How to Sharpen Lawn Mower Blades - Follow These Simple Steps

It doesn't take much skill to sharpen a lawn mower blade. While years of practice will make you better, anyone can learn the basic principles needed to use any of a variety of tools to get the job done. We've set up this handy lawn mower sharpening guide to use a number of different methods. Check out our introduction, then check out the tools you might have on hand to get your lawn mower blade sharpening done.

It might be natural to think that a blade spinning below 200 mph doesn't need to be very sharp to cut grass. You're right. However, a sharp lawn mower blade cut through the grass. When cleanly mowed, your grass stays green, and you can avoid the unhealthy brown or burnt look that plagues many lawns—even if they have plenty of water.

Check out the photos below to see if you can start understanding them:

In the professional landscaping world, some professionals sharpen their zero-turn mower blades every other day. When your business is beautiful lawns, you need to do everything you can to make sure they stay healthy.

As we mentioned before, you can sharpen lawn mower blades with any number of tools. One of the easiest (and fastest) methods is to use an angle grinder. Of the people I know who already know how to sharpen lawn mower blades, most use angle grinders. The reason for this is that lawn mower blades do not need to be very sharp. However, they do need a clean cutting edge - preferably at the proper angle. This clean edge allows the blade to cut through the grass at high speeds rather than shredding. Here's the difference between cutting a carrot with a knife and a 1/8-inch piece of steel wiggling wildly in the air

The first step may seem obvious, but if it's not clear, don't sharpen the blades on your lawnmower. For one thing, it doesn't give you enough room to maneuver the grinder. Second - most of the work needs to be done on the top of the blade. Third, it's dangerous because there's no good way to keep the blade from spinning on you.

To remove the mower blades, first, place the mower in a safe position. For gas mowers, remove the spark plug wires to make sure the motor doesn't ignite. Then turn the mower on its side (carburetor/air filter side up) to expose the blades. Turning it this way helps prevent engine flooding and oil leaks.

If available, use a 1/2-inch impact wrench. While just a few years ago, this might have been an obscure tool for consumers, manufacturers are bringing more and more cordless impact wrenches into the mainstream. So if you have a grinder, get one.

If you don't, use the longest ratchet and appropriate socket. If it still doesn't move, use a piece of 2×4 or similar material and hit the ratchet handle with a hammer through the wood (so you don't damage the tool). Be careful as the ratchet can easily slip off the center bolt.

Hold the blade in the vise with the sharp part of the blade facing you. Using a small angle grinder, sharpen the lawn mower blade with a smooth, steady motion along the length of the sharpened part of the steel. You want to match the existing angle of the blade, not create your own. This ensures that the blade continues to maintain its proper lift and function.

Remember, the purpose of lawn mower blade sharpening... is to sharpen the blade, not to recut a new edge from a piece of flat steel. Work with metal! Try to remove the same amount of metal from each side of the blade to keep the blade balanced.

Knowing how to sharpen lawn mower blades with a bench sander can help you in many ways. First, a bench grinder makes it easier to maintain the sharpening angle of the blade. You no longer have to rely on your hands to stabilize the grinder. Instead, a bench grinder gives you a place to place the blade and set the angle. Assuming you have followed the steps above to remove the blade from the mower.

Bench grinders reverse the process of sharpening knives. Instead of moving the grinder over the blade, you move the blade back and forth on the grinding wheel. Most bench grinders have a sloping table. With this method, you can get really consistent results. Set the angle of the table before turning on the grinder and starting grinding.

When using a benchtop sander, be sure not to over-sand the mower blades. You only have so much steel to work with before you have to get a new blade. You also don't need to do more, just re-enable the advantage. Use a fast back-and-forth pass when sharpening. This helps prevent heating of the steel and eliminates the hardening process. This helps you keep your blade sharp for a long time.

No matter how you sharpen your lawn mower blade, you want to do it by balancing the blade. When you remove metal from each side of the blade, you affect the balance of the blade. Just like your car needs all four wheels to be properly balanced, lawn mower blades must also be balanced. Otherwise, it will cause excessive vibration and reduce cutting efficiency.

Hammer a 16D or similar nail into your shed or shop stud and hang the blade from the center point. In theory, you could simply take out a nail and do it manually if needed. Due to the nature of the center hole, some blades are more difficult to balance than others. Easiest to balance using round holes.

If it stays balanced, you're done. If not, use a marker to mark the blade on the heavier side. I usually mark the edges that are actually sharpened so I can remove something.

Next, grind off more metal from that side. Be sure to keep the same cutting angle. Just do a little and recheck your blade balance.

No matter which grinder method you use, balance the blade each time you sharpen it before reinstalling it on the mower.

No matter how you choose to sharpen your lawn mower blades, be sure to wear the appropriate personal protective equipment (PPE). Protect your eyes, hands, and ears when using the grinder. Grinding lawn mower blades is very labor-saving. It's a great entry-level task that just about anyone can do.

The above describes the method of grinding lawn mower blades in detail, if you want to buy a new lawn mower blade, please contact us.

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