Mower Blade Basics

Updated Feb 19, 2013

Cutting Edge

5 steps to maintain mower blades for safety, quality cutting and machine longevity.

By Larry Walton

Keep your mowers up and cutting by performing regular blade maintenance. Blades can lose sharpness, wear thin, crack or bend out of shape, which can cause safety issues, fray grass and damage mowers.

Your ongoing blade maintenance program should include cleaning, inspecting, sharpening, balancing and replacing the blades. How often you check on your blades “entirely depends on the mowing conditions,” says Craig Horstick, product support representative for John Deere. “The most typical conditions result in blade sharpening every 30 to 50 hours, or whenever it is most convenient for the landscaper to service the blades.”

In less typical conditions, such as coastal or desert regions where wind can carry debris into the turf, maintenance intervals are more frequent. “In our Phoenix and Las Vegas markets, the blades take more of a beating because of the sand,” says Howard Mees, vice president of operations and equipment for ValleyCrest Landscape companies.

Here are five steps for maintaining and extending blade life:

1.   Have a Spare. Keep extra blades available for each mower. This gives you time to tune the blades or replace them without taking the machine out of service. Consider stocking blades with different lift or mulching characteristics for varying turf requirements.

2.   Ensure Safety. Use your owner’s manuals to learn and teach proper blade removal and re-installation. Give particular attention to parking, blocking, preventing accidental engine ignition and getting the correct blades in the correct position – especially on decks with counter-rotating blades.


An angle grinder can be an effective tool for sharpening mower blades. Maintain the correct angle and check the blade for balance.


3.   Inspect Blades. Carefully examine blades for damage. Scrape off debris for a clear view. Watch for abrasion wear in shiny areas, cracks, dents and bends. A bent blade can be difficult to spot unless checked against a new blade that is measured while on the spindle. Ensure operators have a procedure for inspecting blades on site. If in doubt, they should double check with a supervisor. Remember, “If you don’t know, don’t mow.” Do not attempt to weld or straighten a damaged blade.

4.   Sharpen. Blade sharpening generally involves removing material along the topside of the cutting surface while maintaining the existing angle. In general, this can be done with a variety of tools from a file to a fully automated sharpening machine. Some landscapers use drill attachments while others use angle grinders or bench grinders to get the job done. Avoid getting the metal too hot, which can weaken the blade.

“If you don’t know, don’t mow.”

5.   Balance Blades. Wear from abrasions and uneven sharpening can throw a blade off balance. Use a blade balancer or a horizontal nail in the center hole to check a blade for weight balance. Remove more material along the cutting edge of the heavier end by using proper sharpening techniques until the blade is balanced.

“I’ve seen spindle housings cracked from out-of-balance blades,” Mees says. “The vibration causes wear on the deck.”

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