The problem with coticules

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I started this thread in the hopes that forum members could tell me all the bad things about coticules. The problem is that I have formed an inflated grandiose narrative about them that needs debunking. It goes like this:

The coticule is the perfect stone. It is creamy and fun to sharpen on, surprisingly fast, and you can pretty much pick your effective grit, just by choosing how much slurry to work with. You could bring one stone on a trip, and use it to sharpen knives to toothy lethality with slurry, and hone your razor with just water. Newbies should just skip the synthetics and JNats, and buy one coticule for all purposes.

I know this cannot be true. I know that it's just the result of my getting really excited about coticules, and discovering their possibilities. So, bring on the doom and gloom: what are the downsides of coticules?
 
I started this thread in the hopes that forum members could tell me all the bad things about coticules. The problem is that I have formed an inflated grandiose narrative about them that needs debunking. It goes like this:

The coticule is the perfect stone. It is creamy and fun to sharpen on, surprisingly fast, and you can pretty much pick your effective grit, just by choosing how much slurry to work with. You could bring one stone on a trip, and use it to sharpen knives to toothy lethality with slurry, and hone your razor with just water. Newbies should just skip the synthetics and JNats, and buy one coticule for all purposes.

I know this cannot be true. I know that it's just the result of my getting really excited about coticules, and discovering their possibilities. So, bring on the doom and gloom: what are the downsides of coticules?
Not expensive enough, so you kinda need to buy em all
 
There's variation within the layers, so the one you end up with might be slower and finer than you would like for a kitchen knife. Iif you don't really care about heading down the polishing hole, pretty hard to argue that a BBW/Coti combo won't do pretty much everything for you once you get above say, a SG500. The big one I have is the leading candidate to be the "in the kitchen" stone, and I've got a hard time believing any other single stone is going to move ahead of it.
 
i've used cotis for many years with my straight razors, and I like the versatility of them. Ising the dilucot method I can pretty much use one stone, from setting the bevel to finishing (depending on the razor).

Individual stones and veins do vary a fair bit, so it pays to have a clear purpose in mind when selecting the stone.
 
I have this one which I’ve been meaning to try with a knife. I was not blown away by it with razors, but I think it will be an excellent knife stone. Judging by how dished in the middle it was when I got it, that was what it was originally used for.

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I have this one which I’ve been meaning to try with a knife. I was not blown away by it with razors, but I think it will be an excellent knife stone. Judging by how dished in the middle it was when I got it, that was what it was originally used for.

View attachment 195865View attachment 195866


That’s gorgeous D. I woulda given you very good money for that useless old razor hone! ;)
 
I started this thread in the hopes that forum members could tell me all the bad things about coticules. The problem is that I have formed an inflated grandiose narrative about them that needs debunking. It goes like this:

The coticule is the perfect stone. It is creamy and fun to sharpen on, surprisingly fast, and you can pretty much pick your effective grit, just by choosing how much slurry to work with. You could bring one stone on a trip, and use it to sharpen knives to toothy lethality with slurry, and hone your razor with just water. Newbies should just skip the synthetics and JNats, and buy one coticule for all purposes.

I know this cannot be true. I know that it's just the result of my getting really excited about coticules, and discovering their possibilities. So, bring on the doom and gloom: what are the downsides of coticules?


I’m afraid to say I think your constructed narrative is pretty much on the money. A coti x bbw combi might as well have been tailor made for Japanese kitchen knives imo. I’ve never had a jnat edge I like as much as a good coti edge, and Belgian Blue even polishes brilliantly.

If you were to pick one shortcoming it’d be what people have mentioned above:

There's variation within the layers, so the one you end up with might be slower and finer than you would like for a kitchen knife.

When the yellow side is very hard and fine they become less useful for knives / more difficult to freehand on. From what I’ve had I’d say maybe 25% I’ve not liked much for knives, 75% are golden.

However... in terms purely of knife sharpening and repair work (ignoring razors) this is also still true:

For knives, 1 natural stone for the road, I'd say washita probably.

Old Washitas have the most extraordinary range. Turkish come close, but really nothing is quite as impressive as a good Washita.
 
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I just won another very cheap one on ebay. You couldn’t really tell how thick it is, but it’s not too dished, a big surface area, and I was the only bidder :)

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UK Ebay is lousy with screaming deals on these, if only their intl shipping wasn't preposterous...


Oh dear you’re gonna hate me for this... 😬

Just after my reply above I had a few hours to kill in Bristol and went to a small second hand tool shop a friend told me about. Was a complete treasure trove! Came away with a few nice things, best of them being an immaculate 8x2 Norton green label translucent, and a gorgeous 7.25 x 2 coti. Haven’t lapped yet, but here they are after a bit of a cleanup:

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That stone turned out to be an absolute gem :).

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And a perfect example of this:

and use it to sharpen knives to toothy lethality with slurry, and hone your razor with just water.


Used just with water - the shave here was fantastic. The best coti edge I've got to date.

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It's a fine stone, but with slurry raised the stone is fast enough for kitchen knife use, and swarfs up a fair bit after just a couple of strokes. Giving an edge that will slice toilet paper while still retaining a nice degree of toothiness to the finish... something which can only really be done on very good, fast and fine coticules ime.

