Assess coticule quality?

Hi everyone,

I am trying to touch up the edges of two razors on a coticule. The first is a Dovo I got from Lynn a couple of months ago (was a perfect shaver upon arrival) and the second is a TI I bought new about 3 years ago. Now that I have felt what shave-ready feels like (the Dovo), I can confidently say that the TI has never been that sharp.
After considerable work on the coticule (30-50 laps with and without slurry), both razors pass the marker test and "almost" pass the HHT: hairs split but do not pop... and the shave test felt rough :eek:
Because this is my only hone, I cannot tell whether the poor honing job is caused by the hone, my technique, or both... Therefore, is there any way to assess the quality of a coticule, next to the honing result? I have read somewhere on this forum that the quality of natural hones can vary... As all coticules look more or less the same, I suppose it does not make sense to put a picture of my stone online... wait, there is a small grey-black spot (about 0.5" by 0.25") on the (yellow) honing surface :hmmm:

Any ideas?

Thanks in advance for your assistance!

Best regards,

Tim

While I do love my coticule I wouldn't try shaving off the stropped edge. I at least use the CrOX strop with 10-15 laps afterwards or even finer hones (Thuringians for example).

Good question.
Different veins do exist and each vein caries a number of coticule layers, separated by Belgian Blue stone.
In the old days, raw coticule was always triaged, based on the layer it was harvested from, and even then they differentiated in purity of the stone. Some layers were considered "razor quality" while others were used for honing other tools. Even within razor hone category, there were different grades. But those were the old days. People were honing razors entirely on coticules, without going to coarser stones when more work was needed. A razor quality hone needed to be fast, very fast even, because you can't put pressure on a razor blade while honing, in the way you can push down on, let's say, a chisel, or a butchers knife. So, a lot of the gradation is about cutting speed, which is not of great importance, because nowadays, most of us use the coticule merely for polishing purposes and not for bevel restauration. I have a few different stones, and the difference in cutting speed is very obvious. You can tell something about the speed of your coticule if you observe the slurry. The slurry of fast coticules will turn grey (from the metal particles it is eating) almost instantly. Others will take many laps before you notice a little discoloration.
But they differentiated between fineness too, in the old days. I have a copy of a book that describes many different coticule layers with comments about the fineness of the hones they produce. At Ardennes Coticule (the only operational quarry) they don't sort the hones today. I think it would be very difficult to start doing that again, for the entire production, for reasons of the modern quarrying techniques they use. (dynamite as opposed to dangerous, but meticulous mining of stones 30 meters below the surface in unstable mine shafts) They have plans though, for grading at least part of the production, especially the part that's meant for razor aficionado's .
The question remains: how big are those supposed differences in fineness? From where I stand, not all that big. Perhaps even, not noteworthy big. I have access to 7 different coticules (and more to come), and there's not a single one that refused to put a good edge on a razor that required anything else to be qualified shaveready. Sure, one can still step up to Chromium Oxide, or other types of finer (and rather expensive) hones and push a razor further up the keenness ladder, but one can also shave right of any of those coticules for the rest of a lifetime and that's exactly what I'm going to do.
It's impossible to tell, without some serious double blind testing, if and which one of those 7 coticules puts the finest edge on a razor.
As it stands, I have 8 identical razors on the way, and have planned a series of comparative tests, together with a straight shaving friend. Not because I doubt the quality of certain coticules, but because it seems like an awesome and fun idea to do all kind of experiments with different honing methods and different coticules.

Nevertheless, I think you should post a picture of that coticule, just because many of us like watching them :).
As for your specific problem with honing your razor, i'll put that in another post, because not every one likes to read long posts.

Bart.

For the longest time my coticule was the last stop in my honing process. I never needed anything more as it put the ultimate edge on most of my razors. Even though I have added some more stones and they provide a slightly different result in general my coticule is still my go to stone for final polish. But as to your question, there are coticules that give a vastly poorer result. It would depend on the distribution of the garnets, the size of the xtls and the type of xtls and the type of garnets.That is why it is very important to know your stone provider and trust in him. As to whether your problem is a stone problem or technique problem or a combination the only answer is to have someone highly skilled use the stone and let you know.

