I wonder if it is possible to some sort of Rockwell Hardness test on the edge
That’s a creative idea right there. I never would have thought of that. [quote quote=41427]
He talks about excess heat at the micro scale which is both unobservable and unmeasureable but certainly exists.I’ve read this opinion on the web a few times, including some impressive claims of very high heat at the local level. I have also seen it refuted vigorously. Parts of the argument on both sides made some sense. To it, I’d add that it’s possible that the work-hardening that is claimed to happen at the very edge would need to be considered as well if someone is claiming that the localized heat is changing the heat treating and temper i.e. is the alleged annealing countered by the alleged work-hardening? To make sense of it, I guess the first thing we should ask is if our knives are behaving as though they were annealed. To most easily test it, we should take a hardened, sharpened blade and anneal it to see how it performs. Ideally, we’d have two identical blades from the same batch and we’d sharpen both, anneal one and then test them for edge retention. [/quote]
I’m not a physicist or engineer, but I find it pretty hard to believe that a manual sharpening process on the Wicked Edge really generates enough thermal energy to ruin the heat treatment of the edge. The heat capacity of the steel at the edge is relatively small (meaning that it only takes a bit of energy to generate a relatively large change in temperature) but that also means that it only takes a small amount of cooling to dissipate that energy and keep the steel near room temperature.
I wonder if a local temp could be measured with one of those infrared temp meters. Is there a difference between “over scrubbing” vs. alternate long pass techniques. It interests me because there is no getting away from physics and accurate answers as to why blade edges sometimes chip and sometimes don’t are elusive. I keep thinking of the paper clip band demos.
Of course, I may be over thinking it all together but there are people way smarter than me who consider these effects. Roman Landes supposedly participates on the hypefreeblades forum and I will see if I can engage him. Failure mechanisms are fascinating. it brought down the shuttle and stopped the SSTO program.
In looking through hypefreeblades I came across this great photo (with more in the link) and just had to share.
http://www.hypefreeblades.com/forum/viewtopic.php?f=4&t=849&start=10
I love SEM images of blades. They really show the plasticity of steel.
Don’t get me wrong…all this theoretical physics of knife sharpening is interesting and makes for fun conversation, but why would you ever even worry about this stuff? Sorry if I’m being an idiot. It’s way beyond the scope of the Wicked Edge Forum helping Wicked Edge users to sharpen knives with their WE Systems. Especially if your knives are taking and holding a sharp edge using the Wicked Edge System. Why would ever think about this stuff? If I had a problem with a knife I sharpened, first thing I’d consider was my technique or how I handled the knife. Then after that and a hole long list of other things, I can’t imagine ever thinking I overheated the edge on a sub-microscopic level to cause edge failure??? Sorry… there’s too many other cool things that actually impact my sharpening experience to consider.
I do love SEM photos, though!
Well, I am an engineer and have been chasing these kinds of things for 30 years. On a specific WEPS question, I just got a new Kramer Essential AEB-L with double cryo, I sharpened it out of the box on WEPS, real nice edge, used it twice in the kitchen (nothing crazy), put it back on the WEPS to do some bevel thinning and found a small chip. Pissed me off. I use a 250x USB scope. I left the chip instead of doing all the steel removal but it reinvigorated my desire to try and figure it out. Its the same reason I get pleasure in growing better tomatoes in my garden.
That gives me a little more insight in your drive. (I also have some Kramer Essentials in FC61, [his VG10], very nice knives and very sharp). You failed to share how you sharpened your Kramer Essential on your WEPS. Those kind of details help others to help you solve your issue and helps others who read the forum to learn from your experiences. Wouldn’t you look for a possible solution here first before you jump to theoretical physics and a failure in the double cryo phase of the heat treatment? Certainly a practical solution you can use to overcome an issue like this in the future would maybe be more helpful to you an others then a discussion on a theoretic level that has little bearing other than it’s intellectually stimulating, oh, and fun for you?
