Are Lawn Mower Blades Universal?

Are lawn mower blades universal? Can you replace faulty, worn, or dull blades with any that you can find on the market? It’s an important question! An ill-fitting or loose blade can be incredibly dangerous so you need to be sure that you have the right fit for your machine. A new blade can significantly improve the efficiency of your mower and the precision of the cut.

Read ahead to find out exactly what the deal is when it comes to replacing the blades in your lawn mower and what you need to know to find the best blade for you.

Are Lawn Mower Blades Universal?

There are few tools in your arsenal that will get more usage than your lawn mower. These machines work for hours every month, so it’s no wonder that the blades get worn and tired over time. Most lawnmowers work in a relatively similar way – so are the blades universal and interchangeable?

Unfortunately not. Lawn mower blades aren’t universal and you need to select exactly the right type of blade for your machine.

Everything from the thickness to the length to how they attach to the mower itself can be very specific to an individual manufacturer. The wrong blade might be impossible to install, or actively dangerous and ineffective.

That does not, however, mean that you are stuck with one mower blade forever. Many manufacturers do make multiple different types of blades for each machine so you may be able to choose an alternative that is better suited to your needs.

Whether you need a fresh blade or are just looking for a better option, you will need to identify the specific blades that are designed to fit your exact mower.

Find Your Exact Lawn Mower

The first thing that you want to do (before you start looking at new blades!) is find the make and model of the mower itself. You might know this already, but if not then you should see it clearly labeled on a badge, somewhere on the main chassis or deck of your mower.

The model number is crucial here because each individual model from any given manufacturer is likely to have very precise specifications for the blades that can be installed for it.

Looking up the make and model of your mower should help you to find the various blades that are designed to fit your machine. Using genuine parts is always the safest option even if they may be a little more pricey.

If you want to find the exact same blade again, though, how can you tell which it is?

Look At The Part Number

To make sure that you are replacing like-for-like, you can easily find out the exact type of blade that your mower already has installed by looking at the blade.

Every lawn mower blade should have a part number stamped into it. This will generally be a series of letters and/or numbers, usually found on the top of the blade, near the fitting.

You can search for this blade number directly, which will give you sellers and further information about the kind of blade you are dealing with.

Often, however, the part number can be hard to see as it may have become covered in rust or been worn away over time.

Measure The Dimensions Of The Blade

If you are unable to find out the kind of blade you are dealing with any other way, you can always resort to measuring it and finding out its exact dimensions. The three main measurements to find are the length, width, and thickness, which should help you to find blades that are the same.

Blades are generally between 6 and 32 inches in length, from 1½ to 4½ inches in width, and from 1/10 to 1/3 of an inch thick.  

These three measurements alone do not necessarily mean that a new blade will fit your machine, however. You need to also check the type and position of the central fitting as well as what sort of blade it actually is.

High-Lift Bladse, Low-Lift Blade, And Mulching Blades?

Even blades of the exact same size will not necessarily be the same in other ways. There are a variety of different blade types that you might be dealing with – and you may want to choose something different from what you have already.

Lift blades are probably the most common, and they come in two kinds: low-lift and high-lift. Low-lift blades don’t suck the grass up as much, which means they also don’t suck up the dirt below the grass. High-lift blades have much stronger suction but they can pull up loose, sandy soil as well. 

These blades look similar, as they both have a straight cutting edge, but the upward curve on the back of the blade is steeper on high-lift blades.

Mulching blades (or 3-in-1 blades) have sharp, curved edges that are designed to slice the grass into smaller pieces that are then left behind to feed the lawn. To get a good idea of all of the different kinds of blades that you might be dealing with, you can check out this detailed guide from iGo Pro Lawn Supply. 

How Often Should You Replace Your Lawn Mower Blades?

As a rule of thumb, you need to replace your lawn mower blades when they’re no longer sharp. Dull blades tend to do a bad job on the lawn, thereby exposing your grass to different problems. Even without inspecting the blades, it’s easy to know when it’s time to change them. 

Not only will it cut your grass unevenly, but it will also make the grass edges ragged. Besides, you’ll also notice that the lawn mower is making strange noises and is struggling to cut through grass.

Maintaining your lawn mower regularly will help you notice when its blade needs to be replaced. 

How to Replace Lawn Mower Blades

From time to time, you may have to replace your lawn mower blades, especially if you use the equipment regularly. Here are some simple tips on how you can do it yourself easily.

• Turn off the lawn power source and remove its spark plug or batteries.
• Place the mower on a flat surface and locate its blade under the deck.
• Using a wrench, loosen the bolts and nuts holding the blade together and remove it.
• Replace the blade with a new one and fix it properly.
• Put the bolts and nuts back in their positions and tighten them perfectly.
• Ensure the blade is stable by rotating it carefully. If it doesn’t strike other parts of the mower, it is stable. 
• Connect the mower’s spark plug or replace its batteries. 

Learn more from related post: Will a Lawn Mower Run With a Dead Battery?

Summary

So, are lawn mower blades universal? No, and far from it. Lawn mower blades are actually highly specific to the make and model of mower that you are using, and trying to install the wrong blades can be disastrous.

You should check exactly what size and specifications of blades are suitable for your machine before you start shopping around for something new.

Frequently Asked Questions