Edge study with macro photography

Gator97

Gator97

Joined
Apr 10, 2000
Messages
3,794
Hi All,
Decided to share few interesting(at least to me) findings after photographying knife edges with macro lens.
So, in the begining I got the macro lens by accident, I needed something else, wide angle lens, got macro, didn't work for what I needed, but decided to keep it, later better macro came out, 1:1 upgraded to that lens. And then added 4x magnifyer front lens to that.
So, 1:1 macro lens allows taking a picture of live size, then 4x lens in the front gives 4x magnification obviously. However that is true for print sizes... On the monitor, when you're looking at those pictures magnification is around 16x for the vertical resolution of 1200 pixels, and around 19.5 for 1024 vertical pixels. For 1024x768 resolution it'll be even greater.

Finding #0, not knife related - Macro photos at that magnification are pain in the neck, especially when you don't have copystand. So, I'll have to get that thing too.

Now, to the edges.

For starters I wanted to see what was the polished edge look alike...
Specimen #1 - Benchmade 710 HSSR, M2 steel, BC carbide coating (while BodyCote was still accepting custom orders). Original edge was V grind, and then I was using mousepad/sandpaper method so the edge is now convexed. Visually looks quite mirror polished, now check this out:

Quite messy. And For last few months I was sharpening/touching up with 5 micron abrasive film and then 0.3 micron one. I was really surprised with this one. The lighter line at the edge is the convexed part.

Next is specimen #2 - Scott Cook Lochsa, S90V steel, initially convex edge frmo Scott, then I was using the same 5 mic, and 0.3 mic abrasives. Now, this is trully mirror polished edge.

The dark, rounded line is the actual edge, reflecting camera body. Mirror polish. Visually you can tell that Lochsa has better polished edge than 710HSSR above, but the difference isn't that visible as here.

Next, I decided to see factory edges. I have a few factory knives that I have never sharpened. Well, as you can guess visually those don't look very "mirrory".
Specimen #3 - Benchmade Gaucho, now that looks rough...


And specimen #4 - Camillus CUDA Aftermath, and this one isn't looking any better:

The interesting part is that between #3 and #4, later can shave, although with some difficulties, and former is almost dull. So, the looks, even with 16 magnification can be deceiving ;)

I decided to check next factory edge, specimen #5 - Benchmade Sequel. Still looks rough, but cutting wise, it is level above #4, let alone #3.
.

Now, this is again Benchmade, specimen #6771 with CF handles. It had pretty decent edge to begin with, and then eventually became mirror polished using the same 5mic/0.3mic abrasive films, but again, hard to tell from the picture that is is actually mirror polished edge able to shave effortlessly in both directions...
.

Continued in msg. II because I can't post more pix in one msg ;)
 
After that I had to check trusty Nimravus HSSR, specimen #7, which looks like this for now after getting BC coating.
Interestingly this one ended up looking pretty smooth.
.
Which matches its sharpness.

Then was another major user, now in the kitchen, specimen #8SRKW Bog Dog, D2 steel, shaving sharp, still mirror polished edge.
.
By this time I wasn't surprised to see scratehd, toothy edge.

And final one for today, specimen #9 the old workhorse, beater, used and abused CRK Project II.

This was pretty much what I expected to see, including the dent it took from the nail a while ago. Kalgard coating looks pretty messed up but holding well.

As for the conclusions I don't have too many yet. One is for sure, magnified edges look completely different, and in 99% cases not what you'd expect to see, or at least what I expected to see.

By the way all this is not to say that rough edgers are no good. I do sharpen bunch of knives with rough edges, slices better... And even when two edges look equally rough they can be at the completely different sharpness level.

Next probably I'll take more pictures of edges in various lights and better equipment...
Bear in mind these pictures are downsized from 3504 x 2336 original size. I did crop when I could, but on the average these are 1.5 2 times smaller than the original stuff.
One thing I want to do is to sharpen a knife tomorrow to "perfect" edge and then watch its degradation and take pictures along the way, including effects of steeling (if I can make that visible on the photos) and touchups and so on. Hopefully it'll work somehow.
Other than that I am tired and not too many ideas, at least till new copystand arrives.
 
I don't know why, but these sort of pictures really fascinate me. I look forward to see the pics of an edge degrading after use.
Thanks for sharing.
 
very neat shots, nice work with the lens. what was your exspoure and backdrop material?


have you considered taking a blade from factory sharp to mirror finish and showing the steps?

I've seen similar shots done on fine swords and fine shop tools (odd pairing?).


one trick that i know of is how japanese sword blades are photographed- a sheet of glass is laid on a dark surface, the blade laid on that. the camera is fixed above the blade and a reflecting flash bounced off the sidewalls. light relects darkly through the glass plate and highlights the edges of the blade, bringing out all sorts of detail.
 
