Thread: Hones and Edges Under the Microscope

Tim,
Thank you so much for going to all the work involved in getting the razors ready, the stones ready, and the photos taken. The pix are truly informative. I'm sure this study will ignite weeks of discussions.

Can you put up photos of the arkansas @ 200 to compare?
Close ups of the hones really gives a clue to their potential finish don't you think?

Great work!!!!

PuFF

Thank you very much for taking the time to conduct this study and share your results. When you say "without a slurry" does that mean that you used the stones dry, or did you use the stone wet without rubbing it first and assume that a slurry did not have a chance to form in only 10 strokes? I am assuming that you used the stones wet but I am just making sure. Also it might be benificial to test out bench hones or stropes pasted with chromium oxide and diamond pastes if time permits. It seems like many people believe that diamond paste can produce a slightly sharper edge while chromium oxide can produce a more "comfortable" edge to shave with; however, it would be very nice to see pictures to really see the difference. I really love empirical evidence to back up statements!

Originally Posted by heavydutysg135

It seems like many people believe that diamond paste can produce a slightly sharper edge while chromium oxide can produce a more "comfortable" edge to shave with; however, it would be very nice to see pictures to really see the difference. I really love empirical evidence to back up statements!

I believe you are mistaken or at least confused on this point. For a given grit, chrome oxide and diamond produce similarly sharp edges, but the chrome oxide will be more comfortable to shave with. However, diamond is available in much finer grits that will get you to a sharper edge.

Regarding empirical evidence: If a member notices that chrome oxide shaves smoother and more comfortably than equivalent grit diamond, that *is* empirical evidence that chrome oxide edges shave smoother than equivalent diamond edges. These photos, while interesting, are *not* empirical evidence of any statement about shaving quality; they are empirical evidence of bevel smoothness, scratch density, etc. It may not be obvious to the newer guys, but these pictures don't actually tell you much about how sharp the edges actually are or how well they shave, they just tell you how smooth the bevel is, and something about how smooth the fin is. But they don't actually tell you how thick the cutting edge really is, or how it feels on your face. So it's easy to invest more meaning into these photos than is actually there. There is a common mistake among newbies, we get a lot of posts along the lines of "what does a sharp edge look like under a microscope" and there's no answer for this, because while sharp edges tend to look a certain way, dull edges can also look that way.

I'm with mparker most of the way here. These photos give us some really good clues as to why we are experiencing the different effects and sensations from different hones, but they don't prove objectively which edge is most effective.

I will say that a .5 micron diamond edge seems sharper to me than a .5 chromium oxide edge. This is based solely on shaving my rather weird beard and doing the hanging hair test on my hair. It could be that the diamond edge is more akin to the slurry results in the photos above, and that the toothier edge just works better for me. Or it could be my technique on the strop.

That's why I'm particularly interested in comparative shots of diamond edges vs. chromium edges.

As Forestry Prof likes to say, this is all just another data point.

Josh

It turns out that Tony Miller and I were talking about doing a photomicrographic study of different hones just a few weeks ago. I even contacted a professor at a local university about having him make a microscope available to us for this work. I really like the way you correlated stone texture, edge texture and especially the edge texture of different stones with and without a slurry. Tim, this is truly ground breaking work, and your methodology is very scientific. Do you have a technical backround? Getting back to the results, I would like to try to summarize them in a systematical way:

1) The presence of a slurry has the most dramatic effect on the edge of a blade when it is honed with a Belgian stone. The second greatest effect of the presence of a slurry is seen with the Chineese stone. In both cases the effect translates to sharpening, i.e., the removal of metal to yield a sharp edge.

2) The presence of a slurry yields the smoothest edge with an Escher stone. These prized German stones have a great reputation for being the best at polishing the edge of a razor and here is the photographic evidence.

But Tim goes beyond merely confirming photographically what we all kind of knew, his work suggests how to hone to best effect. Once a bevel is established with a Norton stone or equivalent, should we not sharpen it using a Belgian stone with a slurry and put the final polish on it with an Escher stone with a slurry? That's what the pictures indicate to me, what do all of you think? Also, a legendary type of hone is missing from all this, Japanese hones. Tim, would you dare to delve into that world? Thanks for your beautiful work and your "a picture is worth a thousand words" approach. I am learning a lot from looking at and thinking about your pictures.

