mower blade sharpening?

[JHZR2]

Im no pro. I dont have a huge yard, it takes maybe 20-30 minutes to mow completely. I dont over fertilize, so I have a nice grass layer that doesnt grow all that fast most of the year. I bought a flathead B&S craftsman mower in 2006, new. Runs great. Though Ive changed the oil, Ive never touched the blade. I always cut the grass long, to keep weeds out and make it more self-sufficient, so its not like Im hitting roots and rocks, but I can imagine that the blade should get some attention. Can I sharpen it just using a file? How sharp should it be? How do I know when Ive done it enough? Given that I just have the OE blade, is there an "upgrade" I should look into? I dont bag the clippings. Thanks!

 

[Chris Meutsch]

I sharpen mine once a year with my Dremel. Get all the edges shiny and sharp and you're done. Takes about 10 minutes.

 

[mrsilv04]

For an "upgrade", you could get a Gator Blade. http://gatorblade.com/about.html Otherwise, you can sharpen the old one yourself with a file, or take it to a good mower/small engine shop, and they'll sharpen it for several dollars or less. Balance the blade after it is sharpened, to make sure it is still in balance from end to end.

 

[Rand]

dremel type tool or angle grinder. File would work but be very slow. Whatever you use make sure you dont overheat the blade.

 

[Kestas]

I too use a file for blade sharpening. There's no need to have the store do it. I'll use a grinder if I need to hog a lot of material off, but I'll finish with a file. It's best done using a bench vise and leather gloves.

 

[pcoxe]

I clamp the blade to a workbench and buzz down the edge with a side grinder, removing metal slowly to avoid overheating the cutting edge.

 

[JHZR2]

So the blade needs to be removed? How does one properly determine balance? Just put it on something to support it in the middle, then see how it tilts? Is a gator blade really much better?

 

[LoneRanger]

How much does that Gator blade cost? Say for a 22". I cut about 1/3 acre with a push. Takes awhile, but its decent exercise.

 

[Kestas]

The stores sell balancers for a few bucks. It's basically a cone-on-pin design. And, yes, it's easiest to sharpen and balance if you remove the blade. I use a small block of wood to safely wedge the blade against the deck when I undo the hub bolt.

 

[bepperb]

I have a Craftsman push mower, Briggs Flathead, cheapest they had in 2005. I do woodworking and I sharpened that blade to about a kitchen knife edge for kicks a few years ago. I cut the grass once and it was about as sharp as a butter knife. So don't waste a ton of time on it. After that lesson I've always just used a file and gotten it close enough. I do hear the Gator blades are an upgrade, and at the very least the metal should be harder. Also, they would probably cost less new than a store would charge to sharpen a blade. I balance on a nail in the wall, but with a file you're probably not going to remove enough material to need to balance. The carb diaphram likes to get weak as well, and I'll probably replace that 4 dollar part. That's such a common thing a hardware store stocks the part.

 

[eljefino]

Make sure you find a diagram, it is not a single knife edge but rather about a 1/8" blunt face with a 90 degree angle and a 85 ish degree one. You want the machete effect.

 

[boraticus]

I've used various methods for sharpening mower blades. For best results and keeping as close to factory blade angle, I find a bench grinder the best. However, if I don't have a bench grinder I'll use a hand held grinder with the blade held in a vise. I have a Dremmel but it's a bit small for the task. Especially for my camp mowers which get some nasty nicks.

 

[JTK]

I don't touch the blade much either. The blade on my 1999 model year Honda push mower was just changed for the first time the Summer of 2011. I never sharpened it in ~11 seasons of use and just mail-ordered a new one instead of trying to touch it up. I've tried the bench and hand grinder methods over the years, but they always look like Stevie Wonder "sharpened" them when they're done. I have yet to develop the knack. I've also taken lawn/garden tractor blades into local mower shops to be professionally sharpened. They come out great, but you can almost mail-order new generic blades for the same cost these days. Joel

 

[abycat]

I have used a good file on all of mine and have not balanced them since I dont take them off when i sharpen them. I do it once a year and they seem to cut grass just fine. If you look at the tops of the grass after mowing and they are all frayed then you need to sharpen the blade.

 

[INTJ]

Either I bought new blades or: I've used a knife/ scissor sharpener. It's a rotary disc/stone with an internal shaft. Imagine two 1/4 inch round disc shaped stones that are beveled on one side, and the bevel between the two forms a v-groove or channel. I chuck this up on a drill and sharpen them in a vise. Works quick. It was inexpensive but I don't recall where it was bought. Something that works, but was designed for something else.

 

[JHZR2]

Originally Posted By: abycat

I have used a good file on all of mine and have not balanced them since I dont take them off when i sharpen them. I do it once a year and they seem to cut grass just fine. If you look at the tops of the grass after mowing and they are all frayed then you need to sharpen the blade.

So that said, what's the benefit to balancing? What's the issue if one doesn't do it?

 

[JHZR2]

Also, when I've flipped my mower up/over, it is always harder to start, and it smokes bad for a while when I start it. Is this because the carb empties or because oil gets in somehow? How is this prevented?

 

[boraticus]

Originally Posted By: JHZR2

Also, when I've flipped my mower up/over, it is always harder to start, and it smokes bad for a while when I start it. Is this because the carb empties or because oil gets in somehow? How is this prevented?

It's from oil entering the combustion chamber possibly from the bottom of the cylinder. To avoid that problem, sharpen your blade during an oil change. Drop the oil, turn machine over, sharpen blade, refill.

 

[boraticus]

Originally Posted By: JHZR2

Originally Posted By: abycat

I have used a good file on all of mine and have not balanced them since I dont take them off when i sharpen them. I do it once a year and they seem to cut grass just fine. If you look at the tops of the grass after mowing and they are all frayed then you need to sharpen the blade.

So that said, what's the benefit to balancing? What's the issue if one doesn't do it?

If the blade is noticeably out of balance, it will have an undesirable effect on the crank bearings/bushings. It takes a fair amount of metal removal to cause enough imbalance to be harmful. Chances are you'll feel it in the operation of the machine.

 

[Kestas]

Originally Posted By: JHZR2

Also, when I've flipped my mower up/over, it is always harder to start, and it smokes bad for a while when I start it. Is this because the carb empties or because oil gets in somehow? How is this prevented?

Try flipping it to a different side or forward.