Best way to balance a mower blade

milo2000June 3, 2009

I wanted to know how people balance their mower blades. My mower vibrates to the point of making my hands numb and a friend told me I should balance the blade. Also what is the best way to get a blade off. Mine seemed pretty tight for a ratchet. Should I try my impact wrench? Thanks.

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Impact wrench to remove, yes. Before removing the blade rotate it around the housing to check for straightness. Balancing a bent blade doesn't solve the problem.
To balance the blade, sharpen it first. Many have good luck just hanging the blade from a horizontal nail through the center blade hole and watching the heavy end drop. Remove material from the heavy end until the blade hangs level. For $5 you can buy a blade balancer which consists of a vertical nail that a cone rests on. Your blade sits on the cone as you watch the heavy end drop. Some would say the BEST way to balance a blade is to spend several hundred on a ball bearing version of the horizonal nail. You asked.

    Bookmark   June 3, 2009 at 10:36PM
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Disconnect the spark plug wire and ground it if possible. Tip the mower up so the carburetor is on the high side. Use a block of 2x4 to block the blade - sometimes you have to stand on it. This allows you to put your weight on the wrench which will usually break it loose. Remove the old blade and install a new one. When tightening, block the back of the blade with your shoe. You could fiddle around with the old blade, but I'd trash it. In the future you can balance the new blade after you sharpen it.

    Bookmark   June 4, 2009 at 9:34AM
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I assume you already know this, but to balance it you merely grind off material from the cutting edge of the heavier end until the blade balances out correctly. To ensure the blade isn't bent just measure from the blade tip to the ground, then turn the blade 180º and remeasure the other tip, the measurements should be the same.

    Bookmark   June 5, 2009 at 11:13AM
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I have had the experience involving blade balancing in which the vibration increased after balancing. The mower is a John Deere JS 36C.
The problem probably began when mower blade hit a tent stake buried in the grass and sheared the flywheel key.
Everything worked after I replaced the key but the whole mower vibrated much like the one described.
Balancing the blade merely made the vibration worse.
I am going to replace the blade before the grass grows enough to mow.

    Bookmark   January 29, 2015 at 3:59PM
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You have a bent crank. No amount of balancing, nor a new blade is going to resolve the problem. Your engine is toast.

    Bookmark   January 30, 2015 at 6:31PM
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Attached a link to a "typical" blade balancer, you'll see them made from plastic, metal, etc.

FWIW, DO NOT "assume" a new blade is balanced. When I ordered mulching blades for my GT-5000, for whatever reason, checked them prior to installation. Two were perfect, one had to have quite a bit ground off to balance it.

Prior to balancing, sharpen, then scrape off any dried grass everywhere, as it does make a difference, then put on balancer.

Good luck,


Here is a link that might be useful: Typical Blade Balancer

    Bookmark   January 30, 2015 at 9:33PM
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"â¢Posted by ggoyeneche New Jersey (My Page) on Fri, Jan 30, 15 at 18:31

You have a bent crank. No amount of balancing, nor a new blade is going to resolve the problem. Your engine is toast."

The OP never stated he hit anything so by diagnosing a bent crank and changing the engine is a bit premature in my opinion. I'm not saying a bent crank can be ruled out, it's quite possible it is a bent crank. More details would be helpful such as when it first manifested itself and under what circumstances.

    Bookmark   January 31, 2015 at 12:31PM
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I was referring to the post immediate above mine where "encee1424" said that he hit a tent stake. I could care less what happened SIX YEARS AGO by the original poster.

Read the train of posts more carefully before your pop off.

    Bookmark   January 31, 2015 at 1:22PM
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Please accept my apologies, indeed I should have read the posts more carefully, you were not replying to the original poster.

However you may have chosen a better selection of words by reminding me.

This post was edited by itzbinnice on Sun, Feb 1, 15 at 7:40

    Bookmark   January 31, 2015 at 3:42PM
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