Do I Need to Balance a Lawn Mower Blade? (Solved & Explained!)

To reduce stress on your mower and ensure your lawn is cut is efficiently and evenly, you will need to keep your lawn mower blade balanced. Blades become unbalanced when they are sharpened incorrectly, or if grass becomes encrusted onto them.

In this article we will cover why you need a balanced blade, how to actually balance it, and what equipment you’ll need to do it. Let’s mow!

Why do I need to balance a lawn mower blade?

Mower blades can spin in excess of 4000 rpm, which is 4000 reasons to keep your fingers well clear of them. According to the laws of physics, something moving that fast in an unbalanced way is likely to cause problems.

This usually means the blade shaft, spindle and even the motor can become damaged over time, which will reduce the lifespan of your mower. Bummer.

How do I know my blade is unbalanced?

Just by looking at the blade, it can be hard to tell if it is unbalanced. Instead, you’ll likely notice that even after sharpening, your grass is cut unevenly.

On top of that, you will notice the mower vibrates significantly when in use. This is caused by the quickly and unevenly rotating blade jarring the entire mower.

How does a mower blade become unbalanced?

A mower blade can become unbalanced in a few ways, some of which are easier to deal with than others. A build-up of encrusted plant matter on one side of the blade can be enough to put it off balance, so it always pays to keep it clean. Use a metal scraper if necessary to remove stubborn debris.

Usually, the problem will persist after cleaning. In that case, it’s likely because there’s more metal on one side of the blade than the other. This usually happens after you sharpen the blade, as the sharpening process removes material.

What equipment do I need to balance a lawn mower blade?

To balance a mower blade, you will need the same equipment you would need to sharpen it, as the procedure is essentially the same.

You will need:

  1. Safety goggles or glasses to protect your eyes from flying sparks.
  2. Thick leather gloves to protect your hands.
  3. A wrench or ratchet and socket to remove the blade and reinstall it
  4. A file, grindstone, or angle grinder to balance the blade.
  5. A nail and a piece of wood for checking the balance.

How much does it cost to balance a lawn mower blade?

The short answer is balancing a mower blade costs nothing except your valuable time. However, if you need to purchase some tools or safety equipment, it might cost you a few bucks, though it probably won’t bankrupt you. Probably.

The most expensive item you might have to purchase is an angle grinder, which usually start at around $50 to $100 for low end models.

How do I make a lawn mower blade balancer?

To make a balancing tool, hammer a nail into a sturdy piece of wood, and simply clamp or weigh down the other end on the side of a desk or bench.

Place the hole at the center of the mower blade into the nail, and the blade will naturally tilt to the heavier side if it is unbalanced.

How do I balance a lawn mower blade?

Now that you have the tools you need for the job, we will quickly run through how you can get that blade perfectly balanced, as all things should be.

  1. Remove the spark plug. This prevents the motor from accidentally starting while your fingers are in the firing line.
  2. Turn the motor on its side. This allows you to remove the blade without the danger of oil leaking into the air filter.
  3. Remove the blade. Use a wrench to loosen the bolt attached to the blade shaft.
  4. Clean the blade of any debris using a cloth and denatured alcohol, or a scraper and penetrating oil for tough dried-in dirt.
  5. Mark the blade with a permanent marker or a spray can. This lets you know which way the blade should be put back into the mower. If the blade is put back in upside down, it will not cut properly when used.
  6. Use the balancing tool you made earlier to check which side you need to grind.
  7. Use an angle grinder, file, or other sharpening tool to remove material from the heavier side of the blade.
  8. Check the balance again to ensure it is even and not tilting to one side.
  9. Return the blade to the mower, using the mark you made in step 3 to reinstall it correctly.

How do I check that my blade is balanced?

As recommended by RCPW, if you want to check the balance more precisely, you could use a magnetic blade balancer. They work in a similar way to the DIY balancing tool we described earlier but are more accurate and easier to use.

The true test, however, comes once you fire that mower up and take it for a ride. If your blade has been balanced well, you should experience reduced vibrations when mowing. The grass length after cutting should be uniform, and there should be less grass ripped or pulled from your lawn, giving a smoother result.

How can I prevent my lawn mower blade from become unbalanced?

Now that you’ve done so much hard work to make sure your blade is a perfectly balanced, grass murdering machine, naturally you’ll want to stop it becoming unbalanced in the future.

Since you have your own DIY balancing tool, you can confirm that the blade is balanced before reinstalling it after each sharpening session.

Before you mow, you should clear rocks, sticks and other large debris from your lawn as these can cause the blade to become dented and cracked which can affect the balance.

Finally, always clean your blade of grass or dirt that has become stuck to it, as this can cause balance issues.