I am not sure how to respond without getting into an argument but I will try. I am not asking for a solution, I am only looking for discussion which is what forums are for. I am not sure why you keep asking why I am interested in the variations which may affect the long term viability of kitchen knife edges. The WEPS techniques are pretty straight forward and I have done probably 100 sessions in plenty of scenarios. I suppose the WEPS forum is the wrong place for this. As the moderator maybe you can tell me what this forum is for.
BTW, as far as I know FC61 is not VG10, it is AEB-L. FC is Fine Carbide and 61 is RHC.
Man, that’s a bummer. What kind of cutting board are you working on? Some of the plastic boards can be very rough on knife edges.
Redheads as long as I have participated in this Wicked Edge Forum, long before being moderator, we forum participants and contributors have always been about helping to find and provide solutions, and learning while doing this. I don’t know what else to say. I apologize for my assumption that you were sharing with us because you sought our help, a solution, to a knife sharpening issue with your Wicked Edge System. As you say, maybe this is not the right forum for your discussion of the long-term viability of a knife edge. Actually, maybe just the wrong thread. I’m sure there are plenty of this Forum’s Participants that find the subject matter interesting. Possibly the discussion deserves it’s own Topic?
As for the steel in my Kramer Knives, when I was sent them in exchange for several Miyabi 5000MCD Birchwood Knives that I was unsatisfied with, I was told by the Zwilling Representative, my Kramer Euroline Essential Collection Knives they were sending me in replacement were VG10 steel hardened at HRc61. I read that there is some discussion that the steel may be AEB-L, and some say VG10. So you may be right and I may be wrong, either way, I apologize.
Redheads:
I just started a Forum Topic: Long Term Viability of a Knife Edge (Metallurgic Theories) Under Thoughts/Theories/Science Related to Sharpening which is in the Techniques and Sharpening Strategies Forum. I invite Redheads and others to continue this conversation with our Forum Members there. There are many knife sharpening issues we come across that are not WEPS related or WEPS solved. A variety of metallurgic issues are common. This is a good place to share these issues, concerns and theories.
Thinning a blade is a task best suited for a belt sander, where quite a bit of material can be removed in a short time. Where the blade has a grind that is more complex than an FFG kitchen knife, you’d need some special fixturing as well. I’d send you directly to Josh at Razor Edge Knives, knowing that he does outstanding work.
For the FFG kitchen knives, I have a 6" - wide belt sander. I hold the blade flat against the belt, with my finger tips applying light pressure right behind the edge. When I feel heat starting to build, I remove the knife from the sander and dip it in a pitcher of water.
I did about fifteen very inexpensive 7.5" Chicago Cutlery chefs’ knives like this which I gave as Christmas gifts. They come with an already-thin bevel shoulder at about 0.025" and I thinned them down to between 0.010" and 0.015". Several recipients have said it was the best knife they’ve ever used. Of course, they’ve probably never even held a knife that thin, because only the best steels could stand up to regular use with an edge that thin. The steel in these knives is pretty good and they are a joy to use. I gave them with a promise of free sharpenings for life. Mine, not theirs.
Unless the face grinds are relatively steep, as with a narrow-bladed folder, each sharpening probably removes less than 0.010" at the apex, or about 1/4 of a millimeter. (This is about the average depth I see with typical chip damage.) Chips are supposed to be an unusual occurrence, compared to normal wear, so it should take quite a few sharpenings for the thickness of the blade at the bevel shoulders to be a factor. This would indicate that the knife is getting a lot of use and we must keep in mind that this is a consumable item. They don’t last forever unless you keep it in a display case.
Tom, thanks for sharing this. It reminds me that my experience (or actually “lack of experience”) is very limited because I sharpen almost exclusively FFG Kitchen and Chef’s knives. I forget to consider the various grinds involved in EDC knives let alone all the other shaped knives like hunting knives, and fishing knives. Everyone of those is certainly more complex than FFG knives when it comes to a regrind.