Tim,

You should know that, while a coticule with slurry removes metal efficiently, it also has a tendency for rounding the very last bit of the tip of the cutting bevel. A perfect shaveready edge starts with a bevel tip width of 0.5 micron or less. Clearly coticule slurry causes the bevel tip to broaden a bit to a width that shaves but only marginally. The denser the slurry, the more pronounced that effect will be. Please bear in mind that the granats (a sort of spiky balls that do the grinding, mixed with water to form the slurry) are approximately 15 microns in diameter. Pushing your edge through that slurry is a bit like pushing the edge through mud. It eats metal from the sides of your bevel, but also from the tip.
That said, the frist thing to try is to start with a rather dense slurry, but never denser than coffee cream consistency, do 30 laps or so, adding drops of water as soon as that slurry starts to thicken. Keep at that, till the TNT or even better, the TPT starts telling you, that you've maxed out with what your doing. Then, lower your already low pressure to the bare minimum. Performing the strokes with some speed helps. (You can turn the razor over the spine as slow as you wish, but the strokes are generally lighter with some speed). Watch that slurry, don't allow for it become any denser. See if you can gain a bit more by performing another TPT. (Stop using the TNT at this point, for it may dull what you are gaining). If you maxed out again, then start adding 2 drops of water every 10 laps, slowly allowing that slurry to dilute till the point where you have only water. It should take you about 70 to 100 laps, from slurry to water. Now, rinse that razor, wipe it dry with some tissue paper, and get to your strop. Do at least 50 laps with enough pressure to feel a clear draw. Keep that strop very taut. After that strop another 30 with just the weight of the razor for pressure.
Try the HHT.
You should have a great shaving edge now.
Please keep me posted, I have a few other tricks up my sleeve, that were successful in countering the dulling effect of coticule slurry.
I believe it is the reason that most people do the initial bevel work on a DMT1200 or another fast cutter, and use the coticule only with water for polishing that already sharp bevel to shavereadiness.

Just a simple question.... have you lapped that coticule flat?

If not, then do so. It will make a big difference.

Thanks a lot for your help guys!

@Bart: For some reason I cannot produce slurry thicker than let's say regular milk (both in consistency and color)... With the small rubbing stone (coticule) I cannot get it as thick as coffee cream... also, the slurry does not turn grey during the honing process.

@Randy: How should I lap the coticule? Does it suffice to rub the small coticule over the honing surface?

Tonight, I will give it another try...

Thanks again,

Tim

I have used a more haphazard version of Bart's Coticule method and I can shave off my edges.
I know I could do better (I'm still a very green learner) by being a bit more methodical.

Here is how to lap a hone

http://straightrazorpalace.com/basic...ing-101-a.html

Tim,
If your coticule does not produce slurry easily and it does not turn grayish from metal particles, than you have one of the slower stones. With some coticules, the rock that bonds the garnets together is so hard that it's difficult to raise a good slurry. With other slow coticules, the garnets themselves appear to be slower. From the information you provided, my bet is that you have the former case. Probably a great polisher, but not much of a metal eater.
But, my friend, do not despair, a stubborn horse often rides better then an indulgent one, once you learn how to tame it. :-)
First off, your hone should indeed be absolutely flat. If not, you need to look up Josh Earl's tutorial thread for lapping hones, and get it properly lapped.
Here's your new improved slurry raising recipe for callous coticules: fold a piece of 220 grit (other grits might work too) sandpaper around a small wooden block. Use that sanding pad on a dry coticule (that's right, no water, not just yet). Sand the entire surface till it is covered with fine coticule dust. It won't take very long. At this point, add a few drops of water, and use your cotigura stone to mix the dust with the water to a rich slurry. Add more drops of water and smear till you're happy with the consistency. With this slurry you should be able to remove metal and witness how it darkens to a rich gray, within 30 to 50 honing laps.
Should your stone be the latter case (slow garnets), than, no matter how nice a slurry you raise, it might take hundreds of laps before you start noticing the presence of metal particles in the slurry. While such stones might very well be even finer polishers, you won't be able to cut a good bevel with them. In that case, it might be better to use it only for finishing the edge and do the preceding honing part with another hone such as the DMT1200 or the Norton 4K before you jump to your lazy coticule with slurry and finish with only water.
BUT... you can also cheat that coticule into thinking it is a fast cutter. :-)
Get yourself a lightning fast and soft cotigura stone (cotigura = the little piece of coticule that you use to raise the slurry). Throw away that sandpaper and rub with your cotigura on your coticule till you have the slurry of your dreams. 80% or more of that slurry will be produced by that cotigura, but who cares. Your razor doesn't.
If you're interested in such a superior cotigura stone, PM me about it.
Hope this helps,
Bart.

