Shaptoneers, please confirm something for me...

I hate tomatoes...

Well, actually I love them and digest them in some form almost daily, but I also hate them, 'cause they embarrass my high-end Wusthoff kitchen cutlery. Unless I freshly hone and steel those knifes, any mutt of a serrated knife will easily outperform my fine Wusthoffs. I store them in a wooden block, they always get rinsed and wiped by hand and are pampered like babies. At the same time, that serrated piece of junk practically lives in the dishwasher and corrodes to sharpness. Still, it cuts tomatoes very well on any day, while the Wusthoffs only really measure up when I bring them up to peak performance, a condition they loose rather rapidly.
Don't get me wrong: I love my Wusthoffs, couldn't live without them, and they cut food really well, even tomatoes. It's just that I like justice. Serrated crap sold by schmuck TV salesmen, equaling my precious babies, well that just ain't justice. And that's why I hate tomatoes.;)

For the same reason, I also hate hanging hairs. I can hone a razor on my DMT 1200 to a state where it perfoms the HHT extremely well. At that point, start honing it on a coticule with slurry, and notice how, with each stroke, the HHT-readiness of that razor is wiped away. I assumed that the principles of the serrated knife applied to this situation, very analog to the tomato observations I made above. If you remove the serrations from an edge, it takes honing to considerable keenness before that edge measures up again to the raw severing power of its serrated state.
Somehow I managed to co-exist peacefully with that knowledge. Nevertheless I often wondered if some compromise needs to be reached between striations (the razors equivalent of serrations) and a slick egde. The goal would be to find the Ueber razor edge, that combines durabilty, closeness and smoothness in the ideal mixture for my face.
Then AFDavis contibuted a link to a Popular Science Article defeating the above assumptions (or not?) I hate AFDavis.;)

Anyway, to cut to the chase, if the premise of the striations is false, than there's only one other possiblity left. A coticule with slurry must be doing something with the edge of the razor. I have my own theory about what exactly is going on, posted at Josh Earls "Coticule Chronicles", but since no one has showed any interest in that, I'm not going to reiterate.

After some further contemplation, I think the best way to be over with the "striations help the HHT" theory once and for all, is to perform a hone progression from low grit to high grit on a series of hones from one single family and find out if the HHT test does nothing but gradually improve when moving up the grit ladder. Or does the HHT passes just fine at grit 1200, worsens from there on to peak again at a much higher grit? I would really like to know. I can't think of a better hone family to perform this experiment on than the Shaptons. Unfortunately, I don't have access to any Shaptons, so I was wondering if any of the Shaptoneers on this forum are willing to perform such a test, or perhaps already know the outcome, and would be willing to share the results? I would be most grateful.

Thanks,

Bart.

Well, not to throw a wrench in the gears, but the type of hone used will have an effect on how the edge develops.

If I use the DMT C to set a rough bevel, then move to the DMT E to bring it up to a sticky sharp edge that could pass the HHT, then use the DMT EE to further refine it, then move to some .5 diamond paste, the result is generally a consistent march from dull to frighteningly sharp with no apparent steps backwards.

The Coticule on the other hand abrades differently and provides much smoother results, so your observations may not be repeatable with the Shaptons. (don't know if that made much sense...)

Also, the striation do have a function for most cutting utensils. An 8k grit polish will sever tomatoes like butter, but the softer steel of kitchen cutlery can't maintain that kind of fine edge, so you loose that cutting ability rather rapidly. If you stopped at say, 1k, the edge would last a little longer and the tiny serrations would give a similar cutting power to the 8k (for culinary applications, not shaving).

(for the record, I generally don't even bother with the HHT until I get past 8k, TPT works faster for me)

We're on the same page, Russel. The idea may sprout that I over emphasize on the HHT, but I ''m really only considering it for the sake of the experiment.
The premise is this: If striations offer a substantial advantage with cutting hair, than the HHT should reflect that. The success of that test should peak with striations, dissipate when the striations are evened out, and improve again when the edge becomes so sharp that striations don't matter any more. So I would expect a fine HHT at 1200 grit level (approximately), so-so results around 6000-8000 grit level, and peak again at 12000 and above.

Of course one can't do pyramids on this experiment, and I refrain form using the coticule, because I have strong suspicions that other principles are going on at the same time with the use of coticules.

