Today’s topic gonna be about a question I get asked a lot about: when you have to replace blades and when you can sharpen lawnmower blade?
It’s really quite simple. You can see these blades haven’t been sharpened a whole lot because people still using them to get all you can out of them and it ain’t really nothing wrong with that as long as the rest of the blade still in good shape. But what usually happen is that your top fin, which acts like a fan to pull the blades of grass, starts thinning and chipping away. It’s still cutting alright but the problem is it starts chipping away and pieces of metal start flying out from your mower. It causes a safety hazard when they get like this.
Now the blades that you’re looking at now are off a dixie chopper and we used them from mulching the leaves and stuffs as you’re ready to be changed out in the spring anyway. As you see, they get worn out bad into the top part of the fin, like you see on this you getting eaten away from the leaves, sticks and stuffs; and they happen after time and a lot of usage.
If you take your blades off and your fins still thick here, you’re not getting too far in from grinding if your blade gets weak. Having these conditions means you’re still good to go just to sharp them and put them back. Just one normal wear and tear, but until it starts thinning out it gets paper thi where you start seeing cracks through, that’s when you want to take them off. Don’t try to weld them because you’re just making them brittle and the situation may be worse.
And when you sharpen the blades, you don’t want to get the edge to the hop. Have you seen it start turning blue? You didn’t take the temper out of that. What will happen is that it will start chipping away but that didn’t even sharp indeed. This is the first time this has been sharpened and you don’t want its razor sharp. If you do it’ll be gone in a matter of minutes or hours, depending on how sharp you got.
The other time when you need to replace blades is when they’re bent this bad. Let this set flat, in this case you can just look at that and see it’s bent bad and actually the center bolt was loose and it apparently hit the deck. Here’s another good example of a blade that should be replaced: you see it start getting too thin and chipping away on the roof in there and just starting to develop a crack all the way through.
This one had two different places where you won’t check usually. If your motor has blade adapters like this you might want to check. Take this one off and it was broken. These are just made out of cast iron. I put a new one on there to new grade five bolts and it should cut better because it gets loose in 2/3 our blade eyeline and it can flex on there too. But the seizure start pattern here and you may want to inspect the straw on the bottom of the spindle or quill assembly.
Now if you guys just keep on using this, it will not be safe because one of you do it at your own risk. I would recommend a replacement when it starts thinning out like that. It’s definitely time to get rid of it if you see cracks, just throw them out. That’s a few tips on when you should just sharpen or replace blades.
Read more: What To Do If Lawn Mower Starts Then Dies?