Thread: Can't fugure out why my coti don't work

I have a nice old coticule stone that is about 1 1/2 X 8. I lapped it and aside from some hairline cracks from age it is a nice stone. However, no matter what I try I can't get it to put an edge on my razors. I have owned and sharpened about 50 razors over the last 30 years or so, using various stones and means. Using the coticule though, no matter what I try, and I have tried the unicot and dulucot methods, and just water and end up with a razor that is not sharp. Every time I try I end up finishing it on a different hone. It just don't work for me. I hate to do it but I think I am going to use oil on it and try that. I don't know what else to do. Any suggestions?

Are you starting with a dull razor? I find that if I USE A SHAPTON 4000 and 8000 first, the n finish with a coti it puts a buttery edge on it... Maybe yours is just a really high grit coti?

If you have slurry on it and do back and forth strokes or circles does the slurry get dark with metal pretty quick or at all ? If it is a very hard coti it might be a 'finisher' or it may just be a dud.

Originally Posted by mackie

I have a nice old coticule stone that is about 1 1/2 X 8. I lapped it and aside from some hairline cracks from age it is a nice stone. However, no matter what I try I can't get it to put an edge on my razors. I have owned and sharpened about 50 razors over the last 30 years or so, using various stones and means. Using the coticule though, no matter what I try, and I have tried the unicot and dulucot methods, and just water and end up with a razor that is not sharp. Every time I try I end up finishing it on a different hone. It just don't work for me. I hate to do it but I think I am going to use oil on it and try that. I don't know what else to do. Any suggestions?

Inquiring minds want to know. Why out of the blue would oil be a choice? After 50 razors doing what on what stones?? Why not just try 3 strokes more on the Coti, 5 strokes, 7 strokes, 10 strokes and see what happens? What happens with 3 strokes on .5 something after what you have done so far?? Have you tried using a light slurry to water??

How about some pics? Hairline cracks? Does your fingernail catch when you run it over them? Personally, I don't like the Coticules with all the cracks, and inclusions all over them.
I've seen some for sale for razors that shouldn't be. That's just my personal opinion. I like them nice and clean and smooth looking. When it comes to razors,the smoother the stone, the better.

I've seen some on the web I wouldn't use for sharpening tools, let alone razors. Razors have such a fine edge, not every Coticule is good for them, even though you'll be told they are. Some people just want to make a buck and that's unfortunate. Also, forget about the Dilucot and Unicot Coti methods. It's not working for you, is it...Don't pigeon hole your self into some specific or dogmatic way of sharpening when it comes to Coticules. Learn your stone. Build a slurry, get an old razor and do some back strokes. See how long it takes for the slurry to darken. That's a good indicator of how fast the stone is.

The Coti's that are greenish, are normally slow, and don't cut very fast. They're usually better finishers. The pinker, yellower one are normally faster.....But these are naturals, and there are variations and exceptions to the rule. I know people who have bought 7 or 8 Coticules until they found one they like, me included...I have quite a few....
Let's see some pics, and maybe we can give you some advice. Don't use oil. This is my personal opinion.

BTW, Where are you in Florida...?

A few ways to use a Coticule... Distiled from everyone's posts above

1. Dulicot and Unicot
2. After the bevel is well and truly set using the "one stone hone method"
3. After the razor is shave ready at about the 8k level as a finisher with a light slurry then clear water
4. As a true finisher with only clear water

If not any of these methods work especially #3 and #4 then it is time to maybe hook up in person with one of the guys that knows Coticules really well and can test your stone..


After having several discussions with the "Try oil on a Coti" guys and asking some fairly simple questions about how they tested their Coticules for oil absorbtion and getting no answers, not even for the simplist of tests I concluded that I ain't putting oil on my prized Coticule.. The Smith's solution is safer, and gives good results on real oil stones so you might try it instead, myself I have plenty of stones that I could use if I want sharper... The object of my use of a Coticule is a nice soft edge on Sheffield steel so sharper is not needed...

A good hone will perform well irrespective of the lubricant you use. Are you sure this is a coticule suitable for polishing straights?

I'd suggest you start with a blank slate and re-read the unicot and dilucot papers on coticule.be (the other stuff on there is also very interesting, by the way) and start with doing only unicots. It is a much more straight-forward method and you'll result with an edge identical to a dilucot edge and if it is impossible for you to get a good shaving edge doing unicot than it will definately be impossible to get a good shaving edge doing dilucot on the smae stone with the same razor.

unicot
dilucot

Strange to hear that unicot doesn't work, because I've done that quite a bit and have not got one unsatisfactory result.

Please note that for a coticule to work (and logically I assume for all other types of hones) the bevel must be set properly (I use the thumb pad test, looking for an edge that really sticks to my wet thumb).

Also note that coticules on water alone do not add sharpness, they only polish the edge, adding smoothness. All the sharpening of the edge has to be done before using water only.

I am inclined to believe (along with a fair number of very experienced coticule users) that there is no such thing as 'bad coticules', only 'different coticules' that can demand quite a wide variety of approaches (mainly in doing dilucot, though). That is, unless we're talking about a coticule with minor inclusions that come loose while honing; they will just damage your edge. I have five coticules, all different strata and only one that is unusable as it has such inclusions. You can see these inclusions with the naked eye even in a slurry, in mine they look like grains of sand.

Some coticules are less suited for establishing a bevel than others, but if the bevel is set on another stone there should be no problem.

To answer your questions, First off I am using a razor that was shave ready and slightly dulled on a glass. 2. When I start with a slurry it gets dark within about 8 or10 passes, 3.Some on here have said they got good results with oil when they didn't with water, that is why I said I might try oil. 4.I have tried heavy to light slurry to water as I said, Unicot dilucot,, Hundreds of passes, and again on a previously sharp razor,5.The cracks in the stone are so minute, they can,t be felt with a fingernail,and it is a yellow stone, 6.As for the hardness of the stone it is soft and gives the feeling of honing on chalk when using it. 7. I have tried both methods three times each without getting a shavable edge, however I will not put tape on my razors for any reason. I have established a nice bevel on them they way they should be..

Originally Posted by mackie

I have tried both methods three times each without getting a shavable edge, however I will not put tape on my razors for any reason. I have established a nice bevel on them they way they should be..

My suggestion is watch Lynn's video on "One stone Honing" he also does NOT use tape, and is starting the razors off a bevel set just like you, the Killing of the Edge on the glass is probably not needed, but it won't hurt if you do it right...


Quick test, subsitute in a Norton 8k for the Coticule and do everything the same if you have one, or someting in that range, Thuringen, Chinese, and see what the outcome is...
That will test your system, if the Norton works then the system is sound and you have to tweak for the Coticule...