How to Change & Sharpen Your Bad Boy Lawn Mower Blades


In order to get a good cut from your Bad Boy lawn mower, you must take good care of the mower blades. Over time, blades can start to corrode, wear thin, dull and become damaged. It’s important to regularly maintain them and pay attention to signs your mower blades are going bad.

Signs like an uneven cut or a lawn with brown tips can suggest your mower blades require replacement or sharpening. A blade that has a dull edge will end up beating up your grass instead of providing it with a nice sharp cut. When this happens, your grass tips may turn brown a couple of days after you mow it.

I’ll share everything you need to know about taking care of your Bad Boy. I include how to check for a damaged blade, how to sharpen it and how to balance it. Be safe and make sure you remove the spark plug wires and ignition key to prevent your mower from starting. Take caution when accessing the bottom of your mower deck.

Change and sharpen Bad Boy lawn mower blade

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How Often Should You Change Your Bad Boy Mower Blades?

Bad Boy lawn mower blades should be changed once a year. Blades that are exposed to dirt and gravel should be changed more frequently.

Replace your Bad Boy mower blades annually when performing the routine annual service on your mower. If the blades you are replacing aren’t damaged or excessively worn, sharpen the blades and keep them on hand just in case you damage your new blades while mowing and need an extra set to finish the mowing job.

How Often Should You Sharpen Your Bad Boy Mower Blades?

Your Bad Boy mower blades should be sharpened after every 25 hours of use. For the average homeowner, you will be sharpening your mower blades twice a year. Again, when operating in sandy and gravel conditions, you will have to sharpen your blades more often in order to maintain a good cut as they will wear at a faster rate.

Do New Bad Boy Mower Blades Need to Be Sharpened?

New Bad Boy mower blades do not require sharpening before using. Mower blades are sharpened during the manufacturing process. It is later coated with a paint that covers the blade edge. This paint wears from the edge once you begin using it on your mower.

Check Your Bad Boy Blade for Excessive Wear and Damage

A dull, worn or damaged mower blade can compromise the quality of cut you receive when mowing with your Bad Boy lawn mower. If you are experiencing a bad or uneven cut with your lawn mower, it’s a good idea to check the condition of your blades. Read more about items that can affect your Bad Boy’s cut here.

A dull Bad Boy mower blade or one that has excessive wear or damage can compromise the cut quality given by the mower. If you are experiencing a bad or uneven cut with your lawn mower, it’s a good idea to check the condition of your mower blades.

Wearing on the Bad Boy Blade Sail

Check out the sail of the mower blade. The high side of the blade is known as the sail. The purpose of the sail is to assist in creating air movement under the mower deck. This air movement, along with the deck shell and baffles, create a suction to stand the grass tall while the blade passes across the grass to give it a precise cut.

The sail can wear from the dirt that moves under the deck. When the sail is no longer in good condition and has become thinner than the center of the blade, the blade must be replaced.

Chips & Gouges in Your Bad Boy Blade

Blades can get nicks in the blade edge from hitting stones and other solid objects. This can compromise the cut quality from your Bad Boy mower. Small chips can usually be smoothed out by sharpening the blade. Blades with large nicks and gouges must be replaced.

Bent Bad Boy Mower Blade

A bent mower blade will negatively affect the way your Bad Boy mower cuts. A blade can bend when you hit a solid object like a tree root or a rock. Take safety precautions before you work under your deck including removing the spark plug wires and protecting your hands. There are a couple different options for checking for a bent blade:

Check for a bent Bad Boy blade by removing it:

  • Before removing your blade, grab a hold of each end of the mower and check for any damage in the spindle housing. Rock it up and down. Disassemble your housing if you find any movement or hear a knocking noise. Replace any damage you find in the spindle housing. This could happen when you hit a hard object.
  • Remove your mower blade. Match the old blade to a new mower blade. If there is a gap between the two blades and they don’t fit together, your blade is most likely bent and needs to be replaced with a new blade.

Check for a bent Bad Boy blade without removing it:

  • With your mower parked on a level flat surface, measure one end of a blade from the ground to the blade. Record the measurement. Next, rotate the blade 180 degrees and measure the other end of the blade from the same place on the ground to the blade end. Record the measurement.

    When the different between the two measurements are greater than 1/8″, your blade is bent and should be replaced. Before you remove it, check for damage in your spindle housings for any spindle or spindle bearing damage.

Cracked Bad Boy Mower Blade

A cracked mower blade must be replaced right away. A cracked blade spinning at high speeds under your mower deck is prone to break off and fly out of the mower. This can put people, pets and structures in the area at risk of injury or damage.

