If you want to get the mower guys fired up, ask them what is the best angle to sharpen a lawn mower blade. Believe me, this can turn into a lengthy debate. So, instead of getting caught up in a back-and-forth of numbers and statistics, I’ve put together the best information from the manufacturers. Let’s check out what is the proper angle to sharpen your lawn mower blade and why it even matters.
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What is the Best Angle to Sharpen Lawn Mower Blades To
The standard angle for a lawn mower blade is 30 degrees. However, there are also 15-degree and 45-degree blades, as well as combination blades that contain 2 or 3 different angles in a single blade.
High Lift Blade – 15 Degree
High lift blades have a twisted blade that creates more airflow, allowing it to lift the clippings into the mower deck. This design is intended for those who use a bagger, as it makes it easier to get the clippings up and into the bagging system.
Standard Lawn Mower Blade – 30 Degree
The standard blade is the go-to blade for most mowers and can be considered the best all-around blade. The 30-degree angle stays sharper for much longer than a 15-degree blade because the steeper the angle, the longer it takes to wear down. In addition, standard blades typically have a 2-3 degree twist which increases the airflow and helps to lift the clippings into the deck and is good for mulching.
45 Degree Lawn Mower Blade
Because this is an even steeper angle, it is the most durable of all the angle blades. This is great when tackling thick vegetation like undergrowth and overgrown areas. 45-degree blades are also a good choice for thicker lawns requiring robust blades to make clean cuts continuously. Because this blade angle creates little airflow, it is handy in sandy areas where you don’t want too much airflow.
Combination Lawn Mower Blade
Combination blades, also called 2-in-1 or 3-in-1, have been created to combine the best of both worlds. They mix the best features of different types of blades into one blade. For example, you can buy a combination blade with 15 and 30-degree angles. So, here you get the cutting ability of the 15-degree angle and the lift of the 30-degree angle.
How to Make Sure You Get the Right Angle When Sharpening Your Lawn Mower Blade
There are several methods for sharpening a lawn mower blade, depending on whether you can remove it or need to sharpen it without removing it from the mower. The first thing is to know what angle you’re sharpening to. The most common mistake I see is getting the angle measurement wrong. So, let’s take a look at how to read the correct angle.
Which Angle to Measure?
You want to make sure you measure the angle within the blade. So, position your lawn mower blade angle gauge over the blade, using the underside and cutting edge as reference surfaces. Your reading should be around 30 degrees with a standard blade.
Getting Different Results
You’ve taken the measurements, and the results are not what you expected. This could be because:
- You measured the wrong angle
- The blade is very dull
- You used the angle gauge wrong
- You’re measuring a non-standard blade
To get the right measurements, ensure that you are measuring the cutting angle rather than the back side of the blade. Next, verify that your gauge is reading the acute angle. Depending on the starting angle, some gauges will display different angles. You want the starting angle to be 0 degrees.
If you’re reading a used blade, then the reading will come to less than 30 degrees. This is because blades wear down during use. So, if your reading is less than expected, round up to the standard angle degree (30 degrees). Also, if you’re working with a non-standard blade, you’ll want to round to the most logical degree. For example, if your angle gauge reads 43 degrees, assume it’s a 45-degree blade.
You can also adjust the blade to the angle measurement you want. For example, you can sharpen a 45-degree blade to 40 degrees. Just make sure to stay within the 15-45 degree range, as these are the ideal angles for mower blades. Keep in mind that every time you sharpen, you remove metal, and doing this repeatedly will weaken your blade.
Checking New Lawn Mower Blades
Before you use a new mower blade, measure it with your angle gauge. This will help determine the exact angle to which you’ll want to sharpen it later. To know when you’ll need to sharpen it, head over to my article on how often lawn mower blades need to be sharpened.
How to Sharpen Lawn Mower Blades the Right Way
Knowing how to sharpen your blade to the right angle is very important. Head over to my in-depth guide on the three best methods to sharpen your lawn mower blade. You can use an angle grinder, bench grinder, or metal file. These are my three go-to methods, and I think they produce the best results when it comes to easily transferring the desired angle, avoiding uneven blade cutting edge, and creating a perfectly angled blade.
Why is the Lawn Mower Blade Angle Important?
Why is knowing the best angle to sharpen a lawn mower blade important? Well, blade angle is essential for two main reasons. First, a blade with the wrong angle will cut the grass similarly to a dull blade, which harms the grass and stresses the lawn mower. Additionally, an improperly angled blade can make it seem as if your blade spins but doesn’t cut at all, which is simply frustrating at best. Here are some of the problems that you’ll notice in your lawn if your blade angle is wrong:
- Torn Grass
- Ragged Finish
- Uneven Cut
- Increased Disease & Pest Risk
- Browning of Leaf Tips
- Adds Additional Stress to the Lawn Mower
