Got the scope out again.

The problem is your theory has no evidence to back it up. It relies exclusively on being able to roughly explain away results a single tester has managed to attain. Todd himself later tests and admits his 1.2k and 8k plates are defective. Though it's unlikely these defects alone explain the results he's getting. What does explain his results is, as I demonstrated, exactly what I theorized. Excessive pressure on the 8k plate causes the edge to tear giving results that are identical under magnification to what he presents as a properly honed edge.

Anyone and everyone with these diamond plates can easily confirm that every edge cuts better coming off the 8k vs the 325 grit with proper use. There are literally tens of thousands of users out there and probably an equal number of discussions on the matter across all manner of knife, woodworking, and razor forums that flat out contradict his results. It doesn't matter how many times he tests his diamond plates if the variable of the user remains constant, and when that variable is removed his results become statistically insignificant.

You're misrepresenting my point. Yes, unpolished steel pressed together and scraped on another piece of steel will abrade. That's obvious. How it is not like a rasp is that it will not remove the surface of the alternate piece of steel in the minimal amount of space in which contact is maintained before the steel against the DMT plate would be removed by the diamonds. The Steel exerts pressure almost exclusively downward against the nickle, not in the direction of motion, as it is not being pressed sufficiently to notably penetrate an almost flat surface of nickle. Unlike the fine diamonds penetrating at points in the steel, the steel and nickle contact covers almost the total surface area of the honewear on the tool, with the diamonds maintaining contact at every other point. You go from a small percentage of the steel exerting force, to the entirety of it, so yes you will spontaneously go from the diamonds penetrating the steel (as is their function), to the nickle seeing very little deformation, and instead deflecting the flexible, thin, edge. You can force the steel to penetrate the nickle with sufficient downward pressure on the spine of course, but again that requires ludicrously poor technique, and would likely only be seen by an amateur attempting heavy grinding on something, and even then would require massive amounts of pressure relative to what is used typically while honing.

Perhaps more importantly, scratching the nickle substrate is not going to do what you expect. Yes, it will remove diamonds, at a very, very slow rate. It requires a scratch that continues until it contacts the diamond or close enough to it the binding loses structural integrity. Compound this many times across a plate, and this use does in fact significantly reduce the life of the plate. This is one of the reasons why DMT says not to use plates like this. What it does not do and will not do until the plate is virtually dead from lack of diamonds anyway, is scrape away the nickle plating upon its contact with steel as you suggested. If you magnify an old DMT, you will see scuffing on the nickle plating that is obviously not cutting from diamonds. With sufficient use, the nickle will actually take on a matte "polish", where low points remain low, and higher plateaus of nickle exist where repetitive abrasion has occurred. You will with use actually very slightly recess the nickle where the steel must be forced to contact the plate. I can literally look through a loupe at multiple DMT's, both my own and others and see where this process has happened. I speak as though it is fact because I see it in practice on dozens of plates. It's not a theory for me because it's physically in my hands when I pick up any of about two dozen DMT's at my job.


Pictured is a 325 grit finish, jumped to 8k, then to finisher. Manages a quite good shave, with the "tugging" on the WTG pass that evidences a toothy edge, but smooth performance and closeness on XTG and ATG passes of a highly polished bevel and thin edge. Again, suggesting that the 325 simply leaves an excessively toothy edge, with a high level of polish and thinness relative to its grit. Impressive that an edge in such poor visual condition performs so admirably, but it is unquestionably inferior to an edge without this "tooth" in applications that are not served by a toothy edge, namely shaving.

What do you do at work that they have dozens of DMT plates?!

As far as the rest of this goes, I think we have probably beaten the horse enough. We won't be able to come to any definitive conclusions/answers one way or the other regarding this without some proper scientific testing, which neither of us has the equipment (or probably the time) to do the right way. Anything that isn't a proven fact through scientific method is theory, IMO. Give a hundred guys your diamond plates and a loupe and you'll likely get nearly as many explanations of what is going on with the surface and why they believe so.

I took a few photos the other day, and I included one photo using my microscope of my son's hair which I believe averages in the 100 micron range. This gives my photos some scale to view from. Taking a photo of a hair is just as easy as taking one of a blades edge. Try it sometime. I have also added some captions to my photos.

Alex

Nice shots Alex. I'll throw in some photos of some DMT-finished edges (both 325C and 8kEEF) ASAP to compare to Todd's and Ian's.

