Got the scope out again.

[eKretz]

Yeah it's a pain to get high quality micrographs without high $$$. BTW after your comments I just double-checked on my monitor with pixels 1:1 and my images are indeed at 239.6x with the capture set to 1MP (1280 x 960 - this is how I usually take them). The camera can capture from 1MP to 5MP. Perhaps the resizing from the board software is hurting them, I haven't checked to see what they're resized to after posting. I've been looking into getting a better setup - watching Craigslist like a hawk, haha.

Edit: just checked and the photos are getting shrunk - resized to 800 x 600 by board software.

 

[spoken36]

Amen, brother. There's a big difference between trying like a bulldog to maintain one's position, versus being humble enough to seek the truth that is out there. The former is worthless, debate-team crap, and the latter is golden.

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.

 

[SliceOfLife]

I've got great news for you, and not so good news for you.

Great news. Your theory is absolutely correct. I have photographic evidence of it.

Bad news. This damage is MUUUUUUCH worse when backhoning (spine first) vs standard honing (3-4x worse).

Slightly worse news. This razor was an eBay special that was almost pitted through and then horridly restored by someone with a buffer and not enough experience using a buffer before being sold in a lot I bought for a stone. The metal is basically the equivalent of steel poop. I don't think it's reflective of standard behavior, since it's the first time I've seen anything like this in oh... maybe 500-1000 restores on this particular DMT.

Kinda meh news. It's not an 8k, or a 320. It's a 600 and 1200.

Good news. It does seem almost exclusive to diamond plates, at least. No signs of this damage off my King or a Washita, so there is definitely some kind of flex happening at the edge during honing due to the nature of the plates... keeping in mind this evidence has appeared on exactly one (extremely badly damaged) razor in the history of my honing.

Bad news. Now I have to grind away at this razor and see if I can ever get it back into good steel again, because I'm too stubborn to just trash it.

Really good news. This actually does cause EXACTLY the kind of tearing that the fellow with the SEM theorized. And it leaves edges that look a freaking LOT like the edges he imaged. So it would appear exactly what he theorized is happening, but again: This is literally the first razor I've EVER seen this happening on. Generally razors this badly damaged go right in the trash. I was stubbornly trying to save this one because the seller sent me so many crap razors in the lot but it wasn't enough money to bother complaining about since it was international and the shipping was half the cost (others were cracked, etc; seller said they were all in great cond... basically overpaid for the stone expecting the razors to be able to make up the difference).

 

[Devonmoonshire]

Weepers and Nicks and Gouges Oh My!! I say tap your heels together and hustle back to Kansas on that one my Friend

 

[eKretz]

Nice! I wonder if maybe it's more likely with certain steels or hardnesses? I've only tried it on the one razor, an old beat-up Sheffield (like most, I don't want to take a coarse diamond plate to a very nice razor either). Those pics look pretty darn close to what mine were showing.

 

[SliceOfLife]

Yeah, this is also "a beat up old sheffield".

Find a nice cheap american steel razor from the early 20th century to try. They come up real cheap on eBay often and their steel is HARDY and responds as beautifully as anything to diamonds, Cuts are clean as could be. Let me know if you see any of the same. I've had no problems with sheffield steel before this one either of course, but in general I feel it's one of the more "sensitive" steels to technique. The american steel usually is a workhorse steel it's hard to hone wrong, and the older german's are my favorite, they have an almost artistic flow that even seems to cover up mistakes. The more recent (many of the tourist 7 day sets and similar) germans lean much more into the british steel territory, but lesser quality. The exceptions being higher end models (some more recent Puma's and Hencks I own being good examples), that move more towards the american steel (a bit less of a flow to them, but not the quality drop of the cheaper models).

 

[eKretz]

Definitely going to have to try it on another razor now. I've got 10 or 12 razors ATM, but none I want to take an edge off of right now. I'll grab one from eBay ASAP to try it out and post results here. The fact that yours was a Sheffield as well lends some credence to the theory that certain steels/hardnesses will be more apt to display this behavior.