Interesting idea. I do have a tinted glass for photographic purposes :)
I'll try today if it does something, but apparently I need to wait for copystand for best results.

Once I have a copystand the rest of the stuff will be easier. And I'll definitely do the sharpening steps pix...

OBTW, there's also serrations macro photo gallery.
 
Nice work, it would be informative if you added that as a regular feature to the reviews. Then after using the knife you could start to get a feel for how the performance correlates to the image.

On a side note, when I click on the links in the above all I get are microscope thumbnails which all look the same. When I first read it I started to write you an email to ask what the hell you were getting on about because every picture looked exactly the same. White block with a black line on bottom.

I then go into thumbnail section and I get huge photo's, great detail :

http://zknives.com/images/knives/macro/edges/n_edgebm710hssr.jpg

-Cliff
 
Hiya Cliff,
Now you got me confused :) When I click on those thumbnails I do get the large image.
Can you email me exactly what's the prob? The link below should't work at all, I mean the one you posted.

As for the rest I am going to start using macro photos to the reviews. ANd I am gonna do mini study on edge degradation. I'll post new stuff as it goes.
 
Ok, after experimenting a while I managed to double magnification. Current batch is approx 32x if you have 1200 vertical pixels...

Anyway, I went sharpening few knives 2 days ago. Benchmade 710 HSSR was one of them. I resharpened, well rather touchup with 5micron abrasive film and then polished with 0.3 micron film. Again, visually it looks very polished, but not under 32x magnification.

Interestingly, this picture clearly shows convexing at the edge tip caused by sharpening on the 0.3 micron abrasive on bench strop, practically same method as the mouse sandpaper, but since it's less flexible surface gives little bit better control. Also, it is smoother compared to previous one, bear in mind the one below is 16x magnification.


Then for the kicks I took a picture of the
Global GS-2 Kitchen Utility Knife, one of my favorites in the kitchen. VG-10 steel, around 59 HRC. Now this one was sharpened in the same batch, using mousepad/sandpaper method, 220, 400 and 600 grits. Under the same 32x loks pretty smooth(well, relatively). I think the fact that 600 grit sandpaper was rather worn out contributed to that. Anyway, in the current stage this one is nowhere near mirror polish, but can shave. So, makes a good candidate for edge degradation photo study.


Next comes trusty TTKK S30V. Sharpened on edgepro first, I needed to thin down the edge. So, it's 15 deg. per side, or 30 included. Used all edgepro stones up to 3000 polishing tape, after that came 0.3 micron abrasive, and then stropping.
Abrasive film was laid on the bench strop, so it did produce tiny convex edge tip. Which is clearly visible on both magnifyed pix.
Ok, here's the pix, first the plain edge view, live size so you get the idea:

As you can see, it is morror polished and all that. Now zooms:


So, at tme moment of taking the pix of GS-1 and TTKK both were untouched after initial sharpening. I'll be using those in the kitchen and for other light cutting, which is their designation anyway and then periodically taking macro pix to monitor edge degradation and steeling/touchup effects (if any of that will be visible :))
Hopefully by that time new equipment arrives so I can take sharper pix, i.e. achieve greater magnification as well.

Full gallery with comments can be found here
 
Really nice pics there! Those are the type of views I get with my stereo microscope at about 30x (got the eyepieces and objective to get between 5x and 120x, but 30x seems really good for this sort of detail without making focusing a pain)
 
I really like seeing stuff like this. It really helps you understand whats going on.

Global don't use VG10 steel though. I'm fairly sure it's AUS118.
 
Interestign. I was sure it was VG-10. At least I do believe that's what was the word on the forums. And according to them it's high alloy vanadium blah blah. I donno about Aus 118 though. Can be that one as well.
 
Great thread Gator. Here is a D2 camp utility I did on the EdgePro with the #3000 tape.

IMG_5500.jpg



I'm pretty interested in this and started a thread a while ago about the best grit for a certain steel at a certain hardness.

I'm still interested to see how different steels perform on a given medium assuming they all have the same geometry and profile. It would be very time consuming, not to mention expensive, but I think the results would benefit the knife community a great deal.
 
Very nice pictures. Have you tried looking at both sides of the edge? I noticed that on some factory edges that look very rough, the very edge of the bevel is polished, but only on one side. The new Caly Jr. came like that.
 
Yeah, for my blades I try. Unless I see a difference under magnification I won't post it, but for at least some of the lades I have both sides I think.
 
You must log in or register to reply here.
Back
Top