Are you saying, that with a progression on DMT-hones, you didn't find any evidence to sustain the above premise?

Thanks,

Bart.

Quote:

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Originally Posted by Bart

After some further contemplation, I think the best way to be over with the "striations help the HHT" theory once and for all..

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The best way is to just get over the HHT - it's just a test. Unlike slicing tomatoes, it isn't useful in itself except as a party trick. It is popular because it's (a) easy (b) fast (c) has some loose correlation to sharpness.

As for the progression question, I find that HHT is best off the 1k-4k Shaptons then it goes down. It depends on the razor though. I don't worry about the HHT above about 4k Shapton - what I'm really interested in is how the hair reacts to the blade even if it doesn't pop in two immediately.

I have Shapton up to 16K. This is something I'd like to try. Now I have an excuse to be able to devote uninterrupted time down in "Razorville" as my wife calls it (the basement). Unfortunately I don't see myself getting this luxury for a week or two.

I love the HHT and actually use it every day not only because it's one of the many tests for sharpness, but also because it does have an exciting essence of parlor trick to it and I'm the amused audience. Every morning after stropping and before shaving the razor gets an HHT if anything else, then for fun. I have ultra fine blondish hair and until this year was convinced that even the sharpest razors or any razor couldn't sever my hair. Wrong. Ultra keen blades "ping" by hair now. I got better at honing.

My sharpest razor at this time is a DD Dwarf and I shave with it often. Easily passes the HHT every time.

I've heard it said that an ultra sharp razor can have an edge so sharp and so polished that it does not pass the HHT. I have trouble accepting that.

I saw Randy Tuttle earlier this year and he graciously showed me some of his wonderful collection. If I recall, he had a Hess Hair Milk razor that he said was far and away his SHARPEST razor he owned. I'll PM him and ask him if it passes the HHT. I've never owned or used a Feather blade. For those that have, do those blades pass the HHT?

Chris L

Hello ChrisL,

It was a Hess Otto's Special 200 Wedge, 5/8, single concave grind. They are no longer available, all sold out. That razor took the sharpest edge of any razor that I have honed.

Regarding the HHT, this test in no way guarantees a shaving sharp edge, sharp by my definition, not anyone else's. I have learned to use the HHT and standardized it on the 8K Norton. I do not use it for any other hone.
Using the HHT, off the 8K norton, with my hair, can tell me when the razor is ready for a shave test or the next step in my honing progression.
Each person has to develop their own set of tests and learn to correlate the results with whatever they seek.

The HHT is not just a parlor trick. Some guys have learned how to make it useful, just like the TPT, and for some people it simply is not an option. The key is standardization of your tests.

Just my two cents,:)

I forgot to mention above that I've got the 1, 2, 4, 8, 15, and 30k Shaptons

Quote:

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Originally Posted by Chrisl

I've never owned or used a Feather blade. For those that have, do those blades pass the HHT?

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Feathers don't pass HHT for me. Wal-Mart Personnas do though.

Quote:

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Originally Posted by randydance062449

Hello ChrisL,

It was a Hess Otto's Special 200 Wedge, 5/8, single concave grind. They are no longer available, all sold out. That razor took the sharpest edge of any razor that I have honed.

Regarding the HHT, this test in no way guarantees a shaving sharp edge, sharp by my definition, not anyone else's. I have learned to use the HHT and standardized it on the 8K Norton. I do not use it for any other hone.
Using the HHT, off the 8K norton, with my hair, can tell me when the razor is ready for a shave test or the next step in my honing progression.
Each person has to develop their own set of tests and learn to correlate the results with whatever they seek.

The HHT is not just a parlor trick. Some guys have learned how to make it useful, just like the TPT, and for some people it simply is not an option. The key is standardization of your tests.

Just my two cents,:)

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Ah yes, a Hess Otto's Special 200 Wedge. That was a very nice looking razor!! Thanks for adding to this post so quickly.

I absolutely agree that the HHT does not guarantee a shaving sharp edge. Others pass HHT off their DMT D8E 1200 grit diamond plates and I can pass the HHT off my Shapton 2000 I've used for bevel setting. I would never shave off those grits.

