Best Grit for Sharpening Lawn Mower Blades?

If your lawn mower blades have become dull, then you will need to head to the hardware store to pick up the right grinder disc to sharpen them. But if you have ever walked down the grinder discs aisle at the hardware store, then you are aware that there is an overwhelming selection. So, how do you know which grit will give your blade that perfectly sharp edge? Before you reach for a new grinder disc, let’s take a closer look at the type of discs available and see which is the best option for sharpening your lawn mower blades.

What is the Best Grit for Sharpening Lawn Mower Blades?

When it comes to sharpening my mower’s blades, I’ve found that 60-grit grinder discs give an all-around good sharpening experience. However, going down to a lower grit can abrade too much metal too quickly compared to a higher grit disc which will struggle to remove enough and works more as a buffer.

Flap Discs or Cutting Disc to Sharpen Lawn Mower Blades

Now you know which is the best grit to sharpen your lawn mower blades, but you still need to decide which type of disc to use. Luckily in this category, there are only two options, flap discs or cutting discs to worry about.

A flap disc is designed to contour and shape metal, whereas a cutting disc is intended for cutting through metal. As a result, flap discs are a little more forgiving than a cutting disc and allow you to get a nice even sharpening. Cutting discs can achieve the same sharpened edge, but in my opinion, you need to have enough experience in order to achieve the same type of results.

So if you’re in the market for a new grinder disc to sharpen your lawn mower blades, then I recommend you try a 60-grit flap disc to achieve the proper lawn mower blade cutting angle.

Why Choosing the Right Grit is Important

Knowing which disc type and what grit level to sharpen mower blades with is going to allow you to get the best finish possible. Being tempted by other grits available could take you down the path of either destroying your mower blade or just making it nice and shiny while still having a dull edge.

Let’s take a look at the different grits available

• 36-40 – Metal Removal
• 36-60 – Edging & Chamfering
• 40-60 – Heavy Blending
• 60-80 – Deflashing & Deburring
• 80-120 – Cleaning & Finishing

When sharpening a dull blade, you need to remove enough metal and use the right amount of power to get past the dings and chips to create the sharpened edge. However, if you use too much power, it can cause you to end up grinding away the blade, rendering it useless.

In the list above, you can see that your grinder will become a tool for metal removal when using a lower grit. This is ok if you want to grind off metal like an old weld, but I would not recommend using a lower grit for sharpening.

In contrast, if you go up too far past 60-grit, you will turn your grinder into more of a sander and polisher. This option works great if you are aiming to remove scratches from metal. However, like the very low grits, the high grits are not a good fit for sharpening. This is why picking a grit in the middle is the best option when sharpening your lawn mower blades.

So, if you are sharpening your blades often and using the proper technique to sharpen your lawn mower blades, then a 60-grit grinder disc will work just fine.