The Best Method For Balancing Lawn Mower Blades After Sharpening

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So you've got the perfect mower for your grass type, but you notice your lawn looked ragged and torn after you finish mowing. Recognizing this as a sign it's time to sharpen your mower blades, you dutifully remove the blade from the deck and freshen up the edge. However, regardless of which of the different ways to sharpen mower blades you use, the job isn't actually complete just by honing the edge alone. In order for your mower to cut properly, the blade doesn't just need to be adequately sharpened, it also has to be balanced. There are several ways to balance a mower blade using makeshift tools you can most likely find in your garage or shed. However, the absolute best method for balancing lawn mower blades after sharpening is to use a blade balancer.

At this point, you may be wondering why you need to balance a mower blade since the sharp edge is what does the cutting. But uneven cutting is not just a sign of dull blades — it can also indicate they are off-balance. Ditto for excessive vibration while you're mowing, which is a result of an unbalanced blade wobbling as it rotates. Not only can an unbalanced blade affect your mower's performance, it can shorten its lifespan by causing excessive strain on the shaft, leading eventually to mechanical failure.

In order to know how to balance your mower blades, you must understand how they become unbalanced and the role sharpening plays in that process. Sharpening your blade actually removes metal. All those metal shavings equate to weight. Unless the same amount of material is removed from each side of the blade, it will be unbalanced to some degree. The problem is, it's almost impossible to tell how much has been removed with any accuracy just by looking at the blade. This is where a balancer comes in. 

Blade balancers — like the Oregon Precision Blade Balancer — are essentially conical devices designed to fit inside the center hole of the mower blade. To check the balance, place the balancer on a solid surface, then set the blade on top of it with the tip of the device protruding through the blade's center hole. Wait a few seconds for the blade to stop moving. If it's sitting level, it is balanced and ready for the mower. If it tilts one way or the other, it is out of balance and needs a bit more work.

To correct an unbalanced blade, you need to remove more metal from the heavier side by sharpening the blade a bit more. The steeper the angle the blade is sitting, the more material will need to be removed from the lower (heavier) half of the blade. However, you need to be careful not to overdo it, causing the blade to be unbalanced in the other direction. In order to avoid this, place it back on the balancer to check progress after every few strokes with a file or grinder. Never grind the back or outside edge of a blade, only the cutting edge.