Assessing a honing job is a matter of eliminating a number of variables. First, is your coticule flat? If it's not, that's the first variable to eliminate. Second, are you using magnification so you can see the edge before treatment and then after treatment? That's the sure way to know what you're doing and what effect you're having on the edge. The coticules do come in 2 grades from the quarry in Belgium. The euro grade and the Select grade. I only sell the Select grade and they're pretty uniform! There is always variation in natural stones but the difference in final shave is more likely to be from other factors. Keep at it. For hundreds of years barbers used a coticule and a natural leather strop and you're likely to get good results if you can see exactly what you're doing. The HHT is a very subjective test and many have come to the conclusion that the only real test of an edge is whether or not it shaves your face.

Thanks for the input gents!

First, I will collect the material necessary to lap the coticule as described by Josh Earl... once that job is done, I will give the honing another try... actually, my coticule looks like it is flat, but that might not be the case.

@Bart: I will keep you posted on the progression and maybe I do need another cotigura... my rubbing stone is quite large (about 1.5cm by 5cm), is it possible I do not put enough pressure on it to generate thicker slurry? Anyway, I will put a picture of the coticule online as soon as I have the time to take some pictures :)

@Howard: I bought my coticule here in a shop in Belgium and I have no idea what quality grading it got.

Best regards!

There's only one coticule quarry left, and each new coticule that's sold comes out of that quarry. They have a website: Ardennes Coticule - pierres à aiguiser et moellons de Vielsalm Belgique.
They actually produce coticules in four different grades: third grade (mainly sold for industrial use), standard grade, select grade and kosher (very rare). The first three are basicly all the same stones, with more, or less cosmetical flaws. Absolutely flawless and uniform in color is sold as "Kosher". The current grading system has nothing to do with the hone's capabilities, but I don't think that Maurice and Rob Celis allow coticules with serious defects to leave their firm.
I only noticed a minute ago that you're a fellow countryman, Tim.
What's you location? I'm from Heist-op-den-Berg. Together with two other straight shaving guys we're having a cozy shaving night every 6 weeks or so. We send off the wifes to the pub and hone razors, smoke cigars, and drink whisky while talking about genuine guys stuff. You 'd be more than welcome to bring your coticule and razors.:)

Good luck,
Bart.

Hi Bart,

We 're fellow countrymen, indeed! I'm living in Dendermonde, so that's not too far away from Heist-op-den-berg! It'd be great to attend one of the shaving nights and get to know other straight razor shavers... I don't smoke cigars, but wouldn't say no to a glass of whisky :)

BTW, at present I don't feel like I've received a bad coticule or so... Probably it's just me who's doing something wrong... Tomorrow, I'll fetch the sanding paper and give the lapping a try. I started this thread to find out if it's possible to see the difference between a "good" and "bad" coticule in some way, for example through a microscope or so... As the honing results are not there yet, I might eventually feel the urge to buy a "kosher" coticule though... it's starting to itch :)

Thanks for the invitation! ;)

Tim

Hi all and especially to Bart.
I read often that a str8 razor is getting sharp when it start to "undercut" the slurry instead of pushing the slurry forth with the bevel.
Is this real a sign of sharpness, or is it only some kind of urban legend?
My coticule never undercuts the slurry, but I do get excellent bevels.

