Manual Lawnmower Blade Sharpening

Sharpening your lawnmower blades can extend their life as well as save you money. For the time it may take you to drive to purchase a lawnmower blade, you can sharpen your own and leave the money in your pocket. In commercial mowing, sharpening can extend blade life one to two days, which is substantial considering the number of blades a contractor may go through in only a week. For the average homeowner, sharpening can extend blade life weeks or even months. The following are steps for manually sharpening lawnmower blades.

Things You'll Need

• Mill file
• Bench grinder
• Safety glasses

Instructions

How to Manually Sharpen Lawnmower Blades

1. Remove the blades from the lawnmower and prepare either a large flat file, or mill file, or a bench grinder. If there are nicks in the blade or if the cutting edge is noticeably rounded, use the bench grinder.

2. Hold the cutting edge of the mower blade away from you and at an upward angle in contact with the grinding wheel. Move the blade continuously from side to side so as not to build up too much heat.

3. Use the mill file if there are no nicks in the blade. Secure the blade with the cutting edge pointing up. Move the file against the blade in a direction away from your body following the upward direction of the cutting edge. Make each filing motion in the same direction.

4. The blade is adequately sharp just before it has a fine edge, with the very edge of the cutting surface being narrow but noticeably flat. A fine edge will result in the blade being easily nicked.

5. Discard the blade if there are elongated gashes or cracks in the cutting area of the blade. Cracks, gashes and the cutting surface being too thin to sharpen are signs to get new blades.

Tips & Warnings

• Blades will weaken if allowed to become too hot.

• Sharpening till the blade is too thin will greatly shorten its life.

• Moving the file back and forth across the blade can result in an uneven cutting surface.

• Wear safety glasses and long sleeves when using a bench grinder. Bench grinders produce many sparks and larger metal projectiles.

• Don’t turn mowers on any side when removing a blade. This can result in a mower not starting.

• Always remove the key from a riding mower before moving near the blades.

• Never move near mower blades or turn a mower on its side while it is running.

• Moving the file toward a sharp blade edge can result in injury.

• Be cautious when wearing gloves or loose clothing during the use of a bench grinder as they can be caught in the grinding wheel.