 

[SliceOfLife]

I'll snap some shots of another sheffield that doesn't do this, probably tomorrow. I'll try to match the edge angle too (14.3*), or at least get as close as I can. That's a pretty low angle for a sheffield as well, so it may not be possible. (Not sure if I have any other <15* sheffs around here atm). The low angle is possibly due to the restoration.
I think I've got a 13.1* or so American around here somewhere. I'll get a few shots of it too, to show that low angles don't create this problem as long as the steel is suitable.

I hope my camera mount gets here tomorrow, though, as I'm hoverhanding my camera over my scope to take these shots, and it's a really tedious business.

 

[SliceOfLife]

Oh damn, I have a 12.7* sheffield sitting right here from another lot that seems to be in good shape, but I haven't honed yet. This is perfect. It's a "Vulcan" by Thomas Ellin & Co. I bought for the Ivo scales, that's actually in pretty decent shape. I'll get some pics up asap.

 

[SliceOfLife]

Fresh off a 30 second run on the DMT's. Steel as straight as you could want.

It's not perfect, as there's a bit of rust hanging around I need to hone past, but if anything changes, I'll let you know.

<13* angle sheffield


edit: Oh, yeah definitely some bad micropitting up near the toe that I need to hone past, but the steel is good. Takes a bullet straight edge, no wave, breaks, or signs of flexing at all. I'm gonna take a solid mm off the first razor (It's a William Morton), and bring it up to 15.25* or so, see if I can't get it to take a proper edge tomorrow. Hopefully the steel isn't junked all the way through.

What's the process used to put his cuts in the razors for imaging? I wonder if it doesn't possibly affect the integrity of the steel and cause him to get these results.

 

[stoop]

Wow. I wonder if there is some kind of lack of ductility or brittleness that made the first one break off like that?

 

[SliceOfLife]

No luck. Ground a half mm off it. Fully rebeveled. Still acts exactly the same. Steel is trashed completely. Gonna steal the scales off it and toss it.

As for the specific reasons why, I'm not really sure. Usually garbage steel (like pakistan razors) has a very evident feel on the stones. This one doesn't feel right, but it doesn't feel like they do (they feel what I'd call too hard/brittle usually). It feels more like it's kind of just riding around on the abrasives, and the sound it makes has a nasally, hissy note to it. Definitely something wrong with it, just a lot less noticeable than trashed steel usually is.


I'm thinking I'll give it a try on other stones, bypassing the DMT's and see if it gets shaveable that way; but in my experience with other trashed steel razors, even if it'll take an edge up to 12k, the edge will just break up into a wierd wavy mess after the first use. That's my prediction here.

 

[SliceOfLife]

"shave ready"

Washita bevel
Full dilucot honed

I looked at maybe 1/3 of the edge, and this (pic 1) was the only evidence of the folding I could find at the end of this progression (no DMT use), but the tearing of the edge is, as you can see (pic 2), just as bad. Probably having loose grit, slurry, etc; causes the edge to slough the fatigued bits off more readily, making it harder to catch the bent but not broken bits, vs the DMT having no free grit leaving it much more difficult to see.

edit: Added a second image of the "fold" with a key for sizing/magnification check. On my monitor this is ~1kx

 

[SliceOfLife]

Here's a Clauss @ 8k DMT finish at similar mag. Key should actually be around 3.5-3.7um, but I rounded up. Again, about 1kx on my screen. Razor is the same as a USMC model, minus the stamp. So, 1920-1930ish American steel, 6/8" and around 15.7* grind.

 

[stoop]

Are you certain about the scale there? That's a remarkably even finish on the bottom one if that scale is correct, even for a very fine edge, much less an 8k. It's implying edge deviations of only a couple hundred nanometers at the most. That seems incredible to me for an 8k finish- the particles are larger than a micron.

 

[eKretz]

The Pakistan steel that gives the funny feel is due to them not being careful enough with their alloys I think - resulting in a lot of carbides forming. Which makes honing considerably more of a pain than with good pure plain carbon steel.

Regarding the edge being very straight from the DMT 8k above - that could be that effect with diamond again. Even the edge I got from the 325 was incredibly straight - for a 325.