Best regards

Quote:

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Originally Posted by kingreverent

Hi all and especially to Bart.
I read often that a str8 razor is getting sharp when it start to "undercut" the slurry instead of pushing the slurry forth with the bevel.
Is this real a sign of sharpness, or is it only some kind of urban legend?
My coticule never undercuts the slurry, but I do get excellent bevels.

Best regards

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As a matter of fact, I always pay a lot of attention to what the fluid on the hone does during the passage of the razor. In my opinion, that's all part of what is often called "feedback" of a particular hone: all things that can be felt, heard or seen while honing.

Whether water or slurry runs up the razor, depends on a few variables, and I wouldn't consider water or slurry running up the razor a sign of keenness, but it does tell me certain things about my stroke. For instance: if you hone a smiling edge, and you don't do anything specific to improve contact with the heel and toe of the razor, the result will be a razor with a sharp middle part and a dull toe and heel. For tackling that problem the "rolling X-stroke" allows for better contact with the hone along the entire edge. But how much "rolling" does one needs to apply to his stroke? The answer is: watch the water (or slurry) run up the blade. Set your mind at making the water run up the heel section first, then up the middle section, and finally at the end of the stroke, up the toe. Focus on that, watch the water (slurry) and your arm will make it happen almost automatically.

The same thing works equally with slightly warped razors. Watch the fluid and it 'll tell you where and how to fumble with your stroke to maintain contact with all parts of such a blade.

As for sharpness: if you take a blade with a serious roundness to its bevel, such as many old razors coming from Ebay or an edge stropped to oblivion by ignorant hands, that blade will tend to push a wave of fluid in front of the edge without it running up the bevel. That effect is most apparent when the layer of fluid is thin and the blade is still dry. As soon as the blade becomes wet, the water will run up more easily, due to cohesive forces in the water molecules. But if you observe real close how the water searches the easiest way to run up the bevel you 'll now where that bevel is starting to develop and which part is staying behind. I'm not saying that I'm relying on that alone, while honing, but it does often tell me when not to bother with a TPT just yet, but keep on going a bit further.

On a coticule with slurry, I have witnessed many times how the slurry runs up the bevel very well during the first few laps and then starts to be more pushed in front. That's because the use of slurry on a coticule has some abrasive effect on the bevel tip of the edge. The garnets are removing metal from the sides of the bevel quickly, but they also meet with the tip. That's why you always should finish on a coticule with water only. That way the garnets stay embedded in the surface and while the coticule cut much slower in that fashion, the abrasive effect on the bevel tip is prohibited. I generally hone during my finishing stage on the coticule with water till I see a clear improvement of the water running up the bevel again. Then I perform a final TPT, and if everything checks out, I move to the strop and test shave.

As to razors "undercutting" the slurry, I think it depends a bit on your definiton of that verb. Sure, an edge will always push a fluid forth, but an amount of it will run up that bevel, and there is some relation between the width of the tip and the amount of fluid running up. Learning how to read that, takes experience, and I believe you could easily do without that skill, if you chose to. Some people have stated they can feel it in the way a razor rides the hone, when it is sharp. I personally am not blessed with such "fingerspitzengefuhl", as the Germans say, but what works for someone might not work for another, and vice versa.

I hope this answers your question,

Regards,

Bart.

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Originally Posted by Tim

Hi Bart,

We 're fellow countrymen, indeed! I'm living in Dendermonde, so that's not too far away from Heist-op-den-berg! It'd be great to attend one of the shaving nights and get to know other straight razor shavers... I don't smoke cigars, but wouldn't say no to a glass of whisky :)

BTW, at present I don't feel like I've received a bad coticule or so... Probably it's just me who's doing something wrong... Tomorrow, I'll fetch the sanding paper and give the lapping a try. I started this thread to find out if it's possible to see the difference between a "good" and "bad" coticule in some way, for example through a microscope or so... As the honing results are not there yet, I might eventually feel the urge to buy a "kosher" coticule though... it's starting to itch :)

Thanks for the invitation! ;)

Tim

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As far as I'm aware of, quality differences between coticules are not readily to be seen under a microscope. I'll keep you posted when our next shaving night is due. You can bring your coticule, and be able to compare it's honing behavior with more other coticules than you ever wanted. :)
Cigar smoking is recommended, but not required. :D

Hartelijke groeten,

Bart.

