Sharpening Mower Blade

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llO0DQLE
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Sharpening Mower Blade

Post by llO0DQLE » May 20th, 2017, 10:40 pm

I'm trying to sharpen my mower blade for the first time with the grinding stone that attaches to a drill. First thing I noticed was that the angle of the stone didn't match the bevel of the blade. I said what the heck and proceeded to reprofile the blade. I hope I didn't mess anything up. How far am I supposed to go with sharpening the blade? I've seen some pics and videos where only the last 3 - 4 inches of the end of the blade is sharpened. Wouldn't this leave uncut grass in the middle of your mowing path?

For reference, the middle of the blade where the hole is for the bolt to attach it to the mower is right next to the clamp in the pic just to the left of it.

ImageImage

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MorpheusPA
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Re: Sharpening Mower Blade

Post by MorpheusPA » May 21st, 2017, 9:32 am

I don't know jack about reprofiling, so I'll leave that to an expert.

The outer three to four inches is what cuts the grass; the inner part of the blade never really cuts anything, but does help to mulch up what's whirling around in there a little bit. As you move, the outer edge does all the cutting, by the time you pass with that, it's cut.

In my mower's case (which is a bit odd for other reasons...), the blade actually angles downward as you move from the center to the edge. Only the outer inch or so does any cutting, although there are three cutting blades across the deck.

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llO0DQLE
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Re: Sharpening Mower Blade

Post by llO0DQLE » May 21st, 2017, 7:36 pm

lol thanks Morph, I just totally forgot that with the blade spinning it cuts the grass at the front and back (not just the sides) and as you push the mower it catches the center section that would be left standing if you were standing still.

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llO0DQLE
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Re: Sharpening Mower Blade

Post by llO0DQLE » May 21st, 2017, 7:39 pm

Since I already reprofiled the one side, I did the same to the other to make them the same. The upper/inner curve (which I think is the mulching part) - I sharpened with a file by hand. I guess we'll see how it goes. Unless someone can tell me if by changing the profile of the blade, I'm risking wrecking my mower... (Andy's reply in the other thread made me think that maybe it would be detrimental)

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ken-n-nancy
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Re: Sharpening Mower Blade

Post by ken-n-nancy » May 23rd, 2017, 9:39 am

llO0DQLE wrote:
May 21st, 2017, 7:39 pm
Unless someone can tell me if by changing the profile of the blade, I'm risking wrecking my mower... (Andy's reply in the other thread made me think that maybe it would be detrimental)
Most important thing for the mower will be that the blade is still balanced. When removing lots of material, it's easy to botch this up.

To check the balance of the blade, stick a screwdriver in the hole in the center of the blade, and hold the screwdriver pointing straight ahead like a divining rod, with the mower blade oriented like an airplane propeller, horizontally with one end pointing to the right and the other end pointing to the left. Hold the blade motionless and let go gently. If either end starts to drop to the ground, that end is too heavy and needs more material removed. Remove more material from the heavy end by sharpening it some more. Repeat until the blade is balanced.


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llO0DQLE
Posts: 1420
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Lawn Size: 1000-3000
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Re: Sharpening Mower Blade

Post by llO0DQLE » May 24th, 2017, 1:44 am

Thanks KNN. The sharpening stone came with a balancing tool and I was able to balance it. It cut fine as well. Seems like it's gonna be fine.

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