ShavingUniverse.com

Register a free account now!

If you are registered, you get access to the members only section, can participate in the buy & sell second hand forum and last but not least you can reserve your preferred username before someone else takes it.

Pictures of bevels and edges thread at Shave Ready

Thank you Bart and Ralfy for the warm welcome.

I don't mind honest criticism at all. Heated debates are even more welcome :)

To jump in, a couple of members on another forum - not razors - saw the pictures and responded that the edge only as good as it's bevel, and that a 30K edge/scratch pattern should look different. So I tried making the bevel really smooth, but the resulting shave was very sharp.

My theory is that as the bevel gets smoother, it get weaker since it lacks the corrugated-like structure, causing it to flex or bend more readily. This is good, but too much makes the edge like foil. Contributing to this is the fact that the edge is the razor is so thin anyway, I can't help but wonder if the grit of a stone is actually capable of abrading or piercing through one side of the edge as it gets so thin.

Any thoughts?
 

Paul

Well-Known Member
Tom,

As the guy who sold me the Shaptons that sit idly by on my shelf :lol: , let me also extend my welcome :thumbup:

jendeindustries said:
Please, Log in or Register to view quote content!

My experience is similar

jendeindustries said:
Please, Log in or Register to view quote content!

You could be on to something here, Tom. If I spend too much time on the 30K, the edge seems to become "sharper" instead of smoother (no, we don't need to get into that discussion again). After 5 to 10 strokes on the 30K, it always felt like the edge was less suitable for shaving. It may well be that it was being overhoned as Lynn suggested to me one day. I'm reluctant to say anything definitive because I don't really care for the synthetic stones and have stopped experimenting with them for the most part.

Welcome again :)
 

tat2Ralfy

Well-Known Member
My take on it is that maybe just maybe the 30k edge is too sharp, too fine and the steel at the very edge is too thin to stand up to a shave.

But heck what do I know?

Warmest Regards
Ralfson (Dr)
 
Thanks, Paul.

The Shapton 30K Edges, to me, are right in the middle of sharp and smooth. It's yet another unique option in finishers, and one which I have become quite accustomed to as my edges have improved. To each his own, and it's all good with me - just for the record.

I think there is the capacity to easily over hone on the glass stones - they are quite sensitive. That's one of the reasons I have gone back to the pros. They seem to abrade more evenly, too. Under the scope, they leave similar scratch patterns on the bevel, but they work differently. I don't have the words to describe the difference, other than "clean" pro scratches vs. "shiny" glass scratches. FWIW, I think I have gained good control over both the glass and pros.

Ralfy, you are on to what I've often wondered. I've been in conflict about how to approach it...

The first is that the lower grits leave the "bottom" of the scratches that you eventually try to get down to. In this light, the steel is as thin as the scratches are deep. The other approach is that with the erasure of each grit's scratches, the steel gets thinner and thinner. Perhaps doing too good a job makes the steel at the edge loose its structure, much like the corrugated-like structure.

Looking at these ideas, they seem to mirror the pyramid and progressive methods, respectively.
 

RicTic

Well-Known Member
jendeindustries said:
Please, Log in or Register to view quote content!
This is open to anyone. Is it at all possible for the same foil like edge to appear after a session on a coticule?
I ask because I own a ERN razor which I've had great success off a unicot, but everytime I attempt a dilucot, I end up with the same result. An edge that seems too thin! I can even feel it on the strop.
The steel on this particular ERN feels different from my other razors...not as malleable (for want of a better word?)
 

Bart

Well-Known Member
I'm afraid the corrugations theory is based on assumptions that have been invalidated by scientific research. High resolutions SEM images of razor edges do not show any substantial presence of corrugations at the bevel that could be expected to influence the structural strength of the edge.
Here's a SEM picture from Prof. John D. Verhoeven's excellent study "Experiments on Knife Sharpening". It shows the edge of a straight razor. Left image is the tip of the bevel at 3000X. Middle and right image shows the bevel sides at respectively 800X and 750X. Unlike optical magnification, Scanning Electron Microscopy offers excellent depth of view. I don't see anything that could possible "reinforce" the bevel.
[img=600]http://www.coticule.be/tl_files/barts_pics/Prof-Verhoeven%2CSEM.jpg[/img]

It is clear that the abrassion during the final honing stage lacks the penetration for single abrasive particles to create the structures that you guys are speculating about, and/or the plastic shaping that takes place overrules the formations of grooves.