What I wonder, can a truly wicked sharp (maybe even one so sharp that comfort is compromised) edge fail the HHT? Do Feather blades fail the HHT? Out of curiousity, does your Otto's Special pass or fail the HHT?

To be clear, I do believe an edge that fails the HHT can give a comfortable or at the least an irritation free shave. Since a coarse edge (1200, 2000 grit) can pass the HHT and since an edge can shave and fail the HHT, therein lies the HHT's inability to be a uniform sharpness test. However, and here's where I think I've gone full circle to end up right where Bart started with this post and share his same question:

If an edge that goes from passing HHT on lower grit stones, to failing the HHT on polishing stones but shaving well......would that same edge again pass the HHT if polished at a higher grit or to a keener level?

Chris L

Randy will probably add more to this post, but he did confirm for me in a PM that ALL his razors pass the HHT after stropping and moreover, he will not shave with a razor that does not pass the HHT after stropping. Even though I believe a shaving edge failing the HHT can yield good or great shaves because members over time have said so, I personally have not had comfortable shaves with razors that after stropping fail the HHT.

Quote:

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Originally Posted by mparker762

I forgot to mention above that I've got the 1, 2, 4, 8, 15, and 30k Shaptons



Feathers don't pass HHT for me. Wal-Mart Personnas do though.

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Interesting. Hmmmm....I'll have to think about this some more.

Chris L

If an edge that goes from passing HHT on lower grit stones, to failing the HHT on polishing stones but shaving well......would that same edge again pass the HHT if polished at a higher grit or to a keener level?

Chris L
==========================================

IMHO the answer to that will depend upon your hair, the razor and the hone used.

Newbie here, worked on a Sta Sharp and couldn't get it to pass the HHT. It was okay on the TPT and popped hair off of my forearm so I shaved with it. I got an okay shave but I would'nt call it a comfortable shave. I have to work on it some more obviously.

I think what matters is that all of our blades are shaving quite well. Tests like the HHT are so subjective that someone else's info is essentially useless to anyone other than the tester.

I would like to know the outcome of the experiment, but it's not likely to change my honing methods.

Thanks for all the replies so far, gentlemen.

It seems this has boiled down a bit to a discussion about the HHT, which was not really my intention. My original goal for starting this thread is to find out if and where striations, or thoothiness -if you wish- come into play when sharpening a razor. The HHT tests how well an edge severs a hair, which seems at least of some relevance to me, but for this experiment that all does not matter.
If a person progresses trough a series of grits, and he performs the HHT at each grit level, then it's safe to suppose he 'd do so in the same fashion, with the same hair, on the same razor. The only variable would be the grit size of the hone. IF THE HHT JUST KEEPS IMPROVING TILL IT MAXES OUT, THEN THAT MEANS "TOOTHINESS" IS NOT AFFECTING THE WAY HAIR SHAFTS ARE PENETRATED BY AN EDGE.
IF, HOWEVER, THE HHT DISSIPATES, AFTER A CERTAIN GRIT LEVEL, TO IMPROVE AGAIN AT A MUCH HIGHER GRIT LEVEL, THEN THAT MEANS THAT TWO DIFFERENT TYPES OF EDGES ARE CAPABLE OF POSSIBLE SHAVE-WORTHINESS.
It would be a starting point for further investigation.
Like I said, I have no means to do this experiment myself. I understand that Shaptons all have the same type of abrasive medium, so I really think that would be the hones to perform such experiment. Doing it on different types of hones would be ambiguous, because of the difference in abrasive media. So I humbly beg to you Shapton owners out there, to perform such a progression, perform a HHT at each level, and report your findings in this thread. I would be most grateful.

Thanks,

Bart.

I actually use a modified version of the HHT when I hone my razors. I still own the hair when I do the test, as in the hair is still attached to either my scalp or most often my mustache which always needs a bit of trimming anyway. For me, the finer I go in grit for polishing, the quicker the razor grabs a hair. Secondary is the amount of tugging to actually cut the hair, the more polished the edge is the smoother it cuts the hair and the less tugging I feel.

The serrations or grooves left from the grit used to sharpen the edge do have an effect on the cutting but as we are not sawing our beard off, the serrations will hinder, rather than help the cutting of hair unless the razor is so dull that the only hope of severing the hair is by catching and breaking it off in which case coarser serrations should help. The smoother the surface of the bevel providing our edge is intact, the lower the cutting resistance.