Tim,
If you bought the coticule in Belgium, you may have gotten the euro grade of stone. I heard from one SRP member that they carry that grade in the shaving shop in Antwerp. I mailed him a Select grade coticule (how about THAT! shipping coticules BACK to Belgium! Strange but true) and he sent me an exclamatory email praising the stone. The slurry you describe as the consistency of milk is exactly what you should be using to hone your razor. The Belgians call it an "abrasive milk". If it gets too thick, just spritz some water on it to make it more milky.

As planned, this weekend I collected sanding paper (320 and 800 grit) and flattened the coticule (for the first time)... Thanks to the hone lapping 101 this was an effortless job! After lapping, the difference was clearly noticable on the hone...

So far for the good news... I started with a "milky" slurry (I cannot produce thicker slurry) and gradually added more water to end up with only water after about 70 laps... Then I did about 15 laps on the coticule with water only to finish on the strop... result: I (further) dulled my TI's edge :cry:
Only after 30-40 extra laps on the coticule with water the razor started to split (note: NOT pop) hairs again when trying the HHT... but the shave still felt rough :( I really don't know what's going wrong, I really try to minimize pressure to the absolute minimum on every (X pattern) stroke... sigh
On the positive side, the razor splitted hairs over the entire edge now, probably due to the flattened hone... I did not mention it before, but it originally only splitted hairs at the toe and the tip...

@Howard: yes, I bought my stone in Antwerp about 2 years ago, maybe there was no grading system at that time, I don't know... until recently, the TI was my only razor and I was afraid to ruin it while honing, that's why it took so long for me to really start honing. In the meantime, I went back to the shop to get it honed (coticule + pasted strop) and bought the Dovo from Lynn... Conclusion: 2+ years of shaving and stropping experience, but little experience in honing.

Tim

Tim: keeping pressure to a minimum is good at the end of a honing cycle but in the beginning, you want to have a little pressure on it--as Howard will tell you, you are grinding steel. You need some pressure. Towards the end, lightening up is a good idea. Another feedback cue to watch for on Belgians: when the edge is getting close, you will start to feel a kind of "pulling" or "skipping", almost as if the blade is trying to cut into the stone but can't. Right about then is when I start to back off on pressure. Also, just to echo what others have said, don't worry about overhoning; you won't create a wire edge on a Belgian. The only thing you'll do is remove more metal than necessary--the edge will reach a certain sharpness level and stay there.

Also, did you already have a sharp bevel (Good TPT) before you started on the coticule? It could take a while to hone up (several hundred strokes--remember, you won't overhone;)-- if you didn't. If your razor has a double bevel to remove, you're going to need a coarser stone first.

Let us know how it goes.

If they honed it in Antwerp (coticule with slurry, and after that a pasted strop with red Dovo paste), that razor will have a bit of a convex bevel. That's not a bad thing as such, but since you are honing on a coticule only, you need to get rid of that convex bevel first, before you can gain any real sharpness.
This would be easier if you could do a few laps on a coarser hone (like a DMT 1200 grit), but since you can't, you 'll have to do enough work on the coticule. I agree with PA23-250 about the pressure. Doing circling back and forth honing motions at the same time, speeds the process up even more.
Is that slurry turning grey yet? It needs to turn gray before you have removed any significant amount of steel. When polishing, it does not have to become gray.
On the other hand, the splitting hair thing suggests that you are nearly there, unless you're a skilled stropper. In that case you might have stropped a bit of an edge to that convex bevel. Think about this: as long as you haven't successfully removed the jaws of that convex bevel, the tip of that bevel is not touching your hone. It makes no sense polishing anything on the coticule with water, if you haven't created an already very sharp edge during the slurry stage. To complicate things even further, slurry on a coticule will max out the edge at a certain level, that's just below what I consider to be shaveready. If you set the bevel of your razor on a coticule with slurry, than you need to still improve taht bevel to some extent during the polishing stage with water only. That might take many laps, certainly more than 15. Gradually diluting the slurry helps a bit, but still.

