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Bevel Tip and Magnification

wdwrx

Well-Known Member
I'm not really sure if this is a question or how to phrase it properly if it is, but I've been looking under the 'scope a lot ever since i embarrassed myself sending a poorly honed razor to Denny and I'm wondering wether I've got general issues with chipping, or wether some "texture" along the very tip of the bevel is somewhat normal.

One thing I observe under the 'scope is something I can only describe as "a string of beads". It looks to be a faint reflection of light coming from the structure of the (aprox.) 0[sup]o[/sup] radius edge. It's present on every blade I look at, no matter who honed it, and varies in degree, sometimes with more occurring in small sections and less in others.

Also, at times there are some "flea-bites" that occur, where it appears that small sections of the very edge are missing. Some razors show this more than others. And, of course, used edges even more so.
I addition, it is common for me to observe a certain undulation of the bevel line. Nothing dramatic, nothing that looks like a mountain range, but more of a slight texture.

I've tried comparing what I see in my scope with various photomicrographs posted here and there on the web, but without knowing that the magnification is of equal degree, it's not of much use. I also don't give a lot of credence to the values of what some claim to get with their USB 'scope as, in my understanding, there are ways to arrive at the so-called magnification value other than multipying the objective element values. It's a marketing scheme IMHO, but TBH, i can't recall how it's arrived at.

The maximum I can magnify is 100x with a 10x ocular piece and a 10x objective piece, and it's at that level that I'm observing these flaws. Under 40x magnification, the edge appears perfect, and none of these features are detectable by TNT, TPT or RW's tissue test. Without fairly high magnification, I would be completely oblivious to their existence.

So, what can I do to further minimize these flaws? Is it a function of crap on the stone, pressure in the honing stroke or just something that happens? Also, is the "string of beads" (which I assume is reflected off the non 0[sup]o[/sup] edge of the bevel) a result of remaining slurry dulling? Is it even possible to eliminate that all together, or is it a function of the structure of the steel? (that .5 micron radius thing)
Or, am I just chasing ghosts?
 

TM280

Well-Known Member
Hi Chris,

I am assuming that you have looked over Tim Zowada's photos at SRP:
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and the accompanying photos of edges. The coticule bevels exhibit the slight unevenness you are talking about.

I see what you are describing fairly often (When I am paying attention...). Chips make me go back to the hone, but I don't really worry about the rest of it. I tend to look for uniformity of the scratch pattern. If it's shaving well then I guess that's the answer. But I look forward to hearing what others say.

regards,
Torolf
 

vgeorge

Well-Known Member
Chris,

A terrific, terrific question. I have been pondering this too, but since I am early in the game, I do not have an answer. I can 'understand' the usual best-test-is-the-shave-test-nothing-else-matters answer. That still leaves me scratching my head and not knowing what to adjust or change. :confused:

There is x% explained by a good bevel, and another ∆x% somewhat explained by polishing. Magnitude of x is still unclear to me, but know it is large. I know nothing about how to control (100 - (x + ∆x))!

Although my experience is not wide, I have had poorly finished razors, actually only one ;), by celebrated 'honemeisters' - and excellent couple of razors by people who were never known for skills in honing. Go figure. Looking forward to reading the discussion.

George
 

janivar123

Well-Known Member
I think you have too much magnification:p
and a loup of 10, 20 or 30x is probably easyer to use too

String of beads is probably just the reflection of the polishing marks

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Well if you hadnt known about the issue without magnification of that level...
Then i guess you dont notice when you shave and all is well
 

wdwrx

Well-Known Member
Thanks Torolf, I'd overlooked those. Some of the one's I've seen recently are Robert Williams' at 650x, which doesn't relate well to what I have. Some of the Veho brand USB photo are said to be 400x, but I'm skeptical of that, so I can't relate that at all without knowing if it's even on the same scale.

This is my dilema:
vgeorge said:
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I've tried all kids of attacks: lots of pressure, the least pressure, water finishes and oil finishes... DMT bevels and slurry bevels. But I haven't been paying enough attention to draw any conclusions, beyond vague hunches. And without a camera attachment, it's hard to carry the recollection over to the next honing session, if i even think to try.

Janivar, but that begs the question; do i notice? How do I know it couldn't be better?:D

I've take the liberty of re-posting Tim Zowada's photo's of his coti edge in hopes of better explaining what I see:
Tim_Zowada_-_Razor_Bevels_-_CoticuleWSSm.jpg
Tim_Zowada_-_Razor_Bevels_-_CoticuleNSSm.jpg
these are at 30x, and I can relate some of what I see by mentally extrapolating up about 3x. As near as i can tell, I see something that falls in between the two types of edges he's shown. His water finished edge closely resembles mine in the uniformity at approximate magnifications (30x vs. 40x). When I increase my magnification from 40x to 100x, my water polished edge then looks more like his slurry finished edge as he shows it at 30x. But in my 'scope, there is a bright, broken line of reflected light from the tip. I can eliminate that by changing the angle of the light. Any missing sections of the bevel wouldn't be large enough to call a chip (...well except one tiny one on my giant wedge, but I've chosen to just ignore that one:| )

But, don't get me wrong, I don't really look on this a "problem", as mentioned: if it shaves.... but more of a learning exercise. Just a path I'm exploring; I'm never standing still!B)
 

rayman

Well-Known Member
Chris,
It is not uncommon for someone relatively new to honing to experience what you are asking about. The fact is, and you will learn this sooner or later, your issue is not in the finishing of the edge but rather in the finishing of the bevel. The correct development of the bevel has two parts - the first is the bevel you see and the second is the sharpness of the edge you create.

