KenSchwartz wrote:


Ken,

Thanks for the above information and links, and no I guess I missed them if you had posted them elsewhere. Do I undersand where to obtain your products? Is that the product that Clay is sell here? Or do you have a separate ecommerce site somewhere?

You might remember me from my previous postings: I am the "cheaper is better guy". I came up with a mod for the WE arms that cost 5 bucks, I use red iron oxide strop compound that is used on my jewelry bench (another hobby of mine!) that costs even less ! You get the idea

Well I am preparing another post for later today where I respond to the last 4 or five posts from others. Certain statement that some have made here have caught my eye, and I want to quote them and then respond with my humble thoughts.

One thing has happened here as a result of all this discussion that has thrown me into action: I feel that my position is not defensible if i have not put it to the test. I had a sample of a 2 micron Diamond compound from some years ago sitting on my bench. It was part of a polishing kit I obtained for working platinum jewelry. I never used it for that purpose, but did try it on a few knives. I recall that I saw very little difference in those knives after the red iron oxide polish, so hence never felt motivated to by more samples or other even finer grits. i just let the whole subject fade away. But now we are all here disussing this issue. We have all sorts of issues, points of view, various vendors of product, SEMs of blades and compounds. WHEW! it's enough to make my old head spin!

In the face of all that information I am nagged by the thought, "What if I am wrong and they are right?" After all, I never really tried any compounds that purport to being sub micron. So not to be on here just blowing a lot of hot air, and being an inveterate fiddler I decided to go ahead and obtain some samples and give it a go. We will see where that yellow brick road ends. One thing for sure -->>> it ain't cheap! I have been busy on the internet and have on order sets of blank handles, leather handles, various grits in a range from Clays 3.5 down to 2 to 1 to .5 (two samples that: one Chromium Oxide, One Diamond) to a no name brand .25 and now your nice looking .25 to compare it to.. so it has turned into a $$$ project, probably 300 so far and counting! Guess now a need a good 400x stereo microscope,.. Hummm, well there goes my "cheaper is better"

Will post later with some comments in response to others POV... It will take weeks to actually test my new toys, and of course I have to wait for Elk season to see if Clay is right about all this -Dan

The compounds that I sell through Clay are the 0.125 micron CBN and the 0.050 and 0.025 micron polycrystaline diamond. Note the decimal points here - 0.025 is ten times finer than quarter micron. For other coarser compounds, just contact me via PM. My wife shares your hobby of jewelry making and I act as her tech support

Extrapolating your point of view based on a 2 micron diamond sample that didn't work out well - Well what can I say? Two microns is roughly equivalent to a 8,000 grit Japanese waterstone particle in size and this is commonly used for sharpening, so I strongly suspect that it was a 'cheap' quality product of unknown or low concentration, poorly formulated and at a low concentration. We need to give you a better perspective on 'the good stuff'. Waterstones go up to half micron particles, e.g., the Shapton 30k stones and produce a spectacular edge - without benefit of a clean room Natural stones sometimes even exceed this level of fineness and have been used for hundreds of years. I do have for instance 2 micron polycrystalline diamond and CBN products if you wanted to compare it to your earlier results too.

I'm quite confident, based on my own extensive experience and those of my customers that you are on the verge of an epiphany in your sharpening journey.

You might find this thread useful additional reading:

badgerandblade.com/vb/showthread.php/181...bic-Boron-Nitride%29

The use of these fine compounds extends to both use on precision devices such as the WE as well as freehand and belt grinder applications. Compounds as fine as 0.5 microns have been used for years in these applications for refining knife edges. Indeed I can refer to Japanese literature dating back 50 years where this is recommended for final stropping on razors. This is true for both flat and convex grinds.

Let me know if I can help you in your studies.


---
Ken



BassLakeDan wrote:

Ken,, thanks very much for the information, it is happily received here on this end ! I will check out the links you mention. Yes, I will continue on my sharpening journey, nothing stopping me now but my banker ! -Dan

Quote from Ken "... I thought I knew what sharp was, but I have proven myself wrong so many times that now I just look forward to reaching the next level."

Ken, Your statement above caught my eye.. how have you established that one blade is sharper than another? has anyone been able to get there hands on and loan us one of these ? Actually have one on order myself, it is due to be delivered just after I win the next Mega-Lotto

www.catra.org/pages/products/kniveslevel1/surgredst.htm

This is a difficult topic as no one has found a definition of sharpness that covers all cases and that satisfies all their needs for evaluation. In short, it is a tower of Babel.

Take the CATRA testing. It is essentially evaluating push cutting performance under strict guidelines. It is setup to detect the instant that a cut starts. Essentially a burst injury type of separation. It tells you very little of slice cutting performance. It also tells you little of how a blade's overall geometry contributes or inhibits the ability of a knife to pass through an object or objects of different density. So, for instance, if you cut a cucumber slowly it may not cleanly separate, but with a bit more speed the inertia will 'follow through' and you get better separation. This is different than a straight push cut vs a slight slicing motion when contacting the board. People have used string extended over a platform on a scale, and taring the platform's weight measured the point where the string is cut. This is fraught with string consistency issues, string tension issues, matching the string performance to the force range of the cut and variance along the edge, etc.

In a practical but imperfect sense, I use the ability of a knife to slice or push cut through copy paper as one index. For push cuts it is a direct downward motion perpendicular and from a point of touching the paper. I measure how far out from a pinch grip it will do this, eg push cutting 2 inches from a pinch grip. There are ways to cheat on this and edge thickness and angles change the values for equally sharpened edges. Ultimately the ideal test of sharpness is done by using the knife for it's intended task.

Not all knives are sharpened the same along their whole length, so ultimately you have to sample along the whole length. So for instance, a deba might have a less acute angle at it's heel than it's tip because the heel is used for chopping off fish heads and the tip and midsection for filleting the fish so the angle is varied along it's length in a continuously variable fashion. This CAN be done with a WE.

Sharpness is not the only goal involved in sharpening a knife. You trade for longevity of the edge, the task it will be used for and so forth. In some instances aesthetic considerations may even exceed sharpness requirements. This is a topic in itself, which can take into account both personal and cultural aesthetics. In some instances like shaving, comfort may be of equal importance to sharpness.

This doesn't even begin a discussion of defining sharpness.

---
Ken


BassLakeDan wrote:

For me there is also great satsifaction just knowing my knife is so crazy sharp and I made it that way...there is a kind of male pride knowing this. I suppose it may have something to do with a sense of manliness that harkens back to the days when a sharp knife was an indispensible tool necessary for life.This may flow from my limbic brain!! LOL!
Well done Ken! I really enjoyed your commentary, most pertinent!

Best regards
Leo

leomitch wrote:


Yes i agree Leo that Kens Quote above is a classic and very well stated.. I am going to print it out for future reference. Actually I think it is so well done that it needs to be in some sort of Reference Archive here on the board!

As for your man-cave perspective well don't look over your shoulder, as something might be gaining on you, and her knife might be sharper than yours !!!!

Yes I agree that knowledge like this should be kept somehow on this forum in a safe reference area...I shall speak to Clay about that and see if it can be done.
As for her gaining on me, let her come! My knife is bound to be sharper than her knife, but maybe not as sharp as her tongue!! Whoops! I will pay for that I have a feeling! LOL!

Leo

+1 on everything Ken said!!!

And we haven't even touched the subject of aesthetic polishing vs. establishing "true" grit edges!