Originally Posted by rgdominguez

Once a bevel is established with a Norton stone or equivalent, should we not sharpen it using a Belgian stone with a slurry and put the final polish on it with an Escher stone with a slurry? That's what the pictures indicate to me, what do all of you think?

I think you are overanalysing this While these photos tell us a lot, they don't invalidate all the things we already know. Things like "chrome oxide is both extremely inexpensive and extremely effective for the final polishing step". Eschers are awfully expensive, which means they've got a huge bar to leap to become the preferred finishing stone, especially after you've sprung for the nearly as expensive coticule.

I don't recall saying a word about invalidating anything. The photos do increase our knowledge and illuminate the way to improving our process hopefully making us better honers. As to the pastes, they were not studied by Tim yet and so the jury is still out on what they make an edge look like. An analysis of results may be called overanalysis by some but it is merely trying to distill something from a systematic though incomplete study. Mparker, I appears to me that you think that everything is already known about honing, a very dangerous attitude that doesn't allow for further revelation. At the turn of the twentieth century the physicists of the world thought that they had it all down pat and then Einstein came along and shattered their smugness and improved our understanding of time and its relationship to measurement. The human brain is a gift from God intended to elucidate the workings of the world. It does not respond well to being cast into concrete!

I think you are making assumptions about what I think that are unjustified, incorrect, and frankly quite insulting. I am skeptical that these photos show the things you think they show, because I have seen these things in my own microscope and they did not then show what you think they show now. Scratches on the bevel are all fine and good, but the bevel is not the edge and it is important to keep this in mind. Tim has performed a fine service posting these photos, but he is not the first person to have gazed upon these sights. Perhaps you are new enough at this whole thing that you did not realize this, if so you can certainly be forgiven your youthful exuberance.

I will say again: These photos tell us that certain hones, used certain ways, produce certain textures on the bevel. By themselves they tell us squat about how these edges shave. That we know from experience standing over the sink. Going from photos to making deductions about the proper way to hone is extremely premature and completely unjustified based on the photographic evidence alone. "That's what the pictures indicate to me, what do all of you think?" I believe you said. I criticized this attitude because I believe it to disparage the accumulated experience actually shaving with these edges; experience that although indirect is much more relevant than these photos. We already know how the edges produced by the hones feel, we already know how sharp they can get our razors; the photos do not change this. As for pastes "They were not studied by Tim yet and so the jury is still out" is a very mistaken attitude that implies we know very little about the pastes, and this is simply wrong. We know how the various pasted edges shave already; photos do not change this, and no photo can change how they shaved yesterday or how they will shave tomorrow; all the photos can do is explain the experimental evidence about them that we have already accumulated. Perhaps they can suggest avenues to explore, but that's a far cry from stating that the photos show we should use hone X one way and hone Y another way. But we cannot throw out what we know about the various pastes and hones just because of some photos that show us only the bevel and not the edge.

Now if somebody gets some scanning electron microscope shots of the edge and gets them mapped into an accurate 3d representation, then we can maybe start making some hard deductions about honing techniques and tools. But these aint they.

Originally Posted by rgdominguez

I don't recall saying a word about invalidating anything. The photos do increase our knowledge and illuminate the way to improving our process hopefully making us better honers. As to the pastes, they were not studied by Tim yet and so the jury is still out on what they make an edge look like. An analysis of results may be called overanalysis by some but it is merely trying to distill something from a systematic though incomplete study. Mparker, I appears to me that you think that everything is already known about honing, a very dangerous attitude that doesn't allow for further revelation. At the turn of the twentieth century the physicists of the world thought that they had it all down pat and then Einstein came along and shattered their smugness and improved our understanding of time and its relationship to measurement. The human brain is a gift from God intended to elucidate the workings of the world. It does not respond well to being cast into concrete!

Well, I think Niels Bohr, Max Planck et al can rest easy for the moment.

The problem with dipping into Japanese waterstones is the variety and their cryptic naming schemes. Unless we get someone who knows a heck of a lot about them to supply the stones (and what collector is going to give up any great stones for testing?) and advise on them we won't be able to draw any conclusions. At least with manmade stones and natural stones like coticules we can duplicate the results at home (approximately with the natural stones anyway).

I have noticed the texture of a coticule varies a little under moderate magnification depending on the colour; the green looking slightly more textured for me at least iirc.
I noticed there was no TOS either. I'll have to have another look at mine.