Thread: belgian coticules

Joe,
I based my comments on the scratch fineness not only from conversations with Randy but also my Rabbi friend. He is very particular about the smoothness of the edge itself becauase of Kosher rules and said he cannot use diamonds becuase in theory at least it leaves minute little nicks (scratches) which are not allowed. He seemed to favor the more rounded grits. He also was one that found great variation in Belgians. The quarry does offer what it calls "Kosher grade" stones but at even higher prices.

My Rabbi friend was very impressed with the new Thuringen samples (shamless plug here) I sent him for testing. I am placing an order this week for 2 x 8 and 3 x 10 stones from Thuringen Germany. These are basically the same composition as the early Escher hones.

Tony

Originally Posted by Tony Miller

Joe,
I based my comments on the scratch fineness not only from conversations with Randy but also my Rabbi friend. He is very particular about the smoothness of the edge itself becauase of Kosher rules and said he cannot use diamonds becuase in theory at least it leaves minute little nicks (scratches) which are not allowed. He seemed to favor the more rounded grits. He also was one that found great variation in Belgians. The quarry does offer what it calls "Kosher grade" stones but at even higher prices.

My Rabbi friend was very impressed with the new Thuringen samples (shamless plug here) I sent him for testing. I am placing an order this week for 2 x 8 and 3 x 10 stones from Thuringen Germany. These are basically the same composition as the early Escher hones.

Tony

I suspect that what your friend says may be somewhat of a legend. A .5 micron makes a much smoother edge in terms of the size of the microserrations. There are more than 4 diamond teeth per coticule tooth. That would show up under high magnification. We know that every edge has such teeth, so there's really no such thing as a smooth edge. It's like comparing a saw with coarse teeth to one with fine teeth. Neither is really smooth, but the one with the fine teeth is closer to it.

We both have a scientific background, so you can understand why I insist on things making sense scientifically.

I'm looking forward to those Thuringen stones. I think I'd like a 3" one. That's a nice length, too. It should make short work of any honing job.

Joe,
The science thing does complicate many things. I used to be able to just take things at fae value but now always need to see proof. I think what his point was that one "may" leave rounded, vs. sharp egded striations. I did say in theory though as his rules are based on tradition. I do know he probably has the largest collection of stones and hones seen anywhere as his role is in teaching other Rabbis how to prepare their knives.

The order for Thuringens has been placed with a 10 day estimated delivery. I'll keep you posted.

Tony

I can totally see where the .5 Chromium Oxide paste may give smoother serrations equating to a "smoother" feel to the shaver, but I think that main variable there is the acutal shaver and his skin and the feeling between the blade and the skin.


I will have to try this out though, see what I like better.

I wonder if the way Randy does his paste sharpening up to the .25m diamond and then "toning it down" as he calls it with the .5m chrome oxide doesn't acutally serve to dull the blade from the .25m diamond edge but just polishes it with the .5 chrome oxide paste, smoothing out the serrations to create a super sharp but super smooth edge.

We should all donate some money to get some time on an electron scanning microcope and check this stuff out I have one at my school I could prolly buy some time on.

Originally Posted by Tony Miller

I used to be able to just take things at fae value but now always need to see proof.

For me, it's not so much a need to see proof as to understand why something happens. Two things bother me the most: when something goes against logic; and when something goes against fundamental science. When that happens I usually question the person and explain the fundamental principal involved, just to make sure I understand what the person is saying.

Originally Posted by 72miura

I can totally see where the .5 Chromium Oxide paste may give smoother serrations equating to a "smoother" feel to the shaver, but I think that main variable there is the acutal shaver and his skin and the feeling between the blade and the skin.


I will have to try this out though, see what I like better.

I wonder if the way Randy does his paste sharpening up to the .25m diamond and then "toning it down" as he calls it with the .5m chrome oxide doesn't acutally serve to dull the blade from the .25m diamond edge but just polishes it with the .5 chrome oxide paste, smoothing out the serrations to create a super sharp but super smooth edge.

