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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Mon May 12, 2014 8:09 pm 

Joined: Fri Apr 04, 2014 6:45 am
Posts: 135
I believe you will find that is a fracture rather than a burr. Could be from a rolled over edge which work hardened the already tempered steel. When the steel hit the stones or diamond plate this is what happens as one tries to remove it from the blade. I see this regularly with stamped or sheared edges in material as the action of a dull punch or shear will work harden the edges directly adjacent to the cut beyond its normal temper. I could also be the result of a bad heat treat/quench but I would lean toward the work hardened edge causing the large fracturing.

Jamie


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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Mon May 12, 2014 11:14 pm 
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JAMIE <> No. It's a burr. I generated them over and over again, on one side and then on the other; grinding away more & more metal to get passed all the chips.



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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Mon May 12, 2014 11:48 pm 

Joined: Fri Apr 04, 2014 6:45 am
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Melampus wrote:JAMIE <> No. It's a burr. I generated them over and over again, on one side and then on the other; grinding away more & more metal to get passed all the chips.


Hi Mel,

One man's burr is another man's fracture.... LOL Unfortunately I have dealt with these conditions for the last 40+ years as I developed methods of working and forming exotic alloys for the aerospace industry. I was constantly performing Xray and other non invasive inspections along with sectional and other invasive testing on materials to determine why we might get that type of condition or other unacceptable material conditions especially in manned space flight hardware. Titanium alloys and those who are unfamiliar with working this material are some of the worst offenders but it can occur in nickle, aluminum and carbon alloys as well..Actually, this problem can occur in any material which can be work hardened. Sometimes the defects were in the original ingot. Sometimes it was inherent in a badly forged or rolled lot of material. Sometimes the heat treat was incorrectly performed. Sometimes the material was loaded with porosity, inclusions or foreign material from which a fracture could propagate. Many times, as I noted, these types of wire edges or chips as you call them were the result of shearing or trimming operations creating stress and or work hardening in the structure of the material abutting the cut. In your picture, the direction of the fracture and the creation of longer chips as you call them along with the type of edge generated after it peeled is why I believe it to be a fracture. This can also go along the grain direction of an improperly rolled raw material but would need some sort of edge nick, pore, weak spot or ?? from which to propagate. In this case the peel appears to be consistent with the curved edge of the blade. This can easily happen if someone continues to abuse (In this case the word abuse only means to cause it to roll over which is certainly going to happen it is just that some edges are more abused than others) an edge, short or long sections, by rolling it over and continually honing or realigning it which results in work hardening (Bending the area, albeit very thin area, back and forth even over a long period of time). The work hardened area will extend past the center of the back and forth worked section and into the parent material adjacent to the area until it reaches a point where the unaffected area resumes. I am assuming once you ground past what I am noting as the work hardened area you were able to get a proper de-burr and edge on it without any more of the fractured chips. I would imagine this problem might often occur on blades which are worked hard and have some sort of re-alignment done on a regular basis creating the back and forth event. On the other hand perhaps I am wrong and it was just a burr.. Either way it is time for a Scotch.

Jamie

Jamie


Last edited by fishordie on Tue May 13, 2014 1:09 am, edited 1 time in total.

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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Tue May 13, 2014 12:43 am 

Joined: Wed Feb 20, 2013 2:22 am
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Jamie<> I think that makes you the second member of this forum in as many months who has outted themselves as a metals / materials science kind of guy. It does my heart good to see us benefit from such experience without having to deal with the Sperglords that troll other forums.

Cheers,

Rick


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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Tue May 13, 2014 1:02 am 
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Welcome aboard, Jamie. I have a feeling we will be having some long chats and look forward to your inputs.

These are burrs. I'm quite confident of that. And dam big ones too!

BUT I also agree with everything else you are saying regarding fractures and work hardening. I also believe that generating hugh burrs and bending them off does leave one with fractures in the metal left behind the broken off burr that you intend to use to form the edge, so I tend to abrade the burrs in place on alternate sides before they get this large - even on crap knives with big chips where you need to grind past the point of union of the two sides. This keeps you from folding the area where the burr / wire edge is attached and causing unnecessary work hardening and fractures.

---
Ken



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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Tue May 13, 2014 1:43 am 

Joined: Thu May 24, 2012 6:20 am
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I had trouble following your argument until: "it is time for a Scotch." :mrgreen:


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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Tue May 13, 2014 6:20 pm 
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JAMIE <>
    First, a warm welcome even though we have crossed paths already.
    Second, I must reiterate RICK's sentiment as it is a benefit to have perspective from your background around.
    Third, I commend & respect you for your 40 year tenure. It is always a pleasure to encounter such as those.

The rest I will dive into. I despise arguing semantics, and I will not with you. In the sharpeners' vernacular, what I have illustrated is undeniably & unarguably a burr. It is the metal that is abraded off & over the edge. There are no fractures in the blade. If you are choosing to call this a fracture because the burr is fractured off the edge... that is your perogative, but amid a sharpeners dialect it is a burr. I can imagine your parlance as an Aeronautical Engineer would differ from we knife guys, and its always time for whiskey... though I drink Irish.

Furthermore, you misinterpreted my usage of the word chip. I never called the burr a chip. I said, I ground past the chips to generate a burr. Here is an example of the chips I have removed. If you look at the edge, you will see chips. To remove the chips, I had to grind past the chips... leaving a burr of metal as I abrade it off.

Image

Hey, look Mom, no more burr!

previous Wusthof...
Image

previous Damco...
Image



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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Wed May 14, 2014 5:51 am 

Joined: Tue Oct 29, 2013 9:21 pm
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Okay...so I probably just put a wire edge on the damn thing and it made me happy cutting paper. I am guilty of that. I did get satisfaction knowing I could fix the tip quickly. Is it possible to get an edge on these soft cheap steels? I know it's possible, I did it once but they seem to fold so quickly. Is there a point to using a stone on such a knife?

I hate to sound snobbish but I think it's kind of a waste of time sharpening a knife for somebody who is just going to bang it on a steel like Gordon Ramsey.


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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Wed May 14, 2014 6:05 am 
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Should you get paid to do it, I believe in delivering your best to the customer, irrelevant of what or how he treats it.

Some nifty work there Mel!

:)



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 Post subject: Re: 140 Grit Atoma Edge :)
PostPosted: Wed May 14, 2014 6:38 am 

Joined: Sat Mar 01, 2014 7:15 am
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Location: Raleigh, NC
So long as we're not talking about an OXO knife, yes, you can get a worthy edge on there. Even a Cutco can be sharpened well, if not perhaps by Cutco. We have a horribly skewed perception on knives here. A Victorinox, say, is not a cheapo knife. They're premium tools. Our own knives of choice, while much more premium, don't degrade the Victorinox knives of the world to junk status. The edge they can take and hold with steeling is optimal for everyday kitchen work.

I've gotten a $7 knife sharp enough to shave (and it responded well to honing). Softer steel will take a great 20 degree edge from a 1.5k-2k stone or plate that is lasting and effective. I use and will continue to use two or three Fibroxes myself and I wouldn't dare look down on them.


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