My prediction is that the finer the hone, the more effortless the HHT will become provided of course that the honer does his job correctly. Using slurry type stones is an entirely different matter, my coticule honed razors rarely pass the HHT until I polish with a CrO2 pasted bench strop.


Regards

Christian

Quote:

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Originally Posted by Bart

IF THE HHT JUST KEEPS IMPROVING TILL IT MAXES OUT, THEN THAT MEANS "TOOTHINESS" IS NOT AFFECTING THE WAY HAIR SHAFTS ARE PENETRATED BY AN EDGE.
IF, HOWEVER, THE HHT DISSIPATES, AFTER A CERTAIN GRIT LEVEL, TO IMPROVE AGAIN AT A MUCH HIGHER GRIT LEVEL, THEN THAT MEANS THAT TWO DIFFERENT TYPES OF EDGES ARE CAPABLE OF POSSIBLE SHAVE-WORTHINESS.

Bart.

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My normal full on progression is DMT 1200, Norton 4K, Belgian Blue, Belgian Yellow, Escher, Nakayama. With my hair, which is thick, the HHT starts to work at the DMT/Norton level and then quickly improves at every step. I get the same results with different types of badger and boar hairs from brushes. With my girlfriend's hair, which is very thin and long, only good razors at least at the Belgian Yellow stage and above will perform well (or at all). In my experience with the hair that I have used, the performance of the HHT does not deteriorate as I move up in grits; rather it improves. Stropping the razor will also generally improve the performance of the HHT. Therefore, in my experience using the different types of hair that I have used a sharper more polished edge will perform better in the HHT than a more toothy less polished edge. I agree that the HHT is just a test, and passing it well will not guarantee that you will be happy with the way that the shave that the edge provides. On the other hand I have never had a razor that I thought shaved really well that did not pass the HHT really well. Every time I have ignored bad HHT’s (and/or TPT's) and test shaved a razor anyway have not been good experiences. Therefore, the test does provide me with useful information so I will continue to use it. I'm not sure if this helps you or not but at least it's another data point.

David

Bart,

I like the way you're thinking here, but there's a problem. I have a hard time getting an edge to pass the HHT off the coticule, but the same edge will shave very well.

I do think that the toothy-ness of the edge has a big impact on the HHT. For me, test works best off my Belgian blue, medium barber hones, or the 8K Norton. It doesn't work well off the coticule, although these edges give me the smoothest shaves.

Maybe the very toothy-ness that makes a hair catch and cut cleanly also causes the razor to drag a bit when it's hitting hundreds of hairs at once. I'm not sure... :shrug:

Also, I've tried the HHT with Feather AC blades, and they perform like a low-grit edge: the hair pops rather than slicing cleanly. Regular DE blades seem to cut the hair more smoothly.

Josh

The Coticule's enigmatic behavior is part of my reason for creating this thread.

My own experience is this: If I raise slurry on a coticule, any coticule so far, I'm almost certain to loose HHT-ability. Doing light pressure laps on a coticule with only water, restores the HHT, again. In fact, I can also feel the difference while doing the TPT. The DMT edge and the Coticule/water edge, feeling more sticky than the coticule/slurry edge. Some have stated the coticule/water is higher grit than the coticule/slurry, but I have done an experiment, and found no evidence for that claim. In my experiment, I did 100 laps on an already perfectly honed razor, using a coticule/water. Then I did 30 laps on a coticule/slurry, on the toe half of the blade (from the toe to the middle). Then 10 laps on the DMT, on the toe quarter of the blade. Inspection at 40X magnification with a high end stereo microscope showed no difference between the Coticule/water and the Coticule/slurry scratch marks. The DMT-marks were very distinct, as expected. The HHT worked on the DMT part and on the Coticlue/water part, but NOT on the Coticule/slurry part. Stropping did improve the HHT-results on the Coticule/water part from "popping" to "slicing". The DMT results and the Cotiule/slurry inability to pass HHT, were not altered by the stropping.

I think the use of slurry on a Coticule might abrade the very tip of the cutting bevel a bit. Not to such an extent that it can't be restored by laps on a Coticule with only water, but still.
That kind of contra-intuitive behavior makes it hard to use the Coticules for experiments about the raw physics of edge formation, and the way "toothiness" plays a key role with that, or not. Hence, my question about the development of HHT-results on a consistent set of synthetic hones.

