Thread: Help with choosing a finishing stone

Originally Posted by Chimensch

OK, here comes the "troublemaker" ... a lot of these hone discussions remind me of audiophiles arguing about equipment that reproduces frequency ranges that the human ear (or at least mine) is not capable of hearing. For many years I went from a Swaty to the strop and the results were fine. Now, that I've been educated by SRP, I go from a coticule to a four-sided paddle strop with Dovo Red, Dovo Black, chromium oxide and 0.25 micron diamond paste. I am delighted with the results. I recently bought a Chinese 12K out of curiousity but it didn't improve anything so I don't use it anymore. I'm not criticizing those who have made hones into a hobby. All I wanted to do was to find a system that gave me BBS with no irritation. Having found that, I'm moving on and won't be experimenting with any more hones.

I do wonder about how much people argue the benefits of their many hones and razors needing different hones as a method of justifying all the hones that they own.

Like you my goal is a smooth confortable shave. So I have no desire to buy many many hones, which is part of why I think I want to lean toward synthetic hones instead of natural as it seems that people who have say numbers of coticule's note that one of them is so coarse it is like an entirely different stone.

Originally Posted by PonderingTurtle

Like you my goal is a smooth confortable shave. So I have no desire to buy many many hones...

But I just read him say that his results before were fine, yet he bought more honing equipment and began experiencing better shaves
You'll never know what lies beyond unless you venture out

Well, with that title, I'm sure that my crucifixion is immanent! When it comes to natural stones, the only sensible approach is to deal with a reputable, knowledgeable dealer. Our own Howard of The Perfect Edge has decades of experience with Belgian stones and has seen thousands. If you explain what you are trying to achieve, he can suggest a stone for you . The highest grade of Coticules with any size to them is Kosher Grade. There is a higher grade but it comes in small pieces only usable to hone small chisels like Japanese cabinet makers like to work with. Two other authorities are Gerhard (Gary) Richter of Timbertools in Canada and Rob Celis who owns the Coticule mine in the Ardennes. When it comes to German Natural Water Hones there are a number of knowledgable people here at the SRP. The newer stones are being actively sold by Timbertools and The Perfect Edge. Vintage German Water Hones are another story. I have owned, sold and traded many of these stones and can tell you that they are superb finishing stones. I am witholding myself from saying that they are the best because I am waiting for our own O_S to find me a Japanese Natural Nakayama Karasu Water Hone which he promises me will rock my world! And that brings me to the next subject. If European Natural Water Hones are a complicated, dark labarynth Japanese Natural Hones are impossible to understand without being guided by a Master Japanese Honemeister. Our own revered O_S is the person that I believe has the trust of the SRP brotherhood although perhaps other members can lenghten the list. Finally, the subject of synthetic stones come up. The Norton 4K/8K is the stone that most members start with. If properly used, an edge can be obtained off the 8K side that will yield a respectable shave after stropping. Our founder Lynn Abrams who has honed more razors than anyone that I know uses this stone as his starting point. Most of us know of his famous Pyramid honing scheme. The Shapton stones are another question. They cut faster than any natural stone. The reason why this is so is that the cutting element in the Coticules is very fine Garnet at about 15 to 35%, in a clay/volcanic ash matrix, in the Eschers the cutting element is Silica, SiO2, at about 15 to 35% in a chalk matrix but in the Shaptons the cutting element is a ceramic, the next hardest substance next to diamonds known to man. And the % of cutting element is about 80% or more in a polymeric matrix! This is typical for composites, the less organic binder the better the performance. Lastly, lapping stones. I've used the DMT 325 grit lapping plate for years. It works well but has two disadvantages 1) it is slow for a lapping stone requiring many hundreds of strokes to properly lap a hone and 2) stones have a tendency to "stick" to the DMT due to the surface free energy inherent to the swarf. I recently acquired a Shapton DGLP and WOW, what a phenominal leap forward this lapping stone provides. Not only is the flattest thing imaginable but it cuts super fast compared to the DMT and there is NO, I repeat NO tendency of the stone that you are lapping to "stick" to it, what a relief! Now I readily admit that my favorite thing to do in this wonderful hobby is lapping stones, go figure, but I love it. Now with my Shapton DGLP it has become, well, I can't really say it on a public forum, so let's stick with Dreamy. There is my 3 cents worth!