Don't give up. I'm sure you'll get there eventually.

Bart.

The key element in your post was that you have been using the TI for about 2 years without going to a hone for a "refreshing" of the edge.

I would agree that your bevel may have been slightly convex from the initial honing and the edge further rounded from 2 years of daily shaving and stropping. Since your edge is now snagging and splitting the hair for the length of the blade it sounds like your honing stroke is good. With an enormous amount of persistence and patience you could get the bevel set and the edge sharp with the stone that you have. One of our members in The Netherlands, Theo, has done it but it took thousands of laps, literally. My suggestion is to meet with the others in your country and have one of them reset the bevel for you with a proper stone or use some 1000-2000 grit sandpaper. The 2000 grit is roughly equivalent to a 4000 Norton ( different measuring system standards).

Just my two cents,:)

Quote:

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Originally Posted by Bart

Absolutely flawless and uniform in color is sold as "Kosher".
Bart.

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FWIW, Rob Celis also told me that in addition to the two criteria you mention qualifying a coticule as "Kosjer/Kosher", the bonding where the yellow coticule and slate substrate meet must be perfectly even. No variation in thickness as seen from the sides or ends of the stone or slate is allowed.

IF Kosher stones are even a remote possibility of being available to you, then Rob must be selling those only to Belgians! Rob told me the Ardennes mine only offers up to the select grade and does not offer Kosher stones. That was last year, so maybe if one begs and pays whatever price must be paid to get one, there are Kosher coticules avaible to the public?

Chris L

Actually, the feedback I get from the honing process is quite confusing :thinking:: slurry does not turn gray, but it does feel like the razor is cutting in the stone at the end, when only water is used. Also, as you mentioned, the fact that the razor is--eventually--splitting hairs (before stropping) indicates that actually something is happening to the edge.

@Randy: During this 2-year period, I used the TI for about 1.5 years with regular (every 4 months or so) touch-ups in the shop in Antwerp (coticule with slurry + strop with red Dovo paste). After that, I got the Dovo from Lynn and used that for a couple of months. Now, both razors need to be honed and I'd like to do it myself. BTW, compared to the Dovo, the TI has never had that sharpness.

Tim

Quote:

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Originally Posted by Chrisl

FWIW, Rob Celis also told me that in addition to the two criteria you mention qualifying a coticule as "Kosjer/Kosher", the bonding where the yellow coticule and slate substrate meet must be perfectly even. No variation in thickness as seen from the sides or ends of the stone or slate is allowed.

IF Kosher stones are even a remote possibility of being available to you, then Rob must be selling those only to Belgians! Rob told me the Ardennes mine only offers up to the select grade and does not offer Kosher stones. That was last year, so maybe if one begs and pays whatever price must be paid to get one, there are Kosher coticules avaible to the public?

Chris L

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Ardennes Coticule - natural sharpening stones from Vielsalm Belgium. - Online shop

:)Cheers,

Bart

Bart... thanks so much! I just ordered a kosher coticule. Now I can compare that to my vintage coticules especially the Deep Rock and the Old Rock coticules. I will finally have an answer as to the quality of the "kosher" stones.

Thanks again!:tu

Quote:

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Originally Posted by Tim

Actually, the feedback I get from the honing process is quite confusing :thinking:: slurry does not turn gray, but it does feel like the razor is cutting in the stone at the end, when only water is used. Also, as you mentioned, the fact that the razor is--eventually--splitting hairs (before stropping) indicates that actually something is happening to the edge.

