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Knife sharpening to 20-40 BESS detailed
#1
By request of one of our customers we've made a short video documenting sharpness of his Reate Horizon-Ti in M390.
This one:




This reminded me that I shamelessly used part of Mike's video from his YouTube channel in another our video.
Better late than never: Mike, apologies for not asking for your permission, I hope you don't mind, do you?
It's this one: https://youtu.be/4irTV1xZ-EM

But back to that Reate - as long as we were documenting sharpening it anyway, on its example I've detailed how we sharpen knives to sharper than razors, using old and new photos and microscope images.
Added a few contemplative bits as well.
Hopefully you may find something useful for yourself out of it.

Sharpening steps are detailed on our Australian forum:
https://www.australianbladeforums.com/vb...ailed.html

Unexpectedly, we've encountered a funny situation with the edge oxidation, because of which we cannot deliver a knife to the customer same sharp as it comes out of our workshop. Though we do get sharper than razor edges out of our workshop, I am yet to find a way to deliver them to the customers.
Owing to the oxidation, sharpness drops a little by the time the customer gets his high-end knife, and the edge has just a Gillette DE razor sharpness, not sharper (no showing off meant).

With mainstream steels the oxidation can be removed by stropping on a clean linen/jeans/leather, but this doesn't seem to work with the high-end corrosion-resistant steels.
I can restore initial sharpness by stropping on a leather with #100,000 diamond suspension, stripping off the oxide layer, but the restored sharpness lasts for a few hours, and drops back as soon as new oxide layers form. Actually this is an expected behavior from the Chromium added for corrosion resistance.

This oxidation challenge is a new area for me, came to my attention only when we started getting sharper than razor edges, and I do not have a solution at the moment.
Any advice pointing in the right direction will be much appreciated.
http://knifeGrinders.com.au
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#2
Umm... Wow!  OK.  Hmm... Impressive Mr. KG.   2xthumbsup

To be honest, when you have mentioned some of the numbers you have obtained in previous posts I had my doubts.  But, errr... umm...  huh.  Damn, that's sharp!   Woah  Congrats.  

I wonder if a thin coat of Mobile 1 oil would help with oxidation?  In some cases Mobile 1 is amazing stuff.  There has to be some rust inhibitor that would work long enough to get it to the customer.  If it is truly oxidation, anything to prevent air contact should help.  Could the problem be metal memory?  That would be a different matter.
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#3
Thank you Grepper, such a spirit-stirring comment.
Feels weird remembering times when I was pissed off at myself for not being able to get under 100 BESS... nowadays it is when I don't get under 50 on the first attempt.

Don't know why I didn't think of sealing the edge. Will experiment with what I have at hand, and I happen to have the Mobile 1 oil.
The solution may be simple
http://knifeGrinders.com.au
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#4
You've discussed the oxidation problem on stainless steels. Does it happen on non stainless as well?
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#5
Is it metal memory or oxidation or all the above? Its difficult to separate the two even when availing oneself of a very most excellent edge sharpness tester as manufactured by EOU. It would seem that the two can exist exclusive of each other or in combination. We've seen instances, as in several, where the sharpness of an edge can measurably decline progressively over the matter of a few minutes as in 10 - 20 - 30. We assumed this was due to metal memory. We have repeatedly seen how a brand new and unused DE razor blade, left out of it's wrapper over night can decline 10 - 20 points and this in "its a dry heat" Arizona. We assume this is due to oxidation. Obviously, a newly sharpened edge left out for some period of time could be subject to both effects.

At first blush, with me2's question concerning the effects on non-stainless we say "well sure it would" with regard to iron contents being likely higher in non-stainless. But then we thought, well maybe not. Maybe it's not that sort of oxidation. Knife guys, us included, like to think of oxidation as rust. There are all sorts and forms of oxidation though i.e. the build up that occurs on a copper surface, and many of these other oxidation forms are not destructive. So maybe stainless is subject to these other oxidation forms and non-stainless is not. Maybe rust isn't the culprit here. 

