Do you bother to sharpen your lawn mower blade? Why?

[Jon Danniken]

Yes, of course. I'd like to do it every year, but I tend to only get around to it every other year. Same as with the oil (I do top it off a few times every year, though, if it's low).

Jon

[Chief Two Eagles]

Not likely you would notice unless it was grossly imbalanced. Most of the time you are just going to cause the bottom crank bearing to wear a bit quicker if the imbalance is slight. I pull the deck off my Deere LT155 twice a year and lube the shaft bearings, power wash the underneath, and grind the blades on a jig I made my self. I have a little cone shaped thing to check the balance which is usually close enough for me. This is a 10 year old tractor with only the deck belt needing replaced so far.

[Bob Villa]

And the magnito or ignition.

[Ed Pawlowski]

Interesting. The left side says to keep the blade sharp, the right side says they don't recommend sharpening. Maybe they mean DIY versus a pro doing the sharpening.

Sharp blades do cut better while the dull ones chop and tear the grass apart. I happen to have a belt sander and it does a good job quickly.. A grinding wheel is a bit harder to handle, a file works too. It does not have to be perfect like a butcher knife, but it all helps. Take the same number of passes on both sides to help keep it balanced.

[Chief Two Eagles]

The flywheel contains a magnet that passes by a coil and induces a voltage in the primary of the coil. Timing is crucial here and why a motor wont start if the shear key has done its job after a blade collision.

[Steve B]

I, personally, do not sharpen my blades. Never have. But if I were to do it, I have about six tools that would do it without me having to remove the blade.

Steve

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[RonB]

I can't imagine paying someone to sharpen a blade. I sharpen our push mower and the double blades on our garden tractor /mower and it doesn't take that long. I do the serious sharpening with my bench grinder, then dress them with a hand file. It probably takes more time to dismount and remount the blades than to sharpen them.

By the way, if you are hitting rocks, stumps or such you might want to clean up the yard a bit. One good "thunk" will bend the crankshaft, and/or take out the lower bearing on most push mowers. Then you don't have to worry about the blade :^)

RonB

[jamesgangnc]

I've watched people balance them but I just don't see any reason to. I think they would have to be grossly out of balance to matter. I don't try to grind out any really huge nicks. If 90% of the blade has a sharp edge I quit. After about a 1/4 of the blade is gone I buy another one. My old lawnboy got retired to our lake house about 8 years ago where it's now 18 years old. Never balanced a blade on it in that whole time. I'va had to put a few parts on it but never any motor internals. May matter more if you are a pro running your equipment 6 - 8 hours a day.

[tom]

I sharpen my own blade about once a season. A sharp mulching blade on my Snapper cuts much cleaner, accurately and mulches much more effectively than a dull one. It take me about 5 minutes remove blade, 5 to put in vice and sharpen with a file and another 5 to replace. Have done this for at least the last 25 years.

[beecrofter]

Here in CT usa a plain rotary mower blade is resharpened and balanced for $6.25 and a mulching blade for 7.5

It might be a dollar extra for the fools who mulch countless rocks and stumps:)

[James H.]

This morning I called the Briggs and Stratton recommended lawnmower shop for my zip code (95134).

They told me it will always costs me $45/half hour shop rate for anything they do.

Therefore, they recommended I try to have other work done because a half hour is their minimum charge.

[Stormin Mormon]

A little vibbbrrratttiiioonnn nevvvveer hurt annnyonnneee????

[Ed Pawlowski]

I can see where it can take a half hour to remove a blade that has not been off for years. If it is a quickie, get the oil changed at the same time to get your $45 worth.

[Tony]

Yes that is true, I learned that in shop class back around 1970. Engines with no direct mounted blade normally have a cast iron flywheel, or some kind of flywheel with some weight to it. However, if the motor is worn and doesn't have a lot of compresion, it will run with the blade removed. And it'll scream like a 2 stroke! Did that as a kid with a little 3 wheeled riding mower that was about shot. Wasn't worried if the engine blew.

[Tony]

Of course. If it didn't work better when sharp, they would sell new ones dull.

They are probably listening to one of their lawyers that see danger in the home owner sharpening their own blades.

[Oren]

While you have the flywheel off, clean any surface rust from the magnets and on the ignition. A fine sandpaper will work.

Once had a magnet fall out of the flywheel. Forget what I used to secure it with. (Glue?)

-- cut the grass too the roots and go fishing

[Oren]

Roger that!

5 minutes with a file I can even get the nicks out.

[J Burns]

My walk-behind mower cuts more quietly with a sharp blade because the governor calls for less throttle. It means fewer gas stops and a cooler engine. A sharp blade produces less of the sticky pulp that tends to build up and clog a mower.

If you pay somebody to sharpen it, you also have to take the blade to him.

Once I have a suitable wrench in my hand, removing the blade of a walk-behind mower is very quick. I sharpen with a side grinder. I take care not to overheat the edge, but I'm not sure if overheating will leave the edge softer. I finish up with a big ceramic hone. After installing a blade, I measure the height of a blade tip, rotate 180 degrees, and make sure the other tip is at the same height. Uneven heights would mean vibration.

[willshak]

He doesn't advise against removing the blade. He says 'HE" doesn't remove it.

Again, he is showing an alternative to sharpening without removing the blade. He doesn't say NOT to remove it. Do you have one of those grinders?

[James H.]

Good point.

Yes. I have a Dewalt grinder just like that, only my stone is new (his was old and maybe old is better).

I also have dremel tools and files but for now, I think we have our answer on the sharpening:

a) Some people never sharpen; others do about yearly. b) It won't make much different; but it might make some difference. c) Almost everyone removes the blade to sharpen & balance; some don't. d) Easiest balancing method I've seen is that which the Craftsman manuals says to do which is to hang the blad on a nail horizontally. e) A new blade (for my mower) is $14.50 + 10% tax + shipping to CA; while the nearest Briggs & Stratton shop won't charge less than $45 to sharpen (I didn't ask about tax) and I have to bring the lawnmower and/or blade to them.