Reason for Dull Mower Blades?

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John Hasler
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Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: Reason for Dull Mower Blades?

Post by John Hasler » Wed Oct 25, 2017 11:10 pm

Not a hatchet grind. Grinding that .4mm back at 45 degrees will have about the same effect on airflow as leaving it flat.

spro
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Location: mid atlantic

Re: Reason for Dull Mower Blades?

Post by spro » Thu Oct 26, 2017 12:35 pm

Okay then but you understand the main point. I had to understand it. Every grind on the flat will eventually require a deeper grind on the beveled surface. It depends, of course, if new blades are on the menu. Deeper grinds of the beveled edge require attention to the heat generated and that requires quenching. Hey it is stuff you already know. Maybe I enjoy conversing with you.
If the blades aren't straight, it's only a conversation and we cut that xxxx the best we can ( do at the time) and be done with it.
We have better things to do.

John Hasler
Posts: 966
Joined: Tue Dec 06, 2016 4:05 pm
Location: Elmwood, Wisconsin

Re: Reason for Dull Mower Blades?

Post by John Hasler » Thu Oct 26, 2017 1:20 pm

Well, if you are going to maintain that flat as specified you are going to have to grind the leading edge square before sharpening. It's true that my method will use up the blade slightly faster, though.

I worry a lot more about just how to sharpen the knives on my haybine. They cost close to $300 per set (but they aren't made of chinesium like the lawnmower blades) and take an afternoon of grunting and cursing to replace to I don't want to use them up too fast. On the other hand when they are dull yield drops and fuel consumption goes up.

spro
Posts: 7058
Joined: Mon Feb 20, 2006 11:04 pm
Location: mid atlantic

Re: Reason for Dull Mower Blades?

Post by spro » Thu Oct 26, 2017 3:01 pm

Somehow I knew but mentioned anyway. Small potatoes with lawn blades compared to your experience with heavy equipment like that. Still, this minor conversation reveals some knowledge beyond a mower blade. Thanks John.

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warmstrong1955
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Joined: Thu Mar 18, 2010 2:05 pm
Location: Northern Nevada

Re: Reason for Dull Mower Blades?

Post by warmstrong1955 » Wed Nov 01, 2017 11:37 am

I've never gotten too fancy sharpening mower blades. Problem here, is a lot of sand, and too many gopher hills, not to mention some tough weeds.
Problem we had in Oregon, was a whole lot of mole hills, and a lot of grass.
Either yard, the part with real grass, is easy duty in comparison.

I stick 'em in the vise, and hit 'em with a 4-1/2" grinder, and grind 'em sharp. I pretty much maintain the original angle, but will shallow it up if I see rolling of the edges. Cheap blades tend to be softer. Only thing I measure is tip to tip length when done, and make sure they aren't too short.
Then I make sure they are balanced, and adjust with the grinder as required if need be.

Bill
Today's solutions are tomorrow's problems.

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