I just checked my test razor and the angle ranges from about 18.5° nearer the heel to 19.5° nearer the toe. This one hones relatively well with no odd noise or feel, but it might be a bit on the soft side.

 

[147_Grain]

What's the process used to put his cuts in the razors for imaging? I wonder if it doesn't possibly affect the integrity of the steel and cause him to get these results.

He uses a focused ion beam for sectioning. It's really precise (used by semiconductor fabs to cut connections, the beam width is in the tens of angstroms) and the other sections he's done on razors not honed this way don't show the same weird flakiness near the apex, so I don't think it's the FIB that's causing this.

 

[SliceOfLife]

Are you certain about the scale there? That's a remarkably even finish on the bottom one if that scale is correct, even for a very fine edge, much less an 8k. It's implying edge deviations of only a couple hundred nanometers at the most. That seems incredible to me for an 8k finish- the particles are larger than a micron.

Yes. The image is optically magnified to 400x, the FOV is measured, recalculated for the camera trim, then the key is calculated against the remaining FOV. The Key is accurate bearing in mind hand taken measurements at the last step (so maybe 90% accurate, we'll say).

As Ekretz points out, DMT's leave very straight edges, though thick. Hence the broad area of reflection at the apex. (Due to light source being directed at the edge itself) This is really only noticeable for me on the higher stones (F and up), though I don't use the lower ones much for razors. With the EF and EE both showing edges that compare with 10k+ JIS stones in everything except edge radius. This is why I like using them. They require finishers to thin the edge radius, but NOT to clean up damage to the edge the way many other hones at this range do. A 4k King or 8k Norton leaves a ton more work to do to get a clean edge off a very fine finisher, as the edge must be recessed significantly to remove damage left. The DMT bypasses this problem, as finishers are much, much more capable of reducing edge radius in very few passes, vs recessing the entire edge. This allows extremely clean and smooth edges off high quality finishers, and brings out the drawbacks of lower quality finishers (finishers which themselves create significant edge damage).

This is why I'm so certain that the other images have some form of variable that is out of whack. Because they demonstrate EXACTLY the problem that I avoid from other finishers by using the stones he's encountering the problem on. The very reason I use the DMT 8k is that it is uniquely capable of avoiding the damage he's blaming it for. Every other stone I've used anywhere near this grit produces much much more tear in the edge vs the DMT 8k. The DMT 8k unquestionably after seven? years of using it daily on razors leaves the least torn edge of any hone in its range.

 

[SliceOfLife]

Also worth noting is that my own theory is somewhat similar to eKretz's with a very important distinction.

He believes plastic deformation occurs at the edge, creating a micro-burr, which is removed creating a compound edge.

I believe elastic deformation occurs at the edge, shallowing the cuts at the edge, with a very gradual increase in cut depth as you move back. (This is not exclusive to DMT's but they demonstrate it to the greatest extent I've seen.) Not sufficient to create a hollowed bevel (which would be a huge problem), but sufficient to explain the way the polish increases in the bevel as you move towards the edge (pretty obvious in that last picture), as well as the relatively high thickness of the edge and extreme straightness of the edge for the grit. This also explains why excessive pressure can create the torn edge, as you push the bevel into the stone behind the edge, you move it to the point where the bevel IS hollowed behind the edge, causing massive edge failure. Essentially with excessive pressure, you create a false edge behind the real edge, and hone until the edge joins at points, creating failure of the true edge, and thusly the massive gaps, such as those seen in the SEM images.

 

[SliceOfLife]

My new mount arrived. So For reference.

Here is a SP 13k (somewhere between .7 and 1 um avg prtcl size iirc)
A DMT 8k
And a Russian Barbers Synth I just bought



That big gap towards the top of image in the 13k is probably razor-based, not hone based. Razor still has a spot or two of pitting near the edge and that seems out of place, so I suspect I may have caught a shallow pit there and had a failure.

Gonna try and rotate the mount and get pictures oriented so the scale can be up a bit more in the future, but it's tricky enough to get it to focus as is, so this will have to do for the moment. Actually, my camera may be able to take landscapes at 5MP, if so it's an easy fix.