Mowing How sharp do mower blades have to be...really.

[johann]

I know it sounds basic, but how sharp do mower blades need to be? I have done them as if I was sharpening an axe. I was recently discussing with my brother, and he finishes his off with a squared leading edge, not much, mabe 1/16th of an inch flattened on the cutting edge. I know they need to be balanced but is a sharp point a waste of time?

 

[thetooth]

i sharpen mine like i would a splitting maul ( 25 degree bevel ) . sharp but not pocket knife sharp ( 15 degree bevel ) . i use a 4 inch angle grinder for the bevel and file the flat side of the blade to finish the edge .

 

[goatman 1]

Not only is a very sharp edge wasting your time, a very sharp edge will dull quickly and such an edge will injure the blade when it encounters objects.Not quite as blunt as 1/16", but a little bit. Try to duplicate the factory edge, if possible.

 

[whistlepig]

I sharpen mine razor sharp. Shave hair they will. Let the grass put the 1/16" flat on the blades if the blades do need it. The edge needs to be strong. Work the burr off both sides of the blade with a file. No different than a knife. It's something that needs to cut well. Something with a 1/16" flat on the edge won't cut as well with something with a razor edge. Try a 1/16" flat edge on a tomato.

 

[radioman]

Oh boy- this is gonna open a can of worms with various answers.

For me, If I cut regularly when its 1/3 of cutting hieght or less, I find it works better with a sharper edge, but it wears out faster. I usually would need to resharpen every 2 weeks or so. If I let the grass grow taller before cutting, say a few inches of cutting height, a blade with a slight flat edge seems to cut better and last longer. I no longer wait that long anymore, so I use the 1/3 rule and resharpen often. Lawn seems to look better that way.

 

[weedpharma]

Surely this depends on the work being done. My mowing is strictly slashing weeds and branches. Obviously razor sharp is a waste of time. If you are mowing a lawn then sharp can be justified.

Weedpharma

 

[daveshoot]

The Gearmore/King Kutter manual recommends a 1/16" flat on the leading edge, and has a line drawing of the cross section of a properly sharpened blade showing this.

http://www.gearmore.com/partsbooks/L60_L72RotMwrBook.pdf

I was just searching this yesterday. Now I need to find a way to keep lynch pins on this thing.

 

[westbrooklawn]

A very sharp edge dulls immediately when used, so it is questionable if you need to go to the bother of sharpening to a razor edge... look at the edge on a brand new blade, and you will find it isn't razor sharp. The angle of sharpening is important... generally the width of the slope should be twice the thickness of the blade. For example, if your blade is 1/8" thick, then the width of the sharpened slope should be 1/4". This is a good rule of thumb which will give you the correct angle.

 

[TripleR]

I sharpen my MMM like they come when new which is sharp, but not super sharp and my rotary cutter blades as per manual which is not sharp.

I can make it through almost a whole mowing season without having to resharpen, so you can get a good cut without knife "sharp" blades.

 

[brin]

Here is a youtube instructional video on sharpening bush hog blades....I use a 4 inch angle grinder to do mine and I leave the blades on..
YouTube - Bush Hog Blade Sharpening

 

[TripleR]

Here is a youtube instructional video on sharpening bush hog blades....I use a 4 inch angle grinder to do mine and I leave the blades on..
YouTube - Bush Hog Blade Sharpening

I would have to check my manual, but I believe on my Woods 121, it recommends a leading edge of 1/32". We also use an angle grinder on the machine, but our new DS1260 has easy to remove blades, so we may take them off.

 

[sld]

I run over so many sticks that it is hard to keep a good edge.

If I was mowing a really nice stand of bluegrass or fescue I would put a better edge on the blade. Sharper is better for the grass as it promotes less tearing and more cutting.

 

[Thomas]

Might depend on what type of grass your mowing.
For my use sharper the better because mostly clover..touch up w/hand held grinder w/pad.

 

[npaden]

I have never sharpened my rotary mower and I've been using it 4 years. My blades are more round than sharp. Seems to work fine.

 

[ccsial]

I keep mine at least as sharp as the cord on my weed eater.

 

[JCB]

I've never sharpened my rotary cutter. On my finish mowers I know that when I sharpen the blades it cuts with less engine load and seems to be cleaner.

I still don't sharpen my finish blades enough, but if you've got the time/patience/desire, I say go as sharp as you can get them.

 

[savageactor7]

Our backyard is 'fairway cut' to practice the short game so I sharpen about every 7-10 days or so.

Like a golf course I cut wet grass and that requires sharp blades. Dull blades won't cut clean and will leave a white frizzy look to the lawn.

 

[Grateful11]

1/16" flat is way too much. A 1/32" or less is better. Those of you worried
about a sharp dulling too fast, so what it will only dull to what some of you are
leaving on it to begin with. I can tell why a new blade has such a large flat on
it, it's liability they don't want you cutting yourself on an edge they put on there,
no different from all other safety features. When I bought a JD 425 years ago
fired the deck up the first time it sounded like some kind of wind tunnel. I looked
at the blades and they duller than dogs d..k, sharpened them and she was
smooth as whistle. As a Machinist I've been sharpening tools for 30 years and
I'll continue to bring mine to a sharp edge and then use a smooth file to
remove the burrs and then about 2-3 very light passes prependicular to
edge just enough to where it's not absolutely razor sharp. I use a 6"x48"
belt sander to sharpen all my blades, been doing it for years. I sharpen
about 2-3 times a season.

Those that keep them dull just remember you're adding wear and tear to your
machine, using more fuel and browning the end of your grass. Creeping Red
fescue cannot be cut with a dull blade.

 

[daveshoot]

Beats me, I am a newb... but I was just following the instructions that came with the Gearmore.

 

[Grateful11]

Beats me, I am a newb... but I was just following the instructions that came with the Gearmore.

That appears to a picture of a Bush Hog blade which personally I think 1/16" is
probably fine. You're not going to be manicuring your lawn with that.