How to Sharpen Lawn Mower Blades Without Removing Them?

lawn mower blade

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If you want a perfectly trimmed lawn, properly sharpening your mower blades is a requirement you can’t skip. Some will tell you to unmount the blade, but did you know that you can get it evenly sharpened without doing that? 

The process is tricky, so here are all the important steps involved in sharpening lawn mower blades without its removal from the machine. 

Tools and Materials You’ll Need

Admit it or not, it’s not safe to sharpen lawn mower blades without goggles and safety gloves. Some may think it’s a trivial matter, but an additional layer of protection is important when handling sharp objects like mower blades. 

green gloves and grinder

Other tools you may need at your disposal for this task are a steel wire brush and angle grinder or flat file. If you’re dealing with nicked lawnmower blades, our team urges you to use a bench grinder. This sharpening process will also require you to keep a wooden block and bucket of water on standby. 

Sharpening Lawn Mower Blades Without Removing Them From the Machine: 5 Steps

Step #1: Prepare the Lawn Mower Blades for Sharpening

There are specific precautions you must abide by when you want to sharpen the blade safely. After gathering all the materials needed, unplug the power cord from your mower deck.

You must also check if the spark plug cable is disconnected from the mower’s ignition wire. By unplugging the spark plug, you will avoid accidental starting while getting the lawnmower blades sharpened.

Before you sharpen the lawnmower blades, seal the gas tank first. Begin by removing the mower fuel tank lid and placing a plastic bag over it. After that, put back the gas tank lid and seal it tightly. Through this, you can be reassured that there won’t be any fuel spillage until you’re finished sharpening the mower blade. 

Step #2: Tilt the Mower and Cushion With a Wooden Block for Support

The crucial step to sharpening lawn mower blades without its removal is to tilt the unit sideways. From there, you can easily access the mower blade. And as long as the gas tank and carburetor are on top, it’s unlikely that you’ll encounter any problem. 

lawn mower blade

Next, set the wooden block diagonally on the far side of the mower blade. You may not know, but setting this lawn mower at a proper angle can make this task easier than usual. 

Step #3: Sharpen the Lawn Mower Blades

Once you confirm that the unit is at an appropriate angle, you may proceed to get your dull blades sharpened. As long-time lawn mower owners, we’d advise you to first clean out the grass clippings on its surface.

Using the water bucket, brush, and putty knife, ensure that the mower’s blades are free from rust and other debris. After that, set the metal file or electric grinder at the cutting edge of your mower blade. 

As you use the hand grinder or flat file, keep in mind that the mower blade must not be at an uneven angle. Besides that, the sawing motion must only go in one direction. 

Given that the lawn mower blade won’t be unmounted, there should be uniform strokes on each side. Another tip we can give you is only to sharpen the top edge of the lawnmower blade. 

sharpening a lawn mower blade

Grinding faster won’t necessarily give you sharp blades, so the best you can do is preserve that energy and do the task smoothly. 

Step #4: Lower the Mower

Having a sharpened lawn mower blade doesn’t mean you can cut grass right away. Before you do anything, our mowing experts advise you to lower the mower to check for any rough bits and edges. You should also ensure that you have a fully-charged lawn mower battery before operating. 

Step #5: Unseal Fuel Tank

Once you have finished all the ways to sharpen lawnmower blades, it’s time to remove the plastic seal from the fuel tank. After the lid is back on the tank, you’re free to take your grass blades on a test run.

Safety Tips and Reminders

Tip #1: Sharpen the Blades on an Empty Gas Tank

For economical sharpening purposes [1], we suggest honing your blades with an empty gas tank. As you’ll be titling the mower sideways, the worst-case scenario is it may spill unused fuel that you can use in the following mowing operations.  

Tip #2: Know When the Blades Need Replacement

A lawn mower blade from any brand doesn’t become needlessly dull in a snap regardless of material quality. But if you’re mowing an extensive lawn regularly, there’s a high chance that garden debris and hitting rocks lead to a dull blade. 

bad boy mower blades

And if sharpening isn’t working, maybe it’s time to inspect the blade closer. When you find your garden blades damaged beyond repair, don’t hesitate to get a replacement rather than continue to use them, which may eventually lead to uneven cuts and undesirable accidents. 

Tip #3: Nicked Blades for Sharpening

Believe it or not, a nicked lawn mower blade doesn’t always lead to replacement. As long as the shiny metal isn’t nicked beyond repair, there is nothing bench grinders can’t sharpen. 

Tip #4: Regularly Check the Blades

Your mower blades don’t have to be aggressively sharp all the time, but it helps if you check on them regularly. The mowing season is especially crucial for garden tools like these, so our team recommends sharpening sessions after about twenty hours of mowing operations to get your mower blades work well. You can save yourself from the sudden machine breakdown hassle in the long run by doing this.

Tip #5: Balance the Blades Correctly

If you don’t want weird noises coming out of your mower such as in your Cub Cadet XT1 mower model, the sharpness of your blades must be evenly balanced. You may also expect these unnecessary noises if your mower blades aren’t mounted properly in the deck.

How to Determine if Your Lawn Mower Blades Need Sharpening

If you see any indication of tearing on the blades, it’s time to get your 30 inches lawn mowing machine for a sharpening session. Other than that, screeching and noises from under the deck are other signs of dull blades. 

lawn mower blade that needs sharpening

Do Both Sides of a Lawnmower Blade Need to be Sharpened?

Tending to both sides of the blade is a huge part of sharpening blades if you don’t want to remove them. Although you only need to sharpen the blade’s top edges, you must also ensure that the other side isn’t jagged, or it will appear unbalanced during the mowing operation. 

Conclusion

Like it or not, owning a lawnmower means you have to keep the machine in tiptop shape, including the sharpness of its blade. 

We understand that it may not be an easy task for newbie mowers. However, learning how to do it yourself through this guide will surely save you time, especially if you intend to use lawnmowers to handle your regular mowing tasks.  

Robert Johnson is a woodworker who takes joy in sharing his passion for creating to the rest of the world. His brainchild, Sawinery, allowed him to do so as well as connect with other craftsmen and women. He has since built an enviable workshop for himself and an equally impressive online accomplishment: an extensive resource site serving old timers and novices alike.
Robert Johnson