Introduction: How to Replace a Lawn Mower Blade

About: We are the ULTIMATE in supplying you with replacement parts from over 60 name brands, and creating award winning How To Articles and Repair Videos. is #1 when it comes to figuring out e…
Lawn mower blades must be replaced after so many hours of cutting, and the steps in this instructable explain how to perform this simple parts replacement.

Broken, dull, damaged, and mismatched mower blades can cause a number of easily-noticed symptoms.

Damaged mower blades can cause excessive vibration in the mower, while dull mower blades usually get noticed by the ugly, irregular patterns they make in the lawn.

Mower blades can be sharpened several times to extend their life and ensure that your grass gets a healthy cut, but they can only be filed so many times before a blade replacement is necessary.

If you need to replace a lawn mower blade, you can do so at

Homeowners can save themselves quite a bit of money performing simple repairs like this one. New mower blades tend to be reasonably priced, and mower blade replacements usually only require the use of a wrench.

For information about matching a replacement mower blade to your mower, please read the article, Lawn Mower Blade Measurements and Types.

Steps to Replace a Lawn Mower Blade

Mower blade mounting designs vary, but the basic steps are usually the same. Most mowers have use a very simple blade mounting design like the mower we use below as an example .

Step 1: Set the Mower on Its Side

Always set the mower on the side that does not have a carburetor so that the mower's fuel does not leak out.

Make sure the gas and oil caps are screwed on tightly before tipping the mower.

Step 2: Remove the Fasteners Holding the Mower Blade On

This just means removing one nut on our example mower, and this is usually the case for most mower models.

Use one hand to steady the blade when first loosening the nut.

Step 3: Remove the Old Mower Blade

Mower Blade Mounting Location

Step 4: Install the New Blade

Most mower designs will not allow the mower blade to be installed with the wrong side down.

Our example mower blade and its retaining plate are shaped so that the blade can only be installed in the correct position

It is possible to incorrectly install mower blades on some mowers. And it's always possible to install a blade too loosely.

Vibration and poor lawn cutting will quickly make a poor mower blade installation noticeable. A quick adjustment is all it takes to get back to work in the event of an incorrect installation.

Step 5: Conclusion

The surprising thing about this repair might be how easy it is, especially since many lawn mower owners do not take the opportunity to save money on tool repairs by doing them at home.

If your mower blade is dull, damaged, or heavily worn, visit our Lawn Mower Blades page to start your search for a compatible match and get started with this fast and easy repair.