Reconditioning And Replacement: Riding Lawn Mower Blade Care
Occasionally, a riding lawn tractor or mower's blades can become unbalanced, bent, or dull, and will need either reconditioning or replacement. It is recommended that maintenance be performed on the blades at least twice a year. To care for a riding lawn mower's blades, follow the steps listed below.
Note: These materials are prepared for use by trained technicians who are experienced in the service and repair of equipment of the kind described in this publication, and are not intended for use by untrained or inexperienced individuals. Such individuals should seek the assistance of a service technician or dealer.
As with many projects, think safety first. Always wear heavy leather gloves and safety glasses/goggles for protection and always disconnect both the battery ground wire from the negative battery terminal and the spark plug wire from the spark plug. If the unit is equipped with a twin cylinder engine, remove both of the spark plug wires from the spark plugs.
2. Removing the blades
Most riding lawn mowers have removable blades. In order to reach the riding lawn mower's blades, remove the deck before performing maintenance. Do not tip the riding lawn mower on its side. This can result in serious damage to the unit. Remove the riding lawn tractor's blades by turning the blade bolt or nut counter-clockwise with a standard long-handled wrench. Do not be surprised if the blade bolt or nut is difficult to remove due to normal corrosion, dirt build-up and initial torque setting of 70 to 100 ft. lbs.
3. Sharpening the blades
Sharpen the riding lawn tractor blades by using a tool, like a hand file, which is designed to be used on hardened metal. It is not imperative that the blade be as sharp as a knife. An edge at roughly a 45 degree angle will be adequate. Most of the wear will be around the blade tip. Focus on this area. If the blade is significantly worn or gouged beyond reconditioning, replace the blade. Follow the above procedures for all the blades.
4. Balancing your blades
Before installing a new or sharpened blade, it is important that the blade is balanced. If a blade isn't balanced properly, it will rattle and vibrate. This will damage other components on the riding lawn mower. Blade balancing tools can be purchased at a local hardware store for a reasonable price. Clean all dirt and debris from the blade. If the blade is not thoroughly cleaned it will affect the balancing of the blade. There are two procedures for checking the balance of a blade that we call out in this publication. The first is when using the vertical test method, the free hanging blade will rotate on its own, heavy side downward. The horizontal test method is the second; this is when one side of the blade begins to drop towards the table top. The side that drops to the table top or rotates downward is the heavier side, and needs further sharpening or material removed to balance out the blade. After sharpening, test the blade balance again, and repeat until the blade is balanced. Follow the above procedures for the remaining blades.
5. Installing the blades
Once the blade has been sharpened and balanced, reinstall it with the proper orientation. If using an OEM blade, the word "Bottom" is stamped on the blade for the side that should face the ground. If the word "Bottom" is not present, be sure to install the blade with the raised tips toward the top of the deck. The blade bolt or nut should be tightened properly using 70 to 100 ft. lbs. of torque.