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I started this thread in the hopes that forum members could tell me all the bad things about coticules. The problem is that I have formed an inflated grandiose narrative about them that needs debunking. It goes like this:

The coticule is the perfect stone. It is creamy and fun to sharpen on, surprisingly fast, and you can pretty much pick your effective grit, just by choosing how much slurry to work with. You could bring one stone on a trip, and use it to sharpen knives to toothy lethality with slurry, and hone your razor with just water. Newbies should just skip the synthetics and JNats, and buy one coticule for all purposes.

I know this cannot be true. I know that it's just the result of my getting really excited about coticules, and discovering their possibilities. So, bring on the doom and gloom: what are the downsides of coticules?
I prefer harder stones that don't self slurry, it's just easier for me to get cleaner apex's. Also for many tasks I prefer a toothier edge than coticules deliver. Coti's will also dish more than some of the other naturals.

Now don't y'all flame me crispy, he only ask about the negative.
 
Don't own any cuticules, but I never see them used for polishing blades, so I'm guessing they're nothing special when it comes to that.

I could be completely wrong, and people just don't talk about it, or haven't tried it.
 
You're looking for an argument against Coticules? Fine... There's no one Coticule that fits every job. Your argument about them having a fairly large cutting range on slurry, and being able to tackle a variety of steels is typically sound, but there's nuance about these stones that sort of tears apart the 'ultimate stone' argument.

It's easiest to see, if I just describe a couple of the stones I have...

I've got a super-hard La Verte, that probably peaks somewhere around 15K on plain water, and on a thick slurry can erase 600-grit scratches. It's a beast. At the same time, every time I sharpen a razor on it, I end up looking like Edward Scissor Hands. When I sharpen kitchen knives on it, I end up with a smoother edge than I like unless it's for something I'm slicing fish with it, or a sharpening a garnish-parer. EDC, again, it's lacking tooth... The thing's perfect on woodworking tools. Never seen a better, longer-lasting chisel or plane-blade edge on O1 or A2 than off of this stone.

I've got a particularly crazy La Dressante sample, out of several... Maybe peaks out at 8K-ish, and can lift from a Shapton Glass 500 on a dense slurry. The thing cuts high-carbide steels like crazy even on plain water (It'll eat HAP-40/CPM-M4! Not as keen as diamond, but it'll cut it faster than a 4K Shapton Glass HR stone on plain water, and leave a better edge.), and wears very little. It'll tear up a razor; it's like shaving with a hacksaw blade. At the same time, it's a great edge on certain steels for cullinary work. Major tooth, yet super keen. Not all La Dressante's behave this way. This is just how this one copy seems to behave.

I've got a couple La Gris; the common ones... One's just a total dud. Leaves deep random scratches, is slow, leaves a smooth edge in maybe the 6-8k range that's sort of good for nothing, is soft/wears fast, etc... Bad stone. The others aren't that bad, but lack a little something.

I've got a Les Latneuses, that creates one of my favorite straight-razor edges. Smooth, yet super sharp. It's a fast cutter with a high abrasive volume, but very fine and consistent particle size. Sucks on kitchen knives and most EDC, as it lacks some tooth, and wears a bit fast for woodworking tools, but for certain straight razors it's just amazing. There's a lot of variability amongst different Les Lat's.

Some Coti's can lift from like a 500-600 grit stone, and others struggle to start from a 2-3K stone on a thick slurry. Some create good edges for razors, others for woodworking tools (I've sharpened carving axes and knives, and chisels and plane blades on them.) , and others for cullinary knives, or 'Gentleman Carry' style EDC.

Sometimes other natural stones, like Arkansas or J-Nats will deliver a better edge on certain steels. Sometimes, a synthetic stone, diamond plate, a pasted strop, etc, will delivery the most amazing edge you've ever felt on that blade.

The key downside to Coti's, is simply the variability you get with any sharpening stone; particularly natural ones... There's no 'Swiss Army Knife' stone, for every steel/tool, as it's easy to imagine that Coti's are.

If you had a specific tool, that fit a specific Coti, you could conceivably maintain it on just that stone. Good Coti's do have a remarkable range. As you can probably see, though, no single Coticule is universal. Each sample is pretty unique.

Hope this helps...
 
Eh good point.

I will say. Good luck sharpening 10v, maxamet, or rex 121 on a coticule. It might cut it, but I doubt it will work efficiently at all. I certainly would rather have another stone for one of those steels. Or any of the steels that have a higher vanadium carbide volume than something like m4.
 
They're soft and fragile as well. But pretty dang versatile. Can't add much to what's already been said.

I haven't experienced as much tooth as some others have, but not sure if it's stone variation, lack of skill, Mercury in retrograde...
 
I think using them as a one stone solution is a bit of a waste of good stone. Unless it's a one and done travel stone. Fun skill to have but for god sake wear out the synthetics first
They do wear so fast using them for knives and chisels. I have had several. I kept two that I use for razors. One mid range and one finisher. I don't touch them with anything but razors to prolong their life.
 

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