As you can tell from this post, we at EOU have few answers, just more questions.
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#6
From what I know, oxide layers on stainless steel are thicker compared to that on non-stainless, but I haven't got enough data yet.
We are too early into the subject to say anything conclusive.

For now, out of practical necessity rather than firm data, we draw demarcation between the oxidation and metal memory at the 20 BESS decline, and <= 20 is attributed to the oxidation alone.
Because the high-end knife owners are so demanding, having sharpened their knives I let them rest on a shelf overnight, and send back home only when the BESS decline in 10-12 hours is < 20-30 BESS.

Timing sure matters: by BESS readings, oxidation on s/s reveals in full in 2 hours after sharpening; while metal memory events we've seen coming to maximum in 10 hours (8 hours was not always enough)...
Well, we liked to think that the first 2 hours are more specific for oxidation.
But now Mike points to one more metal memory specific time of the first 30 min, obviously Mike likes to muddy the waters.  Huh

We are learning to distinguish between the three:
- oxidation;
- the edge apex metal memory;
- the foil/wire burr, which is often considered a structural element of the apex.

I hope the new edge-rolling tester can help with this.
http://knifeGrinders.com.au
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#7
Sorry for the confusion created by our metal memory recollections KG.  Smile More importantly I forgot to mention your excellent video. So here it is. That is an excellent video and result. Thanks for sharing it!
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#8
I started thinking last night on the drive home about your work KG. That was sometime after I dashed off the amending post at work that immediately precedes this one. Thinking is always a dangerous exercise for me and, by extension, often for those who work with me. I began by thinking about the differences in time scale that we have observed with edge rolling that we have attributed to "metal memory". I decided that we should regard this as no surprise with regard to the differences in the metals we work with and the sharpening skills that you have demonstrated versus our own. Differences should be not only "no surprise" but expected. 

We have always concentrated our research and efforts in dealing with mid-level quality and price stainless steel knives. This material because, that's what the greatest number of knives in existence today are centered around. We're like the old-time preacher who spent most of his day frequenting bars and saloons. When asked by a congregant "why?" he replied "because that's where the sinners are". We admit to small success only in converting the knife sharpening "sinners" that frequent the worlds home kitchens. We'll likely keep trying though.

But then there are the KGs of the world and all the other contributors who frequent places like the BESS Exchange. When presented with the possibilities of new and useful tools they take full advantage and then share the benefit of their work with everyone.  It takes time and often money to conduct the research, take photographs or videos and compose the prose that goes into posts. Grepper's M4 study, Ken's Viel conversion, Wade's forge, Jan's Kiln and KG's processing plant study. Max and Thomas's "no frills" reports on everyday working knives are like folk art masterpieces. If it hasn't been said before and for all those mentioned here and those I neglected to mention, thank you very much for your contributions. I will promise that others will benefit from your compositions and contributions for years.  

One more item for this far ranging post. KG you have taken sharpening to a level that we might have said was impossible a year ago. I suppose that, years ago, they would have said the same thing about a non-stop flight across the Atlantic, and then came Lindbergh. In my estimation the value of what you have been able to accomplish with edge sharpness is simply in the proof of what is achievable. You've expanded the known universe of knife edge sharpness. Thank you for your research and for sharing that research with us. I do hope that you eventually pull up just shy of BESS "0" one day though.

OK, I've gotten all those thoughts that accumulated on my drive home last night expressed and hope that you didn't find them too tiresome. What I really just wanted to say was "thank you" to you all for your efforts and hope that I've, at least, accomplished that.

P.S. Never to overlook Exchange member #1, Mr. Rupert Lucius. When the Godfather speaks, people listen.
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#9
To see Paris and die.
To see 15 BESS on the knife you sharpened.
To see Mike's comment as above.
Mission complete
Smile
http://knifeGrinders.com.au
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