We should all donate some money to get some time on an electron scanning microcope and check this stuff out I have one at my school I could prolly buy some time on.

Interesting.

I think the real problem is the use of language. To me a rough edge is the opposite of a smooth edge, and I can see that under a microscope. But what does it mean when something feels rough? If it's the way a rough edge feels, then the edge done with a finer grit can't be rougher. That's my interpretation. If t's the way the cut feels, the sharper edge will always cut more easily and feel smoother. So, I basically don't understand what someone means when they say a sharper edge cut s rougher.

I wish I had access to one of those microscopes. Do you actually have to pay to use it? How much?

Before you use the microscope you should look at how Prof. Verhoeven did his experiments with that kind of microscope. www.mse.iastate.edu/fileadmin/www.mse.iastate.edu/static/files/verhoeven/KnifeShExps.pdf

Joe,
First, thanks for the challenges, it makes exploring topics like this fun.

In the case of my friend he is looking at this from a different persepective that we are. For you and I, it is the fundamental point of more scratch lines per inch equals a finer or smoother edge.........more and smaller to us equals an edge closer to being perfectly smooth and free of scratches altogether. The theoretical "perfect edge". For him it is the difference in the shape of the scratches, not the number. To him (if I understand correctly) the diamonds leave sharp edged scratches, no matter how many or how fine is not the point. Each scratch is basically a very, very small nick. Kosher laws do not allow any nicks in the knifes edge no matter the size.

For Randy (I'm guessing here) it is simply the empirical approach......how it feels on his face.

I am always caught in between. I usually go with the gut feeling approach of what seems to work best.......BUT, really need to understand why in order to feel comfortable enough to defend, or refute it.

There are lots of other factors at work that may skew the facts. Maybe the 0.25 edge is so sharp it catches more on the skin making it feel rougher, maybe the ultra sharp edge does not strop as well for some people with the technique they use now, maybe it rolls so quickly it does not stay sharp. All of these factors could go against what the science of sharp tells us.

I do very much enjoy these types of discussions....I deal with science and detective work everyday in my "real" job and enjoy finding out why things happen. I made my original post about rounded vs. sharp simply to throw out the comments I have heard other places.

Me? I use the 0.25 pastes and sharp cutting garnet based stones because I KNOW they are sharper <g>

Tony

Originally Posted by Tony Miller

For him it is the difference in the shape of the scratches, not the number.

Ah! now I get it. It's whether something is philosohphically a sharp or smooth groove, not whether the blade actually exhibits nicks. At some time, the need for an edge not to be nicked may have been associated with cleanliness or the least amount of pain to the animal. Like many things in religion, it seems that the symbology may have taken on more importance than the original purpose.

Maybe the 0.25 edge is so sharp it catches more on the skin.

I was thinking this myself, but I didn't dare raise it because it takes us in an entirely different direction on what constitutes roughness.

I do very much enjoy these types of discussions....I deal with science and detective work everyday in my "real" job and enjoy finding out why things happen.

Me too. Understanding the way things work is essential for me, and I'm used to drawing that information out of experts and presenting it in an understandable form.

<<< Ah! now I get it. It's whether something is philosohphically a sharp or smooth groove, not whether the blade actually exhibits nicks. At some time, the need for an edge not to be nicked may have been associated with cleanliness or the least amount of pain to the animal. Like many things in religion, it seems that the symbology may have taken on more importance than the original purpose. >>>

Exactly! That covers his reasons...........now Randy may be another case which could touch on how it feels against the skin.

Tony

In Arthur Boon's "personal observations" he says that Dovo hones its razors "on a very fine Belgian Old Rock and succesively on a even finer one, called Escher waterstone."

Do people on this forum agree that the escher is finer and more of a finisher than the coticule?

Tony, would that also be true of your Thuringens?