You don't need to sharpen you blades that often, and if you think they need sharpening, just run them up to a local hardware store or mower repair shop. They will do a correct job in sharpening the blades. I've got the same Zero Turn Commercial mower for about 7-8 yrs now, and have only had to sharpen them 4-5 times. Push mowers are pretty cheap, you might just get a new one.

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