Readheads, I think thinning is definitely possible, depending on what you mean by it. If you mean just reprofiling a knife (i.e. putting on a new bevel with the same angles on both sides), I guess we both do that regularly. If you mean putting on a new bevel with higher angles, it depends. You are restricted by the physical possibilities of the WEPS (depending on the version you have and possible attachments, but say, 13 degrees) and the time you have 
. The higher the angle, the lower the new shoulder and the more steel you have to remove.
Which also brings me to a question: Marc, what do you mean by (thinning) the profile of a knife? I agree with you (I think) and others that if you want to reprofile an entire blade (i.e. put on a new bevel that requires you to remove metal from the entire blade), there are more appropriate tools than the WEPS, like a belt grinder.
Which does not mean it’s impossible. In fact, these day I am watching in amazement photographs on the Dutch knife forum by a guy who is reprofiling an entire blade by hand. And he is aiming for a flat edge, not a convex one.
I couldn’t agree more.
And could somebody please explain to me the difference between a bevel and an edge? (Some time ago already, I was corrected by someone who said I was mixing up a bevel and an edge. In these cases, Google is often your best friend, but in this case it only confuses me more when I encounter discussions on bevelled edges or discussions throwing in the concept of a chamfer (versus a bevel, not versus an edge) only to confuse more.)
MarK76 by (thinning) the profile I meant thinning the knife so the width or thickness of the knife’s steel above/behind the shoulder is narrower. When you do this with the Wicked Edge you are really grinding or adding/profiling another bevel above/behind the knife’s cutting bevel. As you remove metal this extends this new bevel closer and closer to the knife’s edge. You can use the knife with the additional bevel and it is thinner than it was. Or eventually if you continue to remove metal, as these two bevel sides are extended towards the tip, it will become the new edge or apex of the knife.
By the way Mark76 the way the Forum mechanism adds quotes from the above post, to your forum response, it does sometimes place the wrong writer as responsible for the paraphrase quoted. In the case I refer to I am given credit for saying something Redheads wrote. I have noticed this in other instances too.
By my understanding, “the bevel” is the flat, slanted, narrowing sides of the knife ground into the knifes actual grind or shape. The bevels can be extended right to the apex where it becomes the edge. It also can be in incorporated with other bevels and not extend to edge. The point where the two opposite side bevels converge at the apex is the knife’s edge.
Thanks Marc, I think I now get what you mean. And thanks for explaining the difference between an edge and a bevel.
I don’t know whether in this case the forum software screwed up or I did. I was just editing my previous reply in order to get both the quotation and the responsible author right. I hope it is ok now. But that is indeed not easy to do with the current forum software. I’ve opened a new topic on that.
I have thinned knives on several occasions using WEPS, admittedly and not proudly, with the best looking results. Here are some photos of one of my efforts done on a "Richmond Artifex Santoku in AEB-L. It’s a rather hard, tough steel. I wore out my WEPS Diamond Stones prematurely and scratched the knife badly. So much for the cosmetic character of the knife. In these photos you can see the two distinct bevels. As the profile of the knife changes along the knife’s length the shape and eveness of the thinning bevel also is affected. This can be seen by the shape of the bevel towards the heel of the knife.
[attachment file=“Thinned Edge or Second Bevel.jpg”]
The bad scratches on the knife’s sides towards the tip are from when I attempted to widen the thinning bevel “free hand” using an “Atoma” Diamond Plate Stone. [attachment file=“Second Bevel to thin edge.jpg”]
The bottom line, it was a good learning experience and the knife is thinner and performs better, with less effort. It ain’t no beauty but it is a beast! It works great on BBQ spare ribs.
I still consider getting a belt sander so I can attempt to do the job correctly, as Tom does.
I intend to purchase one of those AMK75 belt grinder setups for knife thinning and to experiment with free hand work. It’s on a (long) list of things I hope to purchase some day.