My interest in "toothines" aka striations, comes from Lynn's pyramids. I know the main idea is to prevent overhoning (seemingly to be an issue with the Norton, but never found on a Coticule, perhaps because of the "tip-of-bevel-abbrasion"- that I postulated about above). But I also wonder about the prescribed ratios between the 4K and the 8K. That has to leave some 4K scratches under the 8K-polishing, right? Bottom line: are there two kind of shaveready edges? The first being a "polished toothy" one, the second being a more elaborate, evened-out smooth one. The former being less comfortable but more durable and the latter smoother, but less durable. My initial analogy with slicing tomatoes, not being as stupid as it sounds?

The experiment with the HHT is a first step to find out. It's such fun... reïnventing the wheel, that I just can't resist.:D

Bart.

To address your issues with the coticule, it's surprising to me that you don't see any difference between edges honed on a coticule with slurry as compared to those without slurry. I notice a difference with no magnification at all. The slurry produces a hazy, dull bevel, and no slurry (just water) makes polished linear scratch lines. Distinctly different with no need to magnify.

And yes, the coticule is said to cut like a 6k to 8k hone with a slurry and like an 8k to 10k hone without slurry. The grit size is not changing, just the speed at which it abrades the steel, which is comparable to stones/hones in lower grit ranges.

Raise a slurry and see how fast it turns black when honing, then try to get the same amount of blackness on the coticule without a slurry. It'll take a lot longer because the slurry is abrading much faster than the plain stone's surface. (don't do this on a good blade, use one in need of a resto or a junker).

Also, the slurry does abrade the cutting edge, which is why it isn't recommended to use the coticule with slurry as a finishing step. It is a "rough cutting" step before polishing with the coticule and water.

Quote:

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Originally Posted by Russel Baldridge

To address your issues with the coticule, it's surprising to me that you don't see any difference between edges honed on a coticule with slurry as compared to those without slurry. I notice a difference with no magnification at all. The slurry produces a hazy, dull bevel, and no slurry (just water) makes polished linear scratch lines. Distinctly different with no need to magnify.

And yes, the coticule is said to cut like a 6k to 8k hone with a slurry and like an 8k to 10k hone without slurry. The grit size is not changing, just the speed at which it abrades the steel, which is comparable to stones/hones in lower grit ranges.

Raise a slurry and see how fast it turns black when honing, then try to get the same amount of blackness on the coticule without a slurry. It'll take a lot longer because the slurry is abrading much faster than the plain stone's surface. (don't do this on a good blade, use one in need of a resto or a junker).

Also, the slurry does abrade the cutting edge, which is why it isn't recommended to use the coticule with slurry as a finishing step. It is a "rough cutting" step before polishing with the coticule and water.

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Russel,

For your convenience, I repeated my experiment and took pictures. The razor was a Pearson&co. I hope that will be satisfactory. I picked my vintage coticule to do the laps. In my first experiment, I used one I recently bought from Ardennnes Coticules. But it seemed fair to use another specimen to repeat the experiment, and the vintage one happens to be -by far- the fastest cutter(with slurry) and it does produce practically zero slurry out of its own (it's a hard bugger). I did 100 laps with water, renewing the water every 20 laps, on the entire edge of the razor. Then I put a marker line halfway the edge, taped the heel half of the edge (just to make sure) and did 50 laps with heavy slurry on the tip half of the blade. Then I made a mark at the quarter part of the blade, and did 30 laps on the DMT1200. I cannot see any difference between the coticule parts. Let's suppose there's something wrong with my eyes. Then I placed the razor under the scope and took pictures at 40X magnification. My scope does not have a picture tube, so I shot the pictures through one of the oculars. The pictures are far less quality than what one can see in that microscope. I inspected the entire parts and if I didn't knew which part I was looking at, I sure as hell would not be able to tell the difference between both coticule honed parts. The DMT is obvious enough. I included the pictures. Maybe you can tell the difference. (actually, from the pictures it may look like the coticule with water is -unexpectedly- slightly coarser, but that's just a pure coincidence. If I showed you a whole bunch of pictures from both parts, they would show that kind of variation on either part)

Rating the coticule with slurry 6K to 8K is pure nonsense. There is too much speed variance between coticules to make a grit assumption based on speed, and even then, the question remains what you would be the unity hone, to which all others would be compared. I you rate the grit size of a hone, you need to talk about scratch pattern. The only written source I read about the coticule's scratch pattern mentioned 3 micron and smaller. That supposes to correspond with 8000 grit. Of course the form of the scratches play their part in the game too. So much for comparing grits of different hones.

