How to Change Lawn Mower Blades: A Beginner’s Guide

This information is meant for those who have never changed lawnmower blades before and who usually pay someone to do it. However, anyone can change lawn mower blades if they really want to. There is not a lot to it and basically no learning curve.

You will only need a few tools and a bit of logical thinking to be on your way to becoming a bit tech-savvy to sort out your lawn mower’s blades.

So, if you want to know everything you need to know about lawn mower blades, then keep reading, because we are going to have a look at the lawnmower and how to replace the old blade with a new one.

What You Need To Change The Blade Of the Lawnmower

You will need a new blade for your lawnmower, and make sure you get the right blade for your specific model. You can make sure by copying the whole number that is on the label on your lawnmower, including all the numbers and dashes.

You will also need the right size wrench for the nut that secures the blade to the rotor on your lawnmower. Note that this may differ between different brands. You can use a ratchet wrench with the correct size socket for this or even an adjustable wrench.

A putty knife is also necessary to clean the lawnmower after you have removed the old blade from its position.

How To Replace The Lawn Mower Blade

Remove the spark plug wire from the spark plug and tug it safely out of the way. Place a piece of plastic under the gas tank cap to prevent the gas from leaking out. Put the lawnmower on its side with the air filter pointing up.

Remove the nut that secures the blade onto the rotor with the correct-sized socket or wrench. If the nut is tight, use a block of wood and put it between the blade and the body of the lawnmower. With the piece of wood wedged between the blade and the body, you can use both hands for better leverage. Or simply spray some penetrating oil and leave it for a few minutes.

After you remove the nut, remove the old blade from the lawnmower and put it to one side for your safety. Now you can use the putty knife or a scraper to clean away all the debris that is stuck to the bottom. Before you put the new blade onto the lawnmower, make sure it is the right side up for proper cutting of the grass.

Which side is the right side up will be shown on the blade with markings or some writing on the blade. If there are no markings or any indication of which is the right side up, make sure the bladed side shows down. This means that the cutting edge of the blade should point in the direction of the wheels of the lawnmower.

Tighten the nut that secures the blade onto the rotor until you can not turn it anymore. That is if you are an average person and not too strong like some people are. The best way is to use a torque wrench and torque the nut after tightening it. You should torque the nut that holds the blade between 450 and 600 pounds for the correct torque.

Now you can put the lawnmower back on its wheels and remove the plastic from the gas tank cap. And lastly, you can replace the spark plug wire and you are ready to mow the lawn properly.

These are the instructions on how to replace a fixed blade that rotates at the bottom of the lawnmower. There are other types of blades as well, but the principle is the same on replacing the blade of a lawnmower.

Multi-blade Method

With those lawnmowers that use the multi-blade method, you need only to remove the plate from the bottom of the lawnmower. And after you remove the plate, you can remove every individual blade from the plate and replace it.

Just remember to replace the blade with the correct type of blade for your lawnmower for your safety. If you use the wrong blade, it may also cause the lawnmower to be off-balance and can hurt someone or break it.

Final Thoughts

Now you know how to change lawn mower blades quickly and easily. Lawnmower blades are not that expensive, but it is a good idea first to check if the old one can be sharpened. Just remember that a sharpened blade will not be the same weight as a new one and may also cause some problems.

The safest way is to replace the old blade with a new one that has the right weight and is properly balanced. If you are not sure of what to do, it is always best to seek professional advice. But with the above tips and guide, you should be able to change the blades on your lawn mower with ease.