Interesting pictures Alex

I just did another razor with this "impossible" method and had another DFS. This time Ian, since you specifically asked for this I took the edge back to the Chosera 1k until a foil/burr was visibly produced, then removed it and then went to my well-worn DMT C. I did probably around a hundred very light laps on the DMT C, stropped on clean leather and shaved. Again got a visibly polished apex with pretty clear convexing. Very straight edge, easily passed HHT3 no problem post-stropping and shaved great. I did one pass WTG, one pass ATG. No weepers, but got a little burn from the alum block - about 3/10 I'd say.

I took a full course of images under the scope and will post them when I can - hopefully in the next day or two, my internet is still not optimal, uploads take ages. There is definitely some strange mechanism going on due almost certainly to the large abrasive particles and their dull contact surfaces, which is why Todd's theory makes perfect sense to me. The photos will show you what I mean, but they aren't as good as Todd's or Alex's because my scope isn't a very high quality one. I'm having trouble imaging edges with the darkfield style method very well, getting a lot of blowout on bright surfaces that I never did in the past for some reason.

The images show what almost seems to be a micro convex that almost looks like it leads into a wire or foil - but it isn't one. I ran the edge along a wooden block after shaving and it didn't move a bit. The images were most interesting to see. That's why I like Todd's SEM ability to section the blade so what is really happening can be observed.

For diamond plates, all I have is the DMT 10"x4" interrupted set (DuoSharp, I think). They work ok for grinding blades in bad shape, and they flatten stones alright, but I notice an induced pattern of contact between the stone and razor right off flattening. I suspect that this is NOT ideal.

Do you consider the interrupted type to be completely different and outside of consideration in the context of the discussion at hand?

No idea. I don't have any interupted-surface plates myself. If they are truly flat, I'd imagine it should still work, but if not, the local points of contact might not allow very light pressure to be used as well. The one requirement that is certain I think is that the plate is well-worn/broken-in. Mine has seen years of use and the diamonds hardly take anything off without some little bit of pressure. At weight of the blade or lighter I don't see any swarf accumulating hardly at all when using this method on the razor. Add a little pressure (pencil eraser level) and it starts to rip off the steel immediately.

Here are a first few images. The hair Alex requested and some images from bevel setting on the Chosera 1k.

As you can see, a foil was raised and removed.

Scale is graduated in 0.5mm per line:



0.1mm diameter hair:



Foil/wire raised on Chosera 1k:



Foil/wire removed, bevel set finished on Chosera 1k:

Okay, here is the second batch, thanks to WiFi at my doctor's office.

First, my DMT C diamond plate that's well-worn after years of use, but still looks brand new for the most part:



Then, the weird, almost foil looking arising at the edge from one side:



And from the opposite side, showing the same effect that appears to be symmetrical:



Next we have a shot lit in such a way to show the slight edge convexing:



And here is the edge lit shot, which looks extremely straight and finely afforded considering it was honed on a 325-grit stone.

Oops, just noticed that one of my photos above is wrong. The two that are supposed to be from opposing sides are quite apparently not, as the scratches aren't reversed. Must have mislabeled during renaming. Anyways, they do look just the same from the opposite side. I'll see if I can fix that later. In the meantime, here's my last shot, taken with ring light:



BTW Alex, your lens combination on your scope may be 315x but your images are coming across at considerably higher magnification - probably due to your camera taking images at additional effective magnification. Anyone who wonders what actual magnification is when they're viewing can simply measure the item on their screen and divide by the given actual size - on my phone screen for instance, Alex's .004" hair measures about .80" - giving an effective magnification of about 200x. On my laptop his magnification is closer to 600x or 800x, I forget. Ian, can you post an image of a hair from your head also?

After some further looking at all the images, I think the areas in the two images after the image of the diamond plate that almost look like a bulge or a foil edge are just a trick of the light. I think it's just that the areas that appear black a bit behind the apex are highly reflective and not an actual bulge or bend. The convexing appears to be taking place in the last 6-8 microns of the bevel.

Oh, and regarding the images from Todd showing the 8k edge that is not very straight - it's quite possible that he zeroed in on an area with damage from some of the coarser diamonds that contaminate the plates. This is not a defective plate - every plate I've seen has had this - mine included. The vast majority of the honed surface is very clean, but the larger particles in the 8k plate, as well as the particles that stick up a little higher than the average cause deep scratches that are visible even when viewing with the naked eye at the right angle as they stand out against the otherwise highly polished surface. These plates aren't perfect, but they aren't defective. I also did some playing with my 8k, and was unable to get any edge damage showing ripped out chunks from the edge even with what I would consider very excessive pressure.

eKretz said:

What do you do at work that they have dozens of DMT plates?!