I love coticules. I hope that being a Belgian entitles me to some affinity with them. And, much unlike what you seem to implying, I don't have "issues" with them. I just like to explore them and come to a better understanding of those hones and of razor's edges in general. They are much more than a "polisher with water". I 've seen a honemeister in Antwerp at work, that uses a coticule in a completely different fashion (Bruno even consideres the guy ignorant to honing because of that), and yet his edges are wicked sharp and lasting. I intend to get to the bottom of all this.

Hi Bart (and everyone else),

I have been in the hospital from the 30th until yesterday so I'm a little late chiming in but I still want to chime. I am going to give you my opinion. Somehow someone may disagree but it's my opinion and I'm sticking with it. Here are my sharpening stones:
http://farm3.static.flickr.com/2260/...409333ab_b.jpg
I was hoping the last three Shaptons would have been waiting for me when I got home but no, I am still awaiting them. You can see I also have my Belgian stones. I love them, they love me and the love my cutlery:
http://farm3.static.flickr.com/2013/...86c294ab_b.jpg
I have Henkel's Four Star but as I've said, Henkels, Wusthoff, Sabatier, whatever, good cutlery is good cutlery. The tomato is an inconsistant test media as is a human hair so trying to develope a comparative test of sharpness between the two is impractiical. My knives and my razors are all in great shape but not one of them will reliably, repeatably cut one of the very thin, stretchy hairs from my head. Therfore, my hair is useless as a test media. What I usually do is run the blade along my arm with the edge an eighth inch or so above my skin. As a result I usually have random bald spots on my left arm. However, the serrated utility knife (Bottom strip, center knife) will not cut my arm hair but it is the most reliable for slicing a soft tomato. My favorite knife, the santoku (second from the left on the bottom strip) is always shaving sharp but some soft tomatoes will collapse if placed on the cutting board skin side up. I can get them all to cut if the tomato is cut first in half and then I attack the fruit from the freshly cut edge. Okay, here's my theory( and now I expose my soft, newly operated on underbelly for evisceration).

A material is never truly "cut" but rather it is torn at molecular bond lines. Every material has a bond strength that is measurable in pounds per square inch (PSI). The sharpness of a cutting tool employs two separate mechanisms which facilitate that tool's "cutting ability"

1. The finer the edge of a cutting tool, the more readily it will fit between and cleave or separate the molecules of a material.
2. The concentration force applied to the cutting edge of a tool is inversely proportional to the siize of the edge. As the area of a cutting edge approaches zero, the force applied approaches infinity.

I have read that serrated kniife stays sharp because the valley edges (between the points) doesn't touch the cutting board. While there may be some truth to this, I believe the serrated knife will cut a tomato because of the high force concentration at the points will always tear through the tomato skin.

Have I stopped making sense?

Quote:

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Originally Posted by Bart

Rating the coticule with slurry 6K to 8K is pure nonsense.

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First off: I haven't intended to offend you, I just wanted to share a differing experience.

Second: When I said "issues" I was making reference to your own claim that you find the coticule's behavior "enigmatic", nothing more.

And, I think you're misunderstanding what I meant about the abrasive action of the stone. I don't intend to actually rate the grit at any level other than what it is, what I mean is that the extra garnet content in the slurry cuts steel with a speed that is much faster than the usual "8k"coticule. So it is as if the coticule were a 6k when you form a slurry, not that the garnet cuts 6k sized scratches. And, in fact, this is the case when you raise a slurry on many abrasive stones, not unique to the coticule.

Your experiment is nice, it was thoughtful and well executed. But it is faulted by the previous misunderstanding, in that the grit size has stayed the same, so yes, they look very similar. What your pictures don't show is the amount of material each method took off of the edge, which is what I meant by the lower/higher grit ratings. If you get an old wedge or some other razor with a fat bevel I think you'll be able to see what I mean by the "hazy" look made by the slurry, and the "polished" look made by the plain wetted (I've heard the word somewhere, so I'm gonna run with it) surface.

