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. :gl:

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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?

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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.

Attachment 100364To 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..

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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..

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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...

I cant better the advice given already, I'm only chiming in because your coticule looks nearly identical to mine which seems to have the same bother of being able to shave very well but, not giving smoothness as much.
the only difference being mines seems very hard - not soft like yours - but strangely chalky to hone on like your coticule.

The only thing I can advise is slightly slow down your strokes and lighten them up a bit, my theory is the chalkyness indicates alot more particles hitting the edge than a smoother silky slurry, IMO creating a rougher edge. also does your coticule seem to slow down and hold back the speed of your strokes? sort of clinging onto the razor?
I can set bevels with little pressure after dulling on glass with the coticule I have. It seems the slurry cuts quick.
I would advise when finishing to try finishing on one half of the stone and then the other half to see if there is a discernible difference in edge.
I have found a marked improvement finishing on one half as opposed to the other.

I have an extremely hard la verte and bbw, both have very little inclusions and I have no problems getting keen smooth edges from either, but this coticule still gives me trouble sometimes, even after 2 years, I'm experimenting with it to the extremes now; very minute details like speed of stroke and subtle pressure differences and where on the coticule to hone... yes coticule honing has driven me nuts ;)

I wish you luck with your coticule and I will keep on at mine and hopefully find a technique to work with these sometimes stubborn rocks...


regards Alex

All I can offer is one experience. It was an expensive coti that I couldn't get to "hit" no matter what ..... until I took a shave ready razor to it and after shaving with it once ... next day did water only finishing strokes on that problem child coti. The edge was definitely improved. So I don't know if that is any help. I did have a member send a coticule to me a couple of years ago for testing.

He had already sent it to someone else and they said they couldn't do anything with it. I tried and tried, one method after another, and had to give up in defeat and sent it back with condolences. So like I said before .... best of luck with it, hope you can figure it out.

Opinion follows:
For a finisher once it is flat enough never lap it again.
Use the rubbing stone to help keep it flat enough..

If the shave is not smooth enough hone with lather and rinse well when done.

Use as light a touch as you can. Slow and deliberate.

Five/six stroke pairs only,,,, strop at least twice and if it still feels dull
give it five more strokes on the hone.

Pull strokes work...I have been astounded with the edge from
only a small coti slurry stone.

Coti slurry on canvas is often a good thing in moderation.
(a bit of slurry from any finisher on canvas can be good.)

Once a razor is shave ready sharp stick to the finisher hones
8K and finer or your natural finisher. Almost no shave related
dullness justifies more grinding....

Are you evaluating the edge during the process? If you can get it to easily pop arm hair, try up to 30 laps at almost zero pressure, mine will tree top arm hair at this point and be shave ready.

Quote:

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Originally Posted by mackie

First off I am using a razor that was shave ready and slightly dulled on a glass

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..

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I get the 'no tape' philosophy, but if you've put the edge to glass, you're essentially resetting your bevel anyway, so...

A simple, guaranteed way to check what kind of edge your stone can produce is to first get the razor smoothly shaving arm hair, then add a layer of tape and switch to the test stone to set a secondary/micro bevel. The reasoning is a) it's MUCH faster, even with a slow stone, and b) you can be sure the resulting edge is 100% due to your test stone. I'd do 10 light strokes, check the edge, and repeat.

If you don't go overboard with it, reestablishing a primary bevel afterwards won't be significantly different than doing so after dulling the edge on glass, imho.

Dulling a razor on glass is a bad idea on a razor that shaved well or
almost well yesterday. It is OK in a honing contest but it is
not a good idea if you want to shave.

What it takes to refresh an edge is way less than what it takes
to recover from dulled on a tumbler.

Bad idea... Dulling a razor on glass.... it is.

+1 on the above

The only time I'll intentionally dull a razor is if I detect a crumbly/chippy edge during bevel set, then I use the corner of my 1k and run a few passes, then start over on the 1k

On the dulling on glass: It is not bad if you know why you are doing it. It is only applied when an edge has gone beyond needing a touch-up and is in need of some more serious attention on the bevel-level. It has nothing to do with a honing contest and is merely a tool, not a means to prove anything. It is not a requirement of any kind, just something some people use as an extra check point, to make sure they start off on a clean, even bevel, that's all.

It is done because (a) as rodb mentioned, if the edge has minor defects that will effect the ability to take an even bevel (or to even out some of the toothmarks left from establishing a bevel on a coarser hone) and (b) to be sure that the bevel is re-established completely and evenly (i.e. that the two plains meet evenly across the entire edge). When going from a coarser hone to a coticule, a glass-dulled bevel will not take much more than two or three sets of half-strokes (or back-and-forth strokes) to be re-established. When done right, this shouldn't take more than a few minutes.

And mackie, you say that you have tried both dilucot and unicot multiple times without succes, but refuse to use tape. That is of course your good right, but adding tape before the refining stage is crucial to the success of honing using the unicot method. The idea is to establish a good, clean bevel on slurry, refining that bevel slightly and then adding a layer of tape as to increase the honing angle to establish a secondary bevel, with diluting the slurry with a few drops of water. Or to quote the article on coticule.be:

"If the Coticule, used with water, is allowed to work on a narrow strip near near the apex of the blade, it will remove enough steel to refine the edge, gradually slowing down as a new flat region grows. One layer of tape added to the spine is sufficient to divert all refining action to the tip to the bevel. Because the new, secondary bevel is only altered by the smallest possible degree, it must be allowed enough width, in order to add the desired keennes to the initial bevel. The seconday bevel is cut with a very light slury before maximizing sharpness on the Coticule with clean water."

http://coticule.be/unicot.html

So basically you didn't do the unicot, you did an abridged dilucot. And those sadly do not result in any decent sort of shaving edge. I know, I have done this before myself. For unicot, adding a layer of tape is crucial to be able to quick-hone the very tip of the edge with light slurry and after that, polish it on water (basically what northpaw said).

A coticule with water only polishes, so if you go from a medium slurry to water you will see no improvement in sharpness (or keenness) because what slurry does is sharpen an edge (i.e. grinding away metal at the very edge) but also ever so slightly rounding it. When diluting this dulling effect is reduced with every dilution (evening out the tip of the edge), until you end up with as sharp an edge as possible on that coticule, after which you polish the edge, adding smoothness. That's why when honing with a coticule you have to end up with a slurry that hardly contains any particles before going to plain water.

A dilucot (thinning down the slurry gradually) is one-stone-honing on a coticule, and tape is not a requirement. Whether you do it without tape, with one layer, two layers or with (hyperbolically) seven layers, that number of layers must be consistent throughout the diluting process, otherwise you will end up with greatly varying and greatly unpredictable results due to a varying honing angle (or you end up doing a very elaborate unicot).

I have a La Veinnette natural combo on which it took me at least ten (but probably closer to fifteen) tries to get a good edge doing dilucot. I almost thought the problem was with the hone.

Oh, and those lines on your hone ar not cracks. If you can't feel them, they are probably manganese inclusions that do not impede negatively in any way on the hone's performance.

Many thanks to everyone who contributed to this thread. A lot of info here. I will keep trying.