Click to expand...

A professional kitchen with dozens of chefs. We all own our own stones, and DMT plates are popular. You can re-edge a chipped rental in a matter of seconds. I don't think I've seen an atoma, probably due to lower availability or higher cost. A few guys use low grit whetstones (I've seen a shun branded 1k or two), but these guys tend to just borrow a DMT when they need to do any real work, or else dig out the houses old Crystolon Trihone. I could go to any of three places I moonlight and not use the same DMT every day for a month without any trouble. Hell, I could probably find a half dozen guys who could loan me theirs at my weekly card game.

My slides are dusty as hell, but here's an old hair from my brush.


Ekretz, based on your FOV, your scope is likely closer to 120x, rather than 240x. The edge looks fine for a 325 grit finish, but you couldn't pay me to shave off it. Your face is made of tougher stuff than mine.


As you point out actual magnification is entirely dependant on pixel size of your monitor and any after-effect sizing done by the computer/software. For instance, this image of my hair on MY screen is closer to 1000x, hence why it looks like crap. 400x on my screen would be an ~3x2" image.

As for every DMT having this. Mine doesn't. I've inspected Dozens, maybe hundreds of razor edges end to end coming off my 8k. No chips @ 400x, much less 100x. Hell, I've done it even more frequently off the 1.2k (it's almost habit, looking for microchipping due to pitting on eBay specials before progressing), and again, without finding pitting, there's never any issue. Maybe my 8k (and the two 1.2k's I've owned) are the creme de la creme of DMT's, but I suspect either you and he just got duds, or something else is as fault here.

Measuring on my own screen from the scope, my photos are at 240x - 239.6x if you want to be exact. As I said, on other people's screens they will need to measure to see what it is since everyone has different monitor size, as well as these photos being resized by the board software when they're uploaded.

Is that hair photo out of focus? Or is the resolution not so good on the scope?

On the DMT "damage" - my plate doesn't leave big gouges like Todd's either nowadays, but it's had a considerable bit more use than his also. When it was newer it did do quite a bit of similar damage with random deep scratches.

I wanted to take a moment and thank both of you guys - this thread has been a very interesting read and despite having opposite opinions, you two have kept this remarkably civil.

The scope is pure optical. The objectives are Meiji's. Not the highest grade glass, but pretty good. It's hard to accurately resolve and digitally capture something with as much depth as a hair with the lighting setup I have. It'd be much easier if I had a light ring. With my current setup I'd have to bisect the hair to get the entire 2d representation of it in focus. We're talking a change in depth in the tens of microns between the in focus section of the hair (the middle) and the outer regions.

The important thing, though is that the camera is only capturing @ 400x in my image, and at ~120x in your image. As Futurama pointed out, zooming in only increases the size of the image display, it doesn't actually increase the amount of detail available. No additional details are visible because my monitor zooms my image up to 1k or yours to 240. In fact in images like your last one in post #70 , it is likely creating artifacts that weren't there in the original image. It's simply expanding 1 pixel into two or three. The details present are captured at a magnification of ~120x and 400x.



Here is an image captured at 400x @ 352x288 Note the FOV relative to the hair. This is an accurate way of calculating the magnification capability of the scope. I could blow this image up and project it on the side of a building, it would still only be an accurate magnification of 400x. Further magnification would always introduce false data to the image.

I personally don't mind disagreements. If I get proven wrong then I've learned something, and that is far more valuable to me than being right all the time. I don't really understand why people get all violently caught up in defending their ideas sometimes, heh.

Ian, do you have any photo editing software? You should try focus stacking. That hair image is at least better than the first one. My scope captures directly at 5MP, not as low as 352 x 188. The optics are cheap crap though, no question.

It probably wouldn't help enough to be worth the trouble. The reason the second image is clearer is I removed the slide cover. That's how bad my lighting setup is for capturing objects like this. I set it up purely for looking at edges in real time. A few tweaks let it produce passable edge stills. Still captures of curved objects is about as far away from its capabilities as you can get. A better camera would certainly help as well, It actually scales down my images. For instance, that image right there is optically magnified to 400x, then digitally reduced to around 300x on my monitor.