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How to Change & Sharpen Your Zero Turn Mower Blades

Owning a zero turn mower and not taking time to maintain the mower blades doesn’t make much sense. The mower blades are one of the main contributions to a good quality cut. Why make a huge investment in a zero turn to just receive a bad cut?

Change & sharpen your zero turn mower blade

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Follow all safety instructions provided in your equipment operators manual prior to diagnosing, repairing or operating. Consult a professional if you don’t have the skills, knowledge or are not in the condition to perform the repair safely.

How Often Should You Change Your Zero Turn Mower Blades? 

Zero turn lawn mower blades should be changed once a year. Inspect the blades regularly for damage and wearing that will require blades to be changed more frequently.

How Often Should You Sharpen Your Zero Turn Mower Blades? 

Zero turn lawn mower blades should be sharpened after every 25 hours of use. This is approximately twice a year for the average homeowner. Mowing in dry dusty conditions or mowing more often than the average homeowner will increase wearing on the blades and require more frequent sharpening.

Do New Zero Turn Mower Blades Need to be Sharpened?

New zero turn lawn mower blades do not need to be sharpened. New blades are sharpened during the manufacturing process. These blades will be coated with a paint that will wear off the mower blade edge once you begin using them.

Inspect Your Zero Turn Mower Blades for Damage & Wearing

Damage to your zero turn mower blades not only leaves you with a bad cut quality, but it can also cause additional damage to your deck components. Your engine may be required to work harder when operating the zero turn with worn or damaged blades.

Running worn or damaged mower blades will give you a bad and uneven cut. For more items that can affect your cut read 13 Reasons Your Zero Turn Mower is Cutting Uneven.

Zero Turn Mower Blade is Worn

Check the blade sail for wearing. The sail is the part of the blade that is higher than the rest of the blade. The function of the sail is to create air movement under the deck as the blade rotates under the mower. This air movement, in combination with the deck shell and baffles, creates a suction under the deck to lift grass and give it an even cut.

The blade tips are also subject to wearing from normal use. This is when the ends of the blade become thin and rounded. Rounded blade tips can leave a strip of grass between the blade tips leaving you with a subpar cut.

When the thickness of the sail is thinner than the center of the zero turn mower blade, the sail is worn. A blade with a worn sail or blade tips must be replaced with a new zero turn mower blade.

While you are checking the sail for wearing, also check the blade edge. A dull blade edge will not give your lawn a nice cut. Instead, it will beat up the grass and leave it torn and bruised. Finding your grass has brown tips a day or two after mowing is indication of dull blades

A dull blade can be sharpened using the steps below if the blade is in good condition.

Zero Turn Mower Blade is Chipped

Your zero turn mower blades can get chips and dings in them when they impact hard items left in the yard. Small chips can usually be removed by sharpening your mower blades. If you have large chips and gouges in your blades, you should replace them to achieve a good cut.

Zero Turn Mower Blade is Bent

A mower blade can bend when you impact a hard object. Sometimes it’s a significant bend and other times It is only a slight bend. Either way, you must replace a bent blade, not only for quality of cut, but also to prevent additional damage to your zero turn mower.

You should never attempt to straighten a bent blade even if it is only a little bend. Straightening a metal mower blade compromises the integrity of the material and weakens it.

There is a possibility of a piece of the blade breaking off. When this happens as the blade spins at high speeds, you can subject people, pets or other items to injury from flying metal.

Check for a bent zero turn mower blade by removing from the deck

Remove your blade from your mower deck and place it on top of a new blade to check for a bend in the blade. When the used blade doesn’t lay flat against the new blade and you notice a bend, you must replace the blade.

Check for a bent zero turn mower blade while installed on the deck

You can also check for a bend in your blade while it is installed on your zero turn mower. To do this, park the mower on a hard level surface.

Take a measurement from the ground to the blade tip and then rotate your blade 180 degrees and take another measurement from the ground to the blade tip. If the measurement is greater than 1/8” difference, you need to remove and replace your lawn mower blade with a new blade.

Another thing to remember is, when the impact to your blade is significant, you can damage your blade spindle and housing. You need to check this before you remove your blade. Do this by grabbing a hold of both blades and rocking the blade up and down. Wear a good pair of gloves so you don’t cut your hands on your blade edges.

Feel for movement and listen for knocking sound. If you notice either of these, you need to remove your spindle housings and check for damage. You may be able replace your zero turn spindle bearing. Some manufacturers only allow a full spindle assembly replacement.

Zero Turn Mower Blade is Cracked

Replace the zero turn blade if you find a crack. Using a blade that is cracked can be extremely dangerous. A cracked lawn mower blade has the potential to break off while mowing which can send flying metal through the air. This could injure a person or cause damage to the siding of a home. 

Items that Can Damage Your Zero Turn Mower Blade 

You can prevent some premature wear and damage on your zero turn blade by removing any items from your yard before you mow. Take time to walk through your yard and look for objects that can damage your blades and remove them.

  • Sticks, Rocks and Toys
    Solid items in your yard that are run over by your zero turn mower can damage your mower blade. A fast spinning blade impacting sticks, rocks, toys and other items can cause your blade to bend or become gouged. When you have a significant impact, you can cause vibrations through your mower from spindle housing damage.
  • Sand & Nature’s Debris 
    Sand and debris can cause your zero turn blades to become dull and worn at an increasing rate. A lawn that is sparse with grass with have a lot of sand in the yard that is pulled into the mower deck and wearing your blades.