Items That Can Prematurely Wear & Damage Your Bad Boy Blade

It’s good practice to walk your lawn before you mow it to remove any obstructions or items that could be damaged by your mower or could cause damage to your mower. This can be toys, sticks and rocks.

Sand and debris can cause your blades to wear prematurely, but there really isn’t much you can do about this other than grow a thicker blanket of grass to cover your lawn to reduce the amount of dirt being sucked into the mower deck.

If you choose to use lawn chemicals to help with the growth of your lawn, some may be corrosive to your mower blades and deck. I recommend regularly cleaning and removing your blades.

The corrosion can cause your blades to fuse to your deck components making them nearly impossible to remove without causing damage. Frequently removing and installing the blades will reduce the likelihood you develop this problem.

How to Remove & Install Your Bad Boy Mower Blades

Gather Tools Required to Change Bad Boy Mower Blades

  • Socket wrench
  • Work gloves
  • Safety Glasses
  • Torque Wrench
  • Block of Wood

Remove Your Bad Boy Mower Blades

  • Take safety precautions: Again, make sure your spark plug boot is disconnected and remove the key if your mower has one. Wear a good pair of gloves before working with your mower blades.
  • Access the underside of the mower deck: Gain access to the underside of your mower deck using ramps or a lift designed for your zero turn. Take caution and make sure your deck is securely in place and will not drop while working under it. Use brake and wheel chocks to prevent the mower from moving.
  • Remove the blade bolts: Lodge a block of wood between the blade and the deck housing to prevent the blades from turning when removing the bolts and washers with a socket wrench.
  • Remove your Bad Boy mower blades

Install Your Bad Boy Mower Blades

  • Clean area under your deck where your blade mounts before installing the replacement blades. If you are reusing your old blades after they have been sharpened, make sure they are balanced. Refer to the section below on a balanced blade.
  • Install blades and tighten with the bolts and washers.
  • Tighten the bolts using a torque wrench to tighten the bolts to the manufacturer’s specification as shown in your owner’s manual. Make sure you torque them correctly to avoid injury of your blade coming off the mower. Use a block of wood to help keep the blade from rotating as you tighten the bolt.

How to Sharpen Your Bad Boy Blade DIY

You can save time and money by sharpening your own mower blades. The amount of money you can save depends on the method you choose for sharpening your blade. Sometimes it’s just not worth it to do yourself. You’ll have to determine what’s best for you. Here are some tips if you choose to sharpen your own Bad Boy mower blade.

Gather the tools you will need 

  • 10″ flat metal fileOpens in a new tab., 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 

Clean Bad Boy Blade

Put on your work gloves and safety glasses. Use a rag to clean the dirt off your mower blades. A wire brush can be used for stubborn areas of buildup.

Secure Your Bad Boy Mower Blade

Securely place your Bad Boy 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 Bad Boy Blade Edge to Sharpen

Sharpen with a metal fileOpens in a new tab. 

  • 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 sharpenerOpens in a new tab.

  • 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 grinderOpens in a new tab. or bench grinderOpens in a new tab. 

  • 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 Bad Boy Mower Blade

It is necessary to balance your mower blades before reinstalling them your Bad Boy mower. Failing to do so can cause a vibration and damage to your crankshaft. A balanced blade is one that has equal weight on each side of the blade. Use a blade balancerOpens in a new tab. to check the balance of your blade.

If you don’t have a blade balancer, you can place a nail in the wall with the nail head about 3/4″ to 1″ away from the wall. Place the center of the blade on the nail. You want the blade to sit level while balancing on the nail head. If it doesn’t, shave a little more metal off the side of the blade that is hanging lower until it sits even with the other side.

When Should You Seek a Professional Sharpening Service for Your Bad Boy Blade?

You should seek a professional when you aren’t quite comfortable with your blade sharpening or balancing skills. If your blades are not correctly balanced or still worn, you could cause additional damage to your crankshaft or engine.

Personally, even though I have the tools to sharpen my own mower blades, choose to have my local lawn mower dealer sharpen my blades. They just put a nicer cleaner edge on the blade than I can achieve doing it myself.

You may choose to have a professional sharpen your blades because:

  • It is a safer option to sharpening the blade yourself 
  • Sharpening a blade is often less expensive than purchasing a 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. 

Powered Equipment Team

We're just a guy and a girl obsessed with outdoor power equipment! We are excited to share the knowledge and tips we have learned over our combined 55 years in the power equipment industry. We have both ran equipment dealerships and took pleasure in helping our customers everyday providing equipment repair, parts, purchasing, and business tips to our residential and commercial clients. We hope our blog will help you with your next purchase, repair, or project.

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