades at minimum price and effort.
Your Manual Lawn Mower – The Faithful Walk Behinds
Tools: The tools that your will require for doing this job are
- You and your time of about 2 hours or less
- A bastard file of about 12” long
- A small crow bar to prevent movement of rotor of lawn mower.
- A worktable will be useful for dong the job comfortably.
Procedure: You can use the following procedure as a general guide and make changes to it to suit you. Remember the procedure is not sacrosanct. The results are important, not the procedure.
1. If possible, remove the handle of lawn mower and place lawn mower on the table.
2. Secure it if possible in the clamps. If you do not have clamps, do not bother, secure it against any block, so that the movement away from you is restricted.
3. Fix the crowbar in the blades so that it will not rotate
4. With the help of the bastard file, file the edges of blades so that they look sharp. Work at an angle of 45 degrees
5. When one blade is sharpened, remove the crowbar and turn the rotor to work on another blade. Repeat the procedure until all blades are sharpened.
6. If you have a flexible shaft grinder in your DIY workshop, you will be able to complete the work within 5 to 10 minutes per blade. Make a template of blade profile before you start your work and compare frequently. This is necessary to ensure that you do not over cut at a place.
Safety Tip For You
While sharpening the blades ensure that the stroke is not too long otherwise, you may injure yourself.
Sharpening Blades Of Power Mower
Depending upon the lawn mower the procedure may vary. We have included general statements in this procedure; you would have to change the procedure slightly. Keep the maintenance manual of lawn mower handy if you have one.
Tools required.
- Siphon hose and clean container
- Heavy work gloves and goggles
- Double-cut (medium-rough) flat file
- Lumber scrap
- Socket wrench set
- Rubber mallet*
- Bench vise or C clamps
- Rotary blade sharpener accessory
- Electric drill*
- Screwdriver, or 1/4-in. rod or bolt*
- Blade balancer
- Replacement blade*
* Only if required
The list may look formidable, but tools are generally available with every DIY enthusiast.
Procedure:
The procedure is given for the simple single blade lawn mower, but the same will apply to all types of blades, whether single or double
- Wear hand gloves and clean the engine and the gasoline tank from outside
- Remove spark plug from the engine
- Remove all the fuel from the tank of the gasoline engine. Use the siphon hose so you do not spill gasoline on floor.
- Completely empty out the oil from gearbox if you have one
- Invert the engine and have access to the blade.
- Clamp the engine so it does not move and clean the blade area thoroughly
- With help of a box spanner, remove the nut holding the blade. Usually the nut will be unlocked in the reverse to direction of rotation of engine. You may engage the screwdriver in the cooling fan of engine to stop rotation of engine.
- If you find that you are using too much force to unlock the nut, put one or two drops of rust removing chemical, and try after 30 minutes
- After you remove the blade, clamp it in the bench vise and sharpen it with a file or a grinder. Sharpen only the outer 2 to 3 inches. The area to be sharpened will be known if you see the blade.
- Sharpen only to the required extent. Too much sharpening is not necessary. This is not the knife. It works at the speed of the engine
- After sharpening, check with your thumb. Be careful not to cut thumb. If you have done sharpening before, or seen some one doing it, you will know what we mean by this.
- Balance the blade with help of a small balancing tool on VEE blocks, or even on two foot rulers placed side by side
- Refit the blades, refill engine oil and gasoline and test the sharpness of blades on uncut portion of your lawn
Safety tips:
- Always use safety goggles and hand gloves when working with power tools.
- Be sure to remove the spark plug before starting. Serious accidents can happen if you do not do this.