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what angle does everyone sharpen there blades to? the new ones I bought seem to have about a 60 degree angle but they loose that edge very rapidly. John deere blades if that matters.

60° from where?

If you check the hardness with a file and it files about like a common 6d nail you've found the answer why they dull so fast.

Oregon blade angles are 30 degrees, I have seen new JD blades at almost 50 degrees. I sharp all push mower and lawn tractor blades a about 30 degrees and rough cut mower blades about 25.

I keep whatever angle the blade comes with. The blade dulled when you hit wet grass or anything that's not normal dry grass

SeniorCitizen said:

60ｰ from where?

If you check the hardness with a file and it files about like a common 6d nail you've found the answer why they dull so fast.

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looking at the end of the blade, just guessing on the angle, however it is more than a 45

Rivets said:

Oregon blade angles are 30 degrees, I have seen new JD blades at almost 50 degrees. I sharp all push mower and lawn tractor blades a about 30 degrees and rough cut mower blades about 25.

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Thanks Rivets, I will give that a try as that's kinda what I was thinking but not sure.

Oregon has a saying called 30-30 which means sharpen the blades at a 30 degree angle and leave a .030 thick dull edge.

ILENGINE said:

Oregon has a saying called 30-30 which means sharpen the blades at a 30 degree angle and leave a .030 thick dull edge.

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There may be more behind this theory than Oregon is telling. Like if it has a .030 dull edge the odds of anyone cutting themselves and Oregon being sued is less likely.

Not me, may as well mount weed whacker string under the deck.

SeniorCitizen said:

There may be more behind this theory than Oregon is telling. Like if it has a .030 dull edge the odds of anyone cutting themselves and Oregon being sued is less likely.

Not me, may as well mount weed whacker string under the deck.

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I don't think that's why they do that.

exotion said:

I don't think that's why they do that.

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What's your theory?

SeniorCitizen said:

What's your theory?

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Well .030 is not really dull.... So it will still cut people very easily espically dumb people. I think they do that to make the blade evenly "dull" which slows down the actual process of it dulling.

The angle of 30 is very steep more like shears less like a knife this is best for the quality of cut as it generates more lift and makes a nice even cut.

I just know the right angle from years of endless sharpening. I think the key is to sharpen on a set schedule. The longer you wait, the harder it is to keep the right angle

I think you need to be clearer with the questions. Are we talking about rotary or reel mowers and how are we defining the angle in question? For example is it supposed to slope away from the forward direction of travel or towards it on the top surface of the blade? I think that defines the meaning quite well.

woolyhead said:

I think you need to be clearer with the questions. Are we talking about rotary or reel mowers and how are we defining the angle in question? For example is it supposed to slope away from the forward direction of travel or towards it on the top surface of the blade? I think that defines the meaning quite well.

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What?

How about this: Blade angle is defined as "X degrees from horizontal."

Actually it is the included angle between the top & bottom surfaces.
Two dimensions to blade sharpening.
1) the angle
2) the leading edge thickness

Now this thread is near 4 years old.

Just to clarify what everyone (?) means by the sharpening angle of the blade, could we please have some diagrams showing how it is defined? This question applies to reel mowers and to any other type.

I made a jig to check the angle 30°. I see a person can purchase a jig to attach to angle grinder and sharpen blade to same angle every time.

One can also fab up a jig. If you have the skills.

On Woods finish mower blades they specify leaving a 1/8 inch unsharpened edge. It may have been 1/16 but my recollection is 1/8. The reason for that can’t be to prevent cutting yourself.
A 1/32 flat front edge would not cut you.
If the blade is moving fast enough, almost no sharpening would work.

Knots

I remember reading .030" tip x .030" up the angle.

Most consumer blades are 34 to 37 degrees.

After everyone has sharpened their blades to that nice razors edge at the angle of your choice mow for about 10 minutes and check the edge and see how sharp it is. Rotary mowers don't cut grass as much as rip it. Sharper is better but blades round over in a matter of minutes. Ever notice new blades aren't that sharp? No reason for them to be super sharp.

Hammermechanicman said:

After everyone has sharpened their blades to that nice razors edge at the angle of your choice mow for about 10 minutes and check the edge and see how sharp it is. Rotary mowers don't cut grass as much as rip it. Sharper is better but blades round over in a matter of minutes. Ever notice new blades aren't that sharp? No reason for them to be super sharp.

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There is no doubt that freshly sharpened blades lose their edge quickly. There is also no doubt that most people do a really poor job of how often they sharpen mower blades. Most of the blades that I sharpen for customers are beat to hell and back. Wouldn’t cut hot butter. Also, the longer you leave blades on and the more stuff they hit, the harder it is to remove them. The condition of some of these blades is pitiful actually. Ripping the grass and not cutting it, resulting in poor cut quality, longer mowing times, and unhealthy for the grass.

I have literally had customers with blades so worn you couldn't tell the front from the back.

My father used to tell the story of the guy who took great care in having a beautiful lawn. One day the neighbor asked the wife if he could come into the garage & turn his blades up-side down. She laughed, agreed, and the dirty deed was done. Next time they were together, the subject turned again to how beautiful his lawn was. After they let him go on & on, they told 'em.

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