    While you’re waiting for your grass to fill in and become thick carpet of grass, there’s not much you can do to prevent the amount of dirt from entering your deck.
  • Lawn Chemicals 
    Some homeowners choose to use chemicals on their lawn to help with lawn health and growth. Some of the chemicals used can corrode your deck components and cause your blades to fuse to your mower deck.

    Remove your mower blades periodically to ensure they don’t form a tight seal that prevents you from removing them next time.

How to Remove & Change Your Zero Turn Mower Blades 

Here are the steps to remove your zero turn blades:

Gather tools to remove blades 

  • Ratchet 
  • Work Gloves 
  • Safety Glasses 
  • Torque Wrench
  • Cordless Impact Gun (Optional) 

Remove Zero Turn Spark Plug Wires

Always remove the spark plug boots and the ignition key from your zero turn mower. You do not want the mower to start with you working under the mower deck. Set your parking brake.

Stay safe by following this safety tip along with wearing safety glasses and using work gloves to protect your hands from the sharp edges on your blades.

Remove Zero Turn Mower Blades 

Remove your mower blades using a socket and ratchets. If they don’t come off easily, you may want to use a cordless impact gun. You can also attempt to remove stubborn bolts by placing a block of wood over the head of the bolt. Hit the block with a hammer to loosen the bolt so you can turn it.

Remove the bolt, blade, and any washers your zero turn may use. Reinstall your blades and parts in the opposite order you took them off. If you are reusing the blades, make sure they are sharpened and balanced before reinstalling.

How to Safely Sharpen Your Zero Turn Lawn Mower Blades DIY 

You can save some time and money by sharpening your own zero turn mower blades. There are several different tools that can be used to sharpen your blades including a metal file, drill powered blade sharpener or a disc grinder. Follow these steps to sharpen your blades:

Gather the tools you will need 

  • 10″ flat metal file, drill powered blade sharpener, or disc grinder 
  • A vice to hold the blade in place 
  • Blade balancer or nail on the wall 
  • Rags 
  • Wire Brush 
  • Safety glasses 
  • Work gloves 

Put on safety glasses and gloves

Clean the zero turn mower blade

Use a rag to clean the dirt off your mower blades. A wire brush can be used for stubborn areas of buildup.

Secure the zero turn mower blade

Securely place your blade in a vice to keep it from shifting during sharpening. After sharpening one side, you will flip the blade and secure in the vice while you sharpen the other side.

File or grind the zero turn blade to sharpen the edge 

Sharpen with a metal file 

  • Using a file, push the file at an angle in one direction along the blade. 
  • Do not use a sawing motion when filing. 
  • Once all the rough spots and uneven edges are removed, flip the blade over, secure in the vice, and sharpen the other side. 

Sharpen with a drill powered blade sharpener

  • Power the drill with the blade sharpener attached. 
  • Place the flat guide of the sharpener along the flat portion of the blade with the cutting edge slot into the bevel. 
  • Move the sharpener up and down the length of the blade edge. 
  • Once one side is sharpened without any rough spots or nicks, flip the blade over, secure in the vice, and sharpen using the same procedure. 

Sharpen with an angle grinder or bench grinder 

  • Hold angle grinder perpendicular to the edge of the blade. Run the grinder along the length of the blade to level out any rough spots or nicks. Keep the grinder moving so it removes a little metal at a time and produces an even result. 
  • Once one side is sharpened without any rough spots or nicks, flop the blade over, secure in the vice, and sharpen using the same procedure. 

How to Balance Your Zero Turn Mower Blades

After you sharpen your zero turn mower blades, it’s necessary to balance them so you don’t damage your lawn mower. To have balanced blades means each side of your mower blade is equally weighted. When they don’t have the same weight on both sides of the blade, the blade can cause your mower to shake.

Use a blade blade balancer to check for equal weight on each side of your blade. It’s not a very expensive item and an item that can save you from a repair expense when you don’t have your blades properly balanced. You need to shave metal off the heavy side of the blade until the weight of the blade is equal on both sides.

Another option to check the balance of your zero turn blade is using a nail on the wall where the nail head sits about an inch away from the wall. Place the center hole of the blade over the nail and watch to see if the blade hangs lower on the right or left hand side of the blade.

You will want to remove more metal off the side that hangs lower until the blade sits level on the nail.

When You Should Seek a Professional Sharpening Service for Your Zero Turn Mower Blades

Even though I have the tools to sharpen my mower blades at home, I have my local lawn mower dealer sharpen mine. I keep an extra set of blades on hand so I can drop off a set to be sharpened while not being without my mower until I pick them up. It normally takes a day or two for my dealer to sharpen them.

These are a few reasons why I have my mower blades professionally sharpened:

  • It is a safer option to sharpening the blade myself.
  • Sharpening a blade is less expensive than purchasing a new blade.
  • A professional can grind down mower blades to get rid of large nicks and gouges in the steel.
  • Blade is properly balanced. This will reduce vibration and damage to your mower deck. 

Perform Annual Preventative Maintenance on Your Zero Turn Mower

Keep your mower running at its best by performing annual service on your zero turn. This includes changing the fluids and filters along with checking the mower components for wear and damage. Not only will this extend the life of your mower, you may also identify small problems that can be repaired before they turn into big problems.

Performing an annual service on your mower isn’t enough. You must regularly check the engine oil level, lubricate the mower, clean the air filter and remove debris from your mower. Check out this article for a checklist of items you need to inspect before using your zero turn.