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  #1  
Old 10-06-2012, 09:58 AM
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MOturkey MOturkey is offline
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Another Question Concerning Blade Sharpening

Okay, I know this topic gets worn out on here, but I'm interested in getting some more information on something. I have a Magna-Matic sharpener and try to replicate as closely as possible the factory edge on the OE blades I use. In other words, I sharpen the blade to somewhat less than razor sharp.

I think most of us are aware that if you overheat a blade during the grinding process to the point of discoloring the metal, you have removed the temper, and the blade won't hold an edge as long. I also realize quenching the blade in cool water can help reduce the likelihood of this happening. My question is, for those knowledgable on the subject, is there any benefit from quenching even if you don't have a problem with heating the edge to the point of discoloration? In other words, does the heat produced from grinding soften the metal over time even at lower temperatures?

It seems to me that as my blades get more worn, they don't hold an edge as well, and get more nicks and dings than newer blades. This observation isn't scientific. I've never tried to keep track of the hours etc, not sure if it would be possible anyway due to the wide range of conditions the blades encounter on a daily basis, but it just seems to me like my blades that are close to the end of their useful life tend to need changing out more often than blades I've just put into service. Thanks for any input.
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Old 10-06-2012, 10:52 AM
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PlantscapeSolutions PlantscapeSolutions is offline
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I find if you care about quality and want to minimize the amount of grinding you do then daily sharpening is a must. The Magna-Matic is not a machine for sharpening blades that are allowed to become really dull.
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Old 10-06-2012, 01:53 PM
williams lcm williams lcm is offline
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I personally sharpend my blades to razor sharp. I have not noticed them dulling any faster. Yes they sometimes turn blue while sharpening but I sharpen daily and have never had a problem.
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Old 10-06-2012, 09:04 PM
orangemower orangemower is offline
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Quote:
Originally Posted by williams lcm View Post
I personally sharpen my blades to razor sharp. I have not noticed them dulling any faster. Yes they sometimes turn blue while sharpening but I sharpen daily and have never had a problem.
You can make claims like this all day long but others that know better will think you're dumb. I can't see how blades would need sharpened daily if they're sharpened correctly.
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  #5  
Old 10-06-2012, 09:27 PM
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Florida Gardener Florida Gardener is offline
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Originally Posted by orangemower View Post
You can make claims like this all day long but others that know better will think you're dumb. I can't see how blades would need sharpened daily if they're sharpened correctly.
If you cut a lot of properties per day, you prob need to sharpen daily.
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Old 10-06-2012, 02:24 PM
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THIESSENS TLC THIESSENS TLC is offline
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if your quenching the blades in cool water, you are hardening (annealing) the blades and causing them to become very brittle which will increase the nicks you are getting. If you dip them in oil instead of water, you are still hardening them but not as quick as water. water shocks it almost instantly, which makes it very brittle. water will make it extremely hard but can also cause it snap, crumble etc. if hit hard. oil will still harden the blades but at a slower rate, and will not be as brittle. hope that helps...probly not the answer your looking for, but thats what i know.
happy thanksgiving!
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Old 10-07-2012, 10:07 AM
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MOturkey MOturkey is offline
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Quote:
Originally Posted by THIESSENS TLC View Post
if your quenching the blades in cool water, you are hardening (annealing) the blades and causing them to become very brittle which will increase the nicks you are getting. If you dip them in oil instead of water, you are still hardening them but not as quick as water. water shocks it almost instantly, which makes it very brittle. water will make it extremely hard but can also cause it snap, crumble etc. if hit hard. oil will still harden the blades but at a slower rate, and will not be as brittle. hope that helps...probly not the answer your looking for, but thats what i know.
happy thanksgiving!
Well, of all the replies in this thread, yours is the only one that actually addresses the original topic. Thank you for that. It is also good information to know.

I'd still like to know though, if sharpening, over time, will soften the metal to any appreciable degree, even if you don't overheat the blades?
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Old 10-07-2012, 10:41 AM
Ridin' Green Ridin' Green is offline
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Originally Posted by MOturkey View Post
Well, of all the replies in this thread, yours is the only one that actually addresses the original topic. Thank you for that. It is also good information to know.

I'd still like to know though, if sharpening, over time, will soften the metal to any appreciable degree, even if you don't overheat the blades?
Some of that depends on whether the blades were originally through hardened, or surface hardened. Obviously a surface hardened blade can have the harder outer "shell" worn, or ground through over time or with careless sharpening. It also depends on the composition of the steel alloy used.
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  #9  
Old 10-12-2012, 09:49 PM
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cpllawncare cpllawncare is offline
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Originally Posted by Ridin' Green View Post
Some of that depends on whether the blades were originally through hardened, or surface hardened. Obviously a surface hardened blade can have the harder outer "shell" worn, or ground through over time or with careless sharpening. It also depends on the composition of the steel alloy used.
That is the whole deal with making a truly great blade, " The metals composition" like anything cheap metal equals cheap blade.
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  #10  
Old 10-06-2012, 02:25 PM
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Florida Gardener Florida Gardener is offline
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IMO there isn't need for razor sharp. I sharpen mine till the edge is sharp, and get a solid 8 hours of machine use, most of the time 10. Razor sharp is gone after you start the first lawn.
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