You can create a bevel with a corresponding edge that is just sharp enough to make you think that you can move on. If you do, you will have the exact issues you are talking about and begin looking in the wrong place for the solution. So here is the answer to your question.

Build your foundation to perfection and the rest is easy. In other words, don't stop honing the bevel until you are able to easily cut arm hair at its base along all parts of the blade. When you can do that, you are ready to start to think about finishing and not before. This is also the place you take a close look at the edge and make sure there are no small chips or crumbling. If there are, keep going until the edge is perfect.

Hope this helps.

Ray
 

DJKELLY

Well-Known Member
What he said, over and over. I use a dmt 1200 and will not move on until I get a good hht from it. The rest always falls into place easily. Denny
 

tat2Ralfy

Well-Known Member
Same goes from me on the foundation of setting the bevel, if I know there are any chips or microchips (which I believe is what you are seeing along the very edge) I will not move on until they have gone, I use 60X and if I see any chips at that level I work at getting rid.

In both of the pictures I can see what seems to be to be microchips present, I would not be happy with either edges at either stage, more time spent on your 1200 or Coticule with slurry will rid the edge of those chips, in his second picture you can see how some of them have remained, showing the edge was not IMO ready for refining.

Regards
Ralfson (Dr)
 

jeness

Well-Known Member
The Zowada pictures are not 30x magnification, they are at 200x.

"The stone surfaces, and the razor edges are all at 200x"
 

wdwrx

Well-Known Member
well you guys are gonna think Im a real dummy... and an argumentative prick to boot, but I'm about 99.9% sure that the bevel is set. Some of these are razors that shave quite well. One of them is from Gary, Cedrick's Focus, that purdy Double Duck that arrived from Denny today. (it took me all of about 3 minutes after it arrived before I had it under the scope... shaves like a dream BTW, Thanks Denny) Everyone of them, to one degree or another, show this light reflection off the bevel tip, and have some amount of micro-chipping (if that's the appropriate word.) Sorry, I'm not trying to be argumentative. I even, today, took a razor to the DMT, 20 laps on one side, checked under the scope, and I could see the burr, 20 on the other side showed that the bur had flipped sides. 20 x-srokes and it was gone, the light reflected was reduced, and after 20 laps of slurry, the "string of beads" was back, much more noticeable, anyways. I skipped quick through dilucot to get to thin slurry stage where I slowed down, but after lots of water laps, the edge imperfections are still there.
Posting those photo was maybe not the greatest idea, they are close to what I'm seeing, but they aren't on the same scale, so at best, they are a poor approximation (next, I'll be drawing pictures and posting photos of those!) At 40x, the bevels I'm looking at appear absolutely perfect. It's only at 100x that I can see these imperfections. At that magnification, the 30x slurry edge looks more similar to my edge at 100x. If that makes any sense. If I had a bevel that looked that way at 40x, I'd definitely head back to a heavy slurry.
keep in mind, the light source I'm using is placed (pure coincedince) at about the optimum location to create this reflection; about 10[sup]o[/sup] elevation, perpendicular to the blade. If I adjust the light source, the reflections disappear completely.
The tentative conclusion I'm coming to is that what I'm seeing is the structural limit of the steel. It's such a prevalant phenomenon, so far present in every blade I've examined (including a DE blade, which was the least reflective, but still showed some) that until a better explanation comes along, i'll stick to that.
I think Janivar nailed it... just too much magnification.
 

wdwrx

Well-Known Member
jeness said:
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You're right. Sorry guys, my mistake.


I need a moment to re-evaluate... :blink:

edit:
well, all right...:)
I went back and had a look at all of Tim Zowada's photo's. Keeping in mind that those are 250x, my edge looks nothing like it. Much cruder. To be brutally honest about it. As I browse through the gallery of photos in the link Torolf posted, the one that bears the closest resembelance to the images i see in my microscope of my edges is the hard arkansas. I know the magnification is different, but it's pretty close to what I see at 100x.
this kinda bums me out. I've gotta go another 150 times further! (joking!)
This strikes me as a fruitless path though, comparing different magnifications, different lighting.

The question at the bottom of all my long-windedness is simply this:
is the pattern of light that I see refelcted off the very tip of the bevel an indicator of the refinement of the blade, and is there a technique, or practice I could try to minimize or eliminate that? And is that even possible? Or is it a function of dealing with the physical structure of the steel vs. the hone, in the real world and it would be unrealistic to expect much improvement?