But even if they had been present, the assumed corrugations would not cause extra sturdiness, because they would not be added to the bevel but rather substracted from it. Allow me to elaborate on that. Since the choice of hones does not alter the bevel angle, it is clear that on the same razor, the resulting bevel will have the same base width regardless of the hones used. It can be measured as the thickness of the blade where the bevel starts. Let's imagine we would take some kind of laser cutter and separate the bevel from the blade. We could put it on the table on its base. So we now have a triagular shape in front of us. The height of the triangle is also a near-constant. I'm using the term "near-constant", because a keener triangle will be slightly longer, but that has no relevance for the (invalid) corrugations theory.
Here's a quick drawing:
bevel-shape1.jpg

In this situation, the non-corrugated bevel always contains more steel than the corrugated one, because you can only cause the corrugations by making grooves. (as revealed above: we have no practical means for that, but let's say we had a hone that could do it) If you later on remove these grooves by polishing them out, you'll end up with exactly the same bevel as you started with. It would only start a bit closer to the spine of the razor and end the same distance less (your blade is wearing smaller). Anyway, the same triagular shape with grooves would be slightly weeker than the idential shape witout grooves. The difference won't be big, but it would in no case be stronger.
bevel-shape2.jpg

But as said, this is all irrelevant, because such corrugations do not exist at the bevels of razors that were honed to any kind of shaving state.

What I believe is going on when the edge of a high grit synthetic hone prematurely fails is far less esoteric. It seems logical to me that a hone with the extremely fine particle size of the Shapton 30K has the capacity of defining a bevel at its keenest possible shape. The very tip of such a bevel is both extremely thin and extremely delicate. That delicacy has a negative impact on edge retention. It's a simple truth. There are a few interesting solutions for that problem:

1. finding steel that provides maximum sturdiness to withstand the stresses caused by shaving with such ultra-keen edges. There sure is difference between razors in that field.

2. settling for a slightly less keen, but also more durable edge. I believe it will also be a more comfortable edge, but that's an entirely different discussion.

You may wonder if a slightly deteriorated ultra-keen edge doesn't meet those terms. But that forgoes the nature of edge deterioration that invariably gives better performance with edges that were sharpened to a level that could both support the steel and the cutting task at hand than with edges that were teared apart upon impact with forces they could not withstand.

3. using the increased strenght of a seconday bevel, created at obtuser angle. With these kind of ultra-keen edges, angles above 20 degrees may very well be the best option. (requires 3 or more layers of tape). The bevel angles found on ultra-keen commercial razor blades produced by the brand Feather, seem to agree with me on that.


Kind regards,
Bart.
 
Bart, the Verhoeven report is great. I haven't read the whole thing, but just out of curiosity, did he ever shave with the razor?

Anyway, I see what you mean by that 3000x pic. There are minute high and lows points, but they seem to not have any influence at the very edge, overall.

Your last picture of the corrugated edge is exactly what happens if you "go to far", or over hone with the Shaptons and Choseras in particular. There is a fine line between getting the edge down to that very tip, and then going past it. Little teeth (very little) appear at 100x. In the spirit of #2 above, I think "cleaning" a bevel at 5K pro/Chosera or 6K glass is essential. The edge at that stage stays pretty well intact, and after the 8K pro/glass or 10K glass/Chosera the metal begins to get very thin if you try for perfection at the 15K, 16K and 30K levels.
 

Bart

Well-Known Member
jendeindustries said:
Please, Log in or Register to view quote content!
The Verhoeven Study should be mandatory reading for every one who wants to explore the bare physics of sharpening. Here's a link to the
Please, Log in or Register to view URLs content!
.
The razor's edge from the picture was honed by one Mr. William Dauksch who "has used a straight razor
for several decades". I don't think Verhoeven himself shaves with straight razors.
jendeindustries said:
Please, Log in or Register to view quote content!
My point exactly.
jendeindustries said:
Please, Log in or Register to view quote content!
I can't speak for the Shaptons, but I own a Naniwa Chosera 5K and a 10K. I can't say I ever experienced what you described. I have experienced cases of microscopic chipping of the very edge, on Coticules and other hones, but it seems completely razor related. The problem starts with a few microscopic chips missing at the very edge, immediately after honing. There occurrence builds up during the subsequent shaves, and I've always attributed the problem to brittleness of the steel. In the vast majority of cases, I have been able to completely solve the problem by augmenting the bevel angle with adding 2 layers of tape to the spine. It's been a while since the Chosera saw any use, but I should be able to recreate the results of your teeth theory with my Chosera, if you provide a procedure for that.

Kind regards,
Bart.
 
Top