cutting speed

[pinklather]

For a jnat, a test of cutting speed is 20 regular x-strokes on water only. Does it darken the water? if so, it's fast, if not, how many strokes does it take?

I notice that the speed on water goes up to only moderate - which seems to indicate very few are fast on water. Is there a way to gage this speed? 20, 30, 50 laps on water before the water detectably darkens from slurry?

Many Thanks in advance.

I sent a msg to Maurice, asking for attributes first, then size. Hard, fine, fast, then, preferably a full size rock. As Bart mentioned in one of the threads or the trip report to Ardennes, selling by attribute would be a big plus. Jnats seem to be done that way.

 

[danjared]

Maurice barely has enough time as it is. He can identify the vein of a stone very well, but I seriously doubt he will have time to get back to you with such specific details.

 

[Bart]

I too doubt he will provide a thorough answer. Coticules are no Japanese hones. If I understand the Japanese situation, their natural hones come form a variety of locations and rocks, providing many different whetstones with different properties. With Coticules, we're dealing over a relatively small mining area (all mines were located in an area of about 10 X 10 km). It's one very particular type of rock. The differences are far less then those of Japanese stones.

When it comes to speed, almost all Coticules are very slow when used with only water on top. In the Coticule Vault, my speed estimations about speed on water do not relate to my speed estimations when used with slurry, "moderate" on water is still much slower than "moderate" on slurry. Furthermore, there are Coticules that among the fastest on slurry and among the slowest on water, and vice versa. I've never been able to conclude anything based on variances of hardness of the rock. The majority of Coticules are roughly the same hardness anyway, but I've tested soft ones that were among the slowest (on slurry) and soft ones that were among the fastest. The same can be said for Coticules that seems harder than average
When it comes to end results, the differences are practically nonexistent. Let's say 7 Coticules owners were to send me their specimen, and I would hone the razors of a 7-day set on each one of those. I am certain that no one of the owners would recognize his own Coticule upon test shaving with all 7 razors. The edges would just be too closely the same. The only difference would be that I would not do an equal amount of strokes on each stone. The longest stone would probably need the smallest amount of strokes.

Kind regards,
Bart.

 

[james]

When it comes to end results, the differences are practically nonexistent. [...] The edges would just be too closely the same.

Sorry for the OT people, but...
Bart, would say this is true even for vintage coticules from other mines?

 

[geruchtemoaker]

When it comes to end results, the differences are practically nonexistent. [...] The edges would just be too closely the same.

Sorry for the OT people, but...
Bart, would say this is true even for vintage coticules from other mines?

as far as I know it is and bart's speaking coticules in general including "vintage" ones

regards
Stijn

 

[pinklather]

Bart, Thank you for your kind response.

It makes sense that the speed for slurry vs water is dramatically different. You've said that the final result (assuming proper use) produces very little difference between stones.

It also makes sense that the longer the stone, the fewer the strokes.

The part that I'm trying to get perspective on is quantifying that difference in the number of strokes on a slow vs moderate speed cutter on water. If a moderate stone took 50-75 strokes to finish on water (arbitrary guess), would a slow stone take 200? 400? (bringing it into the speed class of a translucent arkansas stone used w/ oil)?

The question I can't yet wade into is how, if there is so little discernable difference between net results, can we have so much to say about their differences? That's too big a question to tackle for me, so the question of speed becomes more important.

Again, I appreciate your kind help.

 

[Bart]

When it comes to end results, the differences are practically nonexistent. [...] The edges would just be too closely the same.

Sorry for the OT people, but...
Bart, would say this is true even for vintage coticules from other mines?

As far as my experience with vintage Coticules extends, the answer is yes.

If a moderate stone took 50-75 strokes to finish on water (arbitrary guess), would a slow stone take 200? 400? (bringing it into the speed class of a translucent arkansas stone used w/ oil)?

No. All Coticules are garnet based. You may ask yourself: "What has that got to do with it?" Coticules are generally used with an abrasive slurry, that contains these garnets. This speeds up the process. The slurry needs to be diluted as you go along. By the tile you arrive at water on limited work on plain water is required to get the maximum of the Coticule. The challenging part is to practice a very even and stable honing stroke, and cover the entire edge as you go along. A razors edge has an extremely delicate keenness, that can be disturbed with the slightest user error.

The question I can't yet wade into is how, if there is so little discernable difference between net results, can we have so much to say about their differences?

