Thread: Assess coticule quality?

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,

Originally Posted by Bart

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

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 : 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

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

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!

Originally Posted by Tim

Actually, the feedback I get from the honing process is quite confusing : 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.

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.

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

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.

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
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

Any ideas?

Thanks in advance for your assistance!

Best regards,

Tim

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.

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