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I don't know about the razor "feeling like it tries to cut the stone", since I have never observed that feeling myself, but your statement that the razor starts to split hairs BEFORE stropping is very good news. It really means that your bevel is starting to be truly sharp. I would not do any more slurry honing from this point onwards. Use only water and do light laps, and you'll gain sharpness with each lap. (use slurry and you'll loose the splitting hair ability again!)
Test at about every 30 laps. I really recommend the TPT for that kind of keenness assessment. Try adding a drop of dish washing detergent to the water. Don't know if it improves the outcome, but I always do, and my coticules deliver fine edges. Some guys have reported finer edges with the use of lather. I haven't tried it though, but it wouldn't harm to try.
I wouldn't worry about removing too much metal on a coticule with only water, it might be possible that you still need to do 100 laps more.
I also emphasize strongly on a good stropping session after honing.

Although your TI should be able to be brought to more than shavereadiness with that coticule, I wouldn't expect to match Lynn's results. He's out of our league, whatever that means, and I would think he uses finishing methods beyond the grasp of your coticule. If you want a cheap way to push the sharpness envelope after a coticule, than a strop with Chromium oxide is the way to go. I have more Chromium oxide sitting on the shelf here than I'll ever use in this lifetime or even that of my offspring. If you PM me your address, I 'll send you some of it. It's no good though, using it before that razor is absolutely shaveready right of that coticule.

Good luck,
Bart.

Quote:

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Originally Posted by Tim

@Randy: During this 2-year period, I used the TI for about 1.5 years with regular (every 4 months or so) touch-ups in the shop in Antwerp (coticule with slurry + strop with red Dovo paste). After that, I got the Dovo from Lynn and used that for a couple of months. Now, both razors need to be honed and I'd like to do it myself. BTW, compared to the Dovo, the TI has never had that sharpness.

Tim

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I hope they used the Dovo red paste before they used the coticule. The red is coarser. Also, the TI takes a bit more work than the Dovo but it can be every bit as sharp.

Vintage coticules are usually fine enough. If you turn to new coticules: they come in 3 grades: the kosher quality being the best. The other 2 qualities are called differently by different vendors, IIRC they are called something like extra and extra extra. After the kosher quality coticule I don't think you need a CrO2 pasted strop.

Quote:

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Originally Posted by Tim

Hi everyone,

I am trying to touch up the edges of two razors on a coticule. The first is a Dovo I got from Lynn a couple of months ago (was a perfect shaver upon arrival) and the second is a TI I bought new about 3 years ago. Now that I have felt what shave-ready feels like (the Dovo), I can confidently say that the TI has never been that sharp.
After considerable work on the coticule (30-50 laps with and without slurry), both razors pass the marker test and "almost" pass the HHT: hairs split but do not pop... and the shave test felt rough :eek:
Because this is my only hone, I cannot tell whether the poor honing job is caused by the hone, my technique, or both... Therefore, is there any way to assess the quality of a coticule, next to the honing result? I have read somewhere on this forum that the quality of natural hones can vary... As all coticules look more or less the same, I suppose it does not make sense to put a picture of my stone online... wait, there is a small grey-black spot (about 0.5" by 0.25") on the (yellow) honing surface :hmmm:

Any ideas?

Thanks in advance for your assistance!

Best regards,

Tim

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I bought my kosher coticule from Rob Celis when I visited the quarry. But there's definitely variation in thickness of the coticule and unevenness where coticuel and slate meet. IIRC kosher refers to fineness and evennes of the grit rather than macroscopic appearance.

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Originally Posted by Chrisl

FWIW, Rob Celis also told me that in addition to the two criteria you mention qualifying a coticule as "Kosjer/Kosher", the bonding where the yellow coticule and slate substrate meet must be perfectly even. No variation in thickness as seen from the sides or ends of the stone or slate is allowed.

IF Kosher stones are even a remote possibility of being available to you, then Rob must be selling those only to Belgians! Rob told me the Ardennes mine only offers up to the select grade and does not offer Kosher stones. That was last year, so maybe if one begs and pays whatever price must be paid to get one, there are Kosher coticules avaible to the public?

Chris L

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