Because we're humans. We like to think the tool is responsible, when there is a lack of results. There are several members on this forum tha t have mastered the use of Coticules. It takes time to reach that level of competence, just like it takes time to become a proficient straight razor user. There will always be people who think they don't have the right Coticule when it they can't immediately obtain the excellent results they read about. Razor sharpening has the disadvantage that it appears very easy at first sight. Laying a razor on a flat surface and rubbing it over it, that can only be a piece of cake, right? When I started sharpening my own razors, I was already sharpening plane blades and chisels for nearly 20 years. I took me 3 months of misery to swallow my pride and ask for help.
Due to that denial and tool blaming, the idea is present on most forums, that differences between end results off Coticules are very significant. Oposing that idea is like mopping with an open tap (a saying in Belgium)

Kind regards,
Bart.

 

[pinklather]

Thank You Again, Bart.

Your words about wanting to blame the tool are VERY well received, and I couldn't agree more. Having no particular native talent at honing, I must make up for that deficit by endless practice. At this point, I've honed about 65 blades to shaving sharpness - with varying degrees of success/quality. I suspect I need another 10x that many to feel I have any real proficiency. At least it's fun! I suspect very few questions would remain if I had a few hundred blades experience on the coti.

I understand that the norm for coticule honing is to either take the blade from either a set bevel or full dullness and bring it through the stages of keenness by slurry and successive dilution. I know that's totally different from most other stones in how that must be managed. My intent, initially, will be to use the coti towards the end of a progressive method - likely coming from either an 8k Naniwa, or a Chinese 12k. Before the asagi, it must have the 12k readiness. Many like to use the Japanese stone in a 'one stone' approach also, but this is not my intent. The primary task - at least at first, will be just finishing, after reaching shaving sharpness from the 8 and 12k. Unless I'm missing something (quite possible/probable), the speed of honing from there will be determined by the stone's cutting speed on water alone (assuming I do my part adequately). I can imagine first coming from the 12k, and then beginning slurry manipulation to try going from the 8k, but initially, it will be from a 12k.

If it helps, I know that a stroke count for the difference between fast and slow would be relative/approximate. That approximate sense is what I'm trying to learn. Slow is 3x? 5x? 15x the number of stroke for a 'moderate' stone on water?

 

[Bart]

If it helps, I know that a stroke count for the difference between fast and slow would be relative/approximate. That approximate sense is what I'm trying to learn. Slow is 3x? 5x? 15x the number of stroke for a 'moderate' stone on water?

Now I understand your question. But I don't know the answer. It's been years since I finished with a Coticule after a another hone. My best advice is to start with 30 X-strokes on pure water. Make sure that your edge is flawless off the preceding hone, before you do this.
Evaluate the shave and take it from there. You could add another 50 before the next shave, to see if this makes a further change for the better. One of the advantages of a Coticule is, that once the edge has maxes out on water, you can do 1000 laps and more without any other adverse effects than wasting time and a tiny bit of steel. Soon you'll get to know your Coticule and know how many laps to perform. Do note however that the width of the bevel has a huge influence. Wide bevels require considerably more work than small ones.

Should the Coticule with water only not provide the expected results, the most likely cause is that the edge lacks a bit of keenness. Unlike some synthetic hones, a Coticule leaves a very smooth edge. To perform well, it needs to rely on ample keenness. In that case, you should try to rub the hone two or three times with a slurry stone after moistening it with water. Give the razor a work-out on that, and refinish as explained above.

But at the end of it all, I can't give you a recipe that substitutes the need to become properly acquainted with your Coticule. Luckily, that is part of all the fun.

Kind regards,
Bart.

 

[kessel113]

But at the end of it all, I can't give you a recipe that substitutes the need to become properly acquainted with your Coticule. Luckily, that is part of all the fun.

Kind regards,
Bart.

It's like cooking... theres not a time table or a definite time to know wen your steak is ready.
It all depends on so many variable... like the thickness of the steak,the stove electric or gas, even 2 gas stoves will not give you the same temperature at maximum settings.

practice and experimenting are what will give ourselves the ability to achieve what we are looking for.

 

[pinklather]

Bart, Thank You again.

I feel somewhat badly that I couldn't have made the question easier. I don't mean to frustrate your kind help.

Starting w/ 30 and trying a shave makes sense. I'm used to looking for metal swarf (darkening of water) from the process, but first 30, then 50 more gives some idea of how to find the edges of stone speed. I'm guessing (rightly or wrongly), that a stone that finished adequately well at 30 strokes would be a 'moderate' speed on water.

I'm grateful for your patience. I don't take it lightly.

All best

 

[Bart]

It's like cooking... theres not a time table or a definite time to know wen your steak is ready.
It all depends on so many variable... like the thickness of the steak,the stove electric or gas, even 2 gas stoves will not give you the same temperature at maximum settings.

That is a very good comparison. :thumbup:

Kind regards,
Bart.