As for the wide variance in performance characteristics among natural stones; I am well aware of it, to say the least. But it is much harder to describe to someone (usually new guys looking for "the best stone for the money that will do everything I need"), with no first hand knowledge of the subject, how the slurry cuts faster but is the same grit as the base stone, or how the stone can both set a bevel and give a fine polished edge. It's just easier to make an analogy to lower/higher grit ranges.

And sure there is documentation saying that garnet is a crystal that is an X rating on the MOHS scale, it is, on average, Y microns in diameter, with Z number of facets, and that the Coticule is comprised of between ALPHA and BETA percentages in concentration of garnet crystals. But unless you get your precise stone analyzed, your still just guessing at it's rating anyway. And when it comes down to being realistic, you just have to have a bunch of stones to compare performance characteristics and decide what kind of rating fits.

(Does anyone remember what happened to that project where there was a chart that compared the different characteristics of various stone to the Nortons and DMT's?)

Icedog,

Thank you very much for your reply. I like your pictures! I can see you enjoy the virtue of quality tools:). Actually the tomato cutting analogy was just a bad attempt to be funny, which is a flaw in my character. But your explanation of it makes sense to me, and the idea of looking at the "peaks" of the edge as spears that concentrate the cutting force in spike points to allow for better penetration is both new and revealing to me. I just finished cutting a tomato in the slowest possible motion, and I could actually see the serrations punching through the tomato skin, before the inclusions follow. The big question is: are similar principles at work when a razor slices hair? At least I can see one flaw in my previous reasoning: I assumed that one hair got trapped in one inclusion between to peaks, and that the sharp bottom of that inclusion did the cutting. How stupid could I be? A hair measures between 30 and 120 microns, while razor striations are about 10 times smaller. Thank you for showing me the light on that. The question of course remains: does "toothiness" really make a difference if applied to a razor's edge? And if so, what would be the ideal size/distribution of the teeth?
I am aware that shapton owners generally do not bother with such ideas, but just put the finest possible edge on a razor and shave while whistling Dixie. As for myself, I'd rather drop dead than slicing tomatoes with a serrated knife, and as far as a razor edge goes, except for the whistling, I have been following the "polish as far as possible" approach. I like to find out IF a "striated" approach to razor's edges makes equal, less or more sense.

Thanks again for chiming in.
I hope you make quick and full recovery,

Bart.

Quote:

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Originally Posted by Russel Baldridge

First off: I haven't intended to offend you, I just wanted to share a differing experience.

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It is true that I felt a bit patronized by your reply. But I have a great appreciation for your knowledge about all things steel and sharp and your willingness to share with others. I think we have that in common, at least the willingness to share part.;)

My statement that rating the Coticule with slurry as 6000 grit is nonsense, was not directed to you. After all, you only mentioned others rating it that way. A coticule with slurry cuts at least 10X faster than one wiith water, and both you and I are not going to start rating it 600 grit, are we?:hmmm:

Thanks for thinking this thing through with me,
We have been quibbling before. I don't take that personal, and I hope neither do you.

Kind regards,
Bart.

Nope, no personal offense taken.

As for the striations; I think that, at the lower grit levels, the uneven portions of the edge that feel like teeth may be comparable in sharpness to the final desired shaving edge so they are what's making the blade appear to pass the HHT but in reality, the main cutting bevel is much too dull (not to mention that you'd have some serious razor burn from the teeth) to shave with. And when higher grit stones are used to remove the inconsistencies along the main cutting bevel, the sharp teeth are removed, leaving a slightly duller, but much smoother, razor edge.

This can be continued up as far as one wants to, or can realistically, go (i.e. shapton 30k, Nakayama, .25 diamond). And at some point, the edge just cannot get any finer. I have yet to tell a difference between CrO and my Nakayama because, at those grit levels, the striations are almost non-existent and it's the quality of the steel and the bevel angle that are the noticeable properties.

So, to summarize my attempt to answer your question, I am saying it's possible that the teeth are sharper than the main bevel, sharp enough to pass the HHT, and that a polished razor edge returns to the same (or finer) sharpness of the original teeth but without the serration. Thus making the edge "shave ready".