Originally Posted by PonderingTurtle

I do wonder about how much people argue the benefits of their many hones and razors needing different hones as a method of justifying all the hones that they own.

Like you my goal is a smooth confortable shave. So I have no desire to buy many many hones, which is part of why I think I want to lean toward synthetic hones instead of natural as it seems that people who have say numbers of coticule's note that one of them is so coarse it is like an entirely different stone.

A certain type of steel does behave differently depending on the stone that sharpened it. The rate that a stone abrades steel is a major contributor to the kind of edge that is left; A steel with lots of abrasion resisting alloying elements requires an aggressive stone to achieve a nice edge, but that same stone will leave a ragged edge on a softer blade made of simple steel. The difference isn't night and day, but it's there. The hardness/softness of a stone also affects the edge depending on the type and hardness of the steel, and in many cases brittle steel requires a stone that's gentle so as to avoid microchipping.

About the coticule, the ones that are said to be really coarse (at least in my case) are ones that I've picked up on ebay. If you were to go through a reputable vendor (like Howard), they would be able to tell you for sure that a certain stone is worth using as a finishing hone on razors. No guess-work what-so-ever.

But as far as the original thread is concerned, pastes generally cover up whatever hone was used prior to the paste and render most edges about as good as can be, so there is very little to gain by going from a coticule to a slightly finer finishing stone and then finishing off with the paste, the difference probably won't be noticeable.

Russell, Tim Zowada reports that going from the Coticule to the Escher to the pastes does produce a positive, noticeable difference. I have to say that this is my experience as well. Actually, I use the Belgian Blue Stone with a slurry instead of a Norton 4K, a Coticule with only water instead of a Norton 8K and then finish on an Escher B/G followed by an Eacher Y/G followed by a 0.5 micron Cr2O3 3M Mylar film followed by a horse shell leather strop. A lot of work but it pays off.

It just depends on how many laps you do on the CrO paste, throwing in a finer stone just decreases the number of passes you have to do on the paste to get to the same result.

It's like saying that jumping from the Belgian Blue to a Y/G Escher is nice but throwing a coticule in the middle makes things much better, you just haven't abraded as much material off with the first method.

The edge doesn't care how it gets down to that ~.4 micron width, right.

Does the path one takes matter or is it immaterial. Boy, that's one that everyone in the material science of metals grapples with. I haven't spent much time studying metals but I have studied polymers a good bit and I can tell you that the path that one takes to get from state A to state B seems to be the determining factor in the development of the final properties. From what I've read about metals, the situation is similar. About the only things that I know about that are path independent are Thermodynamic State Functions, in fact, path independence is a requirement for a function to be a TSF. In short, I wouldn't bet the farm that it doesn't matter how one gets from one point to another, in fact the great variability in the results obtained by one honer versus another is probably caused by this path dependence of getting from A to B. It is also probably at the root as why one technique and one set of stones works great with one razor and not with another

But we're talking about abrading steel off of a blade, not about playing with it's thermodynamic properties. The properties aren't changing, just how much metal that is at the edge of the bevel.

You can remove the same amount of material with a chinese 12k as you can with a DMT D8C, it'll just take you a few years and the properties of the steel will be no different.

If there is a difference, what would it be?

Either the hardness, grain, or composition of the steel would have to change to alter the blade's edge properties, which doesn't occur unless there are harsh chemicals involved or extreme heat.

Originally Posted by blaireau

It is also probably at the root as why one technique and one set of stones works great with one razor and not with another

I went into this a little bit above and there is some truth to it. It boils down to what gets the maximum potential out of the steel in question, but as long as the edge is the same final width (the upper bound that the steel matrix will sustain), the lower grit stones don't make a bit of difference.

When you are dealing with energy you are dealing with different forms of it. These forms can be transformed into each other but they are fundamentally different. We are applying mechanical energy into the metal. This can have a similar effect as if we were applying thermal energy. In fact, some chemists are investigating how to drive chemical reactions mechanically instead of the old standby of thermal energy. I recently was awarded a provisional patent using mechanical energy to create Perovskite ceramics for High Temperature Superconductors by using a relatively new chemical process called reactive milling. If you're interested in this, Google Professor Serge Kaliaguine of Laval University in Quebec, Canada or Professor Jeffrey Moore of the University of Illinois, you may find it interesting.