At the very least, thanks for stickin' with me as I work my way through this. Considering I didn't even know what my question really was when I started this post, I've already come a ways:p

thanks guys
 

Bart

Well-Known Member
By looking with magnification, you are chasing a ghost. I'll try to explain why.

The theoretically maximum resolution of light microscopy is about 0.5 micron. That is looking in lab conditions, with the objective almost touching the object, looking trough a thin film of oil (for less light difraction).
They way we look at razor edges, though air, with larger focal distances, with not the highest end optical lenses, the resolution we get is probably larger that 1 micron. Likely considerably larger.
That means, that no matter how high your magnification the smallest detail you can see will never be smaller than 1 miron. You can blow up the picture, no problem, but it won't show you anything more. In stereoscopy, 40X is about enough to see whatever can be seen. The rest is just magnification of the same detail level.

That said the edge of a razor has a radius of about 0.5 micron. Until proven otherwise, I remain convinced, that a radius of 0.1 micron more or less than that will make a tremendous difference for the performance of the edge. After all, it does mark a 20% difference in width of the edge radius. Are we ever going to see that 0.1 micron with our light microscopes, crippled to only show us details greater than 1 micron? Nope.
On top of that, what you observe near the limits of you equipement could be light diffraction cause by the structure of the steel at the very edge. The fact that is dissapears with the smallest afjustment of the lighting sourse suggest something like that.

Optical light microscopy won't solve any of our little edge finishing mysteries. You can tell wich on of Zowada's edge bevels looks most polished, but you can't tell which one shaves best, whitout actually shaving with it.

The microscope is valuable for showing up structural damage in the steel of the razor, microcoping chipping, corrosion problems, etc. But for a razor with good steel, the microscope can't tell me anything that I can't see without it. That I have often wished it were different, doesn't change it. I've dreamed once that my wife gave me a SEM for my birthday. :D

Kind regards,
Bart.
 

vgeorge

Well-Known Member
Has anybody here shaved with a blade honed by Zowada? His approach seems a bit unique:
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. He has as many as THREE tapes at some stages of his honing progression.
 

Smythe

Well-Known Member
vgeorge said:
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Never ceases to amaze me how the so-called experts make a simple job look so bloody complicated…. Well at least suggests “only” 2 hones with an optional 3rd.

I also suspect these custom blade makers temper their blades so hard (I suppose it’s an “ego thing”) that the normal honing angle will not produce an acceptable edge (brittle, so the edge crumbles). And the solution?... increase the angle with tape or a (loose?) loom-strop filled with lapping paste.

With all the technology we have at our disposal today… it would appear the simple craftsmen of old were sensible.
 

tat2Ralfy

Well-Known Member
Chris all I can do is repeat what I have said all along "if we look at our edges with enough magnification, we would throw them all away!"...lol

Regards
Ralfson (Dr)
 

wdwrx

Well-Known Member
OK. I've quite using 100x magnification. I usually don't need to be told something more than twice... ok... sometimes three times:p . I've looked at every blade I own, and other than varying degrees of texture to the very tip of the bevel, from the worst shaver to the best, they all look pretty darn similar. At 40x, they all look freakin' perfect.

My problem is, I'm on a plataeu. I know that I have just a little ways further to go, but I don't know how to squeeze that last 10% out of my stones.
I'm all over the map when it comes to trying different things, I'm narrowing in on that "perfect edge", but short of using things like lather or oil, which both seem to have some drawbacks, I'm at a loss as to where to go from here.
Suggestions? Thoughts?
 

rayman

Well-Known Member
wdwrx said:
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Chris,
The problem here is that the last 10% you are looking for will most likely happen when you least expect it to. Step away from it for a while and take a break. Come back to it in a day or two when your hair has grown back a little...LOL

Ray
 

Woodash

Well-Known Member
I mostly use the TPT and the feel on the hone to assess where I am, but I also like magnification to know about some of the more subtle effects, particularly the effect of some treatment on the scratch pattern. Too much pressure - not enough? Slurry too dilute - too pasty? Characteristics of a new stone, effects of paste, etc. All that doesn’t (necessarily) translate to shave quality, but for me, it’s a valuable tool for certain things and a very interesting one as well.

The following are all at ~230x.

TI Carbonsong 6/8 finished on an 'intermediate' Jnat and stropped. Note hazy scratch pattern and lineation near the edge:
5283673858_ac0bb73f77.jpg

Same TI Carbonsong finished on a 'final finisher' Jnat - a very hard, very fine stone - unstropped. Much finer scratch pattern than the previous step:
5283674688_cb655beb1b.jpg

Same TI, same 'final finisher', but stropped:
5283074497_d0a0405bc7.jpg

BBW garnets, showing fairly euhedral (angular) crystal faces. The shiny, fine-grained materials are mica, aligned ~paralled to the surface. You can see dark alteration zones around most grains. Notice also the thin vein of quartz running from NE to SW and cross-cutting a garnet.
5283195030_c006f0458a.jpg

Dull, hazy quartz apparently coating the surface. Note the pseudohexagonal quartz grain at top-center-left:
5283194386_bb32b2d74e.jpg

Well, like I said, I think it's both useful and fun.
 
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