Is that somewhat in line with your observations?

Russel,

What you describe is what I believe to be the foundation of "the progressive honing method". From the very beginning it always made the most physical sense to me, so I have learned to hone my razors by those rules and still am to this day. My edges shave well and last between 10 and 20 shaves before I need to touch up. Many people would be happy with that and never give the bare physics of honing another tought. But that's not me...

There's the pyramids. No doubt in my mind they result in fine shaveready edges, but I can't honestly believe that 5 laps at 8K can remove 1 lap of scratches at 4K. I could be wrong, having no experience with Nortons and all. The last thing I want is this thread gliding off to yet another "progressive" versus "pyramid" discussion, so I 'm not going to say anything more about that.

But I have another observation: Robert Chevalier, owner of a razor store in Antwerp, tutors shaving and honing classes. As I mentioned in previous posts, his method really works, and because of the success of his courses, there are probably more people in Belgium that hone with Chevalier's paradigm than those who follow one of the methods advocated on SRP. Chevalier does this:
He raises a good slurry on a coticule. Then he hones, usually without X-stroke, a number of laps on the coticule, till the TNT passes. Next he runs the razor over a piece of horn that he keeps in water. It smells awful, and I really think it is not needed, but he states they do the same at Dovo, and it serves to remove a possible burr. As a final honing step, he does a few very light laps on a pasted paddle strop, cured with red Dovo paste (that's 4 (edit) micron!, if I'm not mistaken). He doesn't do much, just enough till the razor passes the HHT. (Is he pulling some teeth out of that finely polished coticule edge??) Then he strops about 20 on canvas and a bit more on clean leather. That's it.

I saw him do it. I saw his wife do it. I have tested a razor honed by her, that I knew for sure to be dull prior to the honing (a heirloom piece that had been lying in a drawer for 30 years). It passed the HHT very well. My friend learned to shave with that razor, and it stayed keen for many shaves.

All that leads me to wonder if there might be two types of edges. The one I have on my razors as we speak, which corresponds with what you describe in your mail, and another type of edge that includes "teeth".
The first thing I need to know to answer that question, is whether "teeth" really makes a difference for cutting a hair, hence the Shapton experiment I called for. I really hope there are people willing to perform the experiment (polishing an edge with a progression of Shapton hones and performing the HHT after each hone), and start posting their results any time soon.

Bart.

I think you're on to the right explanation. The coticules have garnets in them and it's the corners of the rhombic dodecahedral shape that get cleaved from the embedded crystal and make the slurry do the cutting and polishing of the edge. The eschers have silica in them. Different crystal system - hexagonal, long C axis, equal A and B axes. The result is different and it can be seen on the steel at the end of the process. The diamonds in a diamond stone are different yet again both in crystalline family (cubic) as well as in use. The nickel plating holds the diamond in place while the steel is abraded over it. That is very different from slurry honing and the results are different. Check out the difference in coticules when the edge is dry honed vs. slurry honed. Tim Zowada has photos of the two methods result on straight razor edges. The dry honed is brighter but doesn't shave as well.

Coticule rated as a 6000? What's THAT about? I've been honing razors for years on coticules and have customers around the world who have been doing so as well. Their consensus is the coticule (Select grade) is rated as an 8k but polishes an edge to about a 10k. The belgian blue is similar. It is rated as a 4k but polishes toa 6k. You do have to use a slurry as the Belgians (and I) recommend. A pure coticule slurry stone ("cotigura"), a word I invented, is the best slurry stone to use either with coticules or belgian blues.

Hey Howard,

Nice info, thanks for contributing. Yes I saw Zowada's photos. I tried dry honing, but did not liked the results as much.
Another thing I have been trying, is to backhone on slurry after setting the bevel on a DMT, and then finish with a normal stroke on water. The results were very good, but I 'd have to build more experience with that approach and compare it to my regular honing paradigm, before I could confirm if there's any real advantage.

Is there really no one willing to do the initial experiment?
(honing a razor with a progression on all the Shapton hones and performing an HHT at each stage).

:(

Thanks to everyone for sharing his viewpoints on this one.
Although there is no final outcome, I still learned a few things.

Kind regards,
Bart.