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I wish someone with a collection of stones, would polish small bit of mild steel so we can compare fineness, between natural and synthetic.

That would be great to see.
Or define the exact rules/procedure (type of steel, geometry, progression etc.) as well as results presentation method, and collect results from various contributors...
I've got some stones and wish to contribute, but to get comparable results we need to have very precise rules
 
That would be great to see.
Or define the exact rules/procedure (type of steel, geometry, progression etc.) as well as results presentation method, and collect results from various contributors...
I've got some stones and wish to contribute, but to get comparable results we need to have very precise rules
good idea, don't think it would be too demanding, mild steel is so soft.
 

Steve56

Ask me about shaving naked!
Yes, a lot of natural stones don’t make polished finishes. It might be worth a shot with synths, mostly to see if there is coarse grit present, but even if there is, it doesn’t (usually) affect the shaving edge. Shapton Pros leave more coarser scratches than the Glass Stones, but there’s not any difference in the practical results.

A lot of us have looked at a lot of bevels over the years/decades. Get Shapton Glass or Naniwa Chosera (and be prepared for the finer Chosera to crack).

A good razor hone has:

A narrow grit distribution, no coarse grit
A grit at least close to its rated grit
Enough hardness where it doesn’t slurry a lot

A bad razor hone has:

A wide grit distribution
A grit that may or may not act like its rated grit
Too much softness, muddy

Knife people like soft hones and a wider grit distribution doesn’t matter that much. A pot roast never complains. Razor people need harder stones with less coarse grit below the rated grit.

Needless to say, quality razor hones with the ‘good hone’ attributes, are and always have been expensive. It just comes with the requirements making a quality razor edge. If you can’t afford a good quality razor hone, go with film and pastes.
 
I've learned a lot about my hones by obsessing about my sushi knife bevels and edges. Regularity, shine, contrast and sharpness.

The single traditional bevel, mixing steels and hardness, is very wide, and sits flat on the hone. The edge is almost as hard as a razor.

It helps me to see how the hones interact with the steel. How regular and fine are the scratches, how refined is the surface finish.

It doesn't tell if a hone is good for razors, but how those identified as good hones can compare, and to help to find the best way to use them.

And when I'm done playing, to get the absolute best slices of fish I've ever cut. Some of the edges I get fall trough fish like no artificial edge I've tried. So smooth and effortless, like shaving...
 
Anyone up for that :)
Funny, I had the same idea. Not from a polishing point of view, but because I wanted a better understanding of the relative scratch fineness of some of my JNats, and scratch depth, especially among different lines of synthetics. The vision was a bunch of labeled pieces of steel with scratches from my various stones, that I could consult, under the microscope, to get a preview of what the stone does.

The project is not going well so far, but I am not giving up.

First I tried feeler gauges, but the steel is pretty impervious and annoying for the purpose.

Then I got some anodized but not heat treated knife blanks, planning to cut them into pieces and make marked pieces of steel.

It turns out that my stones are a lot flatter than these knife blanks, so they only affected a small area. I put them aside in frustration, and put them aside to think for a while, but it occurs to me, writing this, that a small polished area might be perfectly sufficient for my purpose.
 
The.highest polish would be available from using lapping film imo. It.is.made for polishing glass among many other things. And the grits available up to 1/10 micron grit. I've used this uber.fine film to hone my razors and I hated it. 😁
 
As already mentioned, mild steel will be no good. You'd want to use something similar in composition and hardness to a razor. So maybe O-1 or 1095 would be good. Probably blanks with similar surface area as a razor bevel. And they need to be hardened. It will be difficult to compare between images from different individuals, since these would need to be imaged under a microscope. The position of the blanks and the position and intensity of the lighting would have to be identical to produce useful comparison images.
 
When I get a new to me hone I use the back of a chisel to get an idea of what I'm working with. I keep a 2" beater chisel around for just that purpose. It will give me some indication of the speed and scratch pattern.
It's a long way from anything scientific. Down and dirty quick look.
 
I may take a small crack at something like this soon. I will probably use a single razor and try a series of a couple different images for each stone/hone. One focusing on bevel scratches and one focusing on the apex. I just fell into another somewhat older scope that was a powerhouse for metallurgical examination that should be perfect.

Resized_20210724_090342(1).jpg
 
The big difficulty here is that the effect of the bind has an extraordinarily large influence. And scratch patterns may not mean much at all - you do need to look at the edge.

This picture is a slightly rudimentary example cos I only did it for a minute, but it shows polishing on a hardened, mono-steel kitchen knife. The section at the top is from an Ouka/Cerax 3k, the bottom near-mirror section is a Naniwa SS 3k. The Ouka is an infinitely better stone.

Screen Shot 2021-07-26 at 3.46.11 AM.png
 
Yes the apex is more important, but everyone always wants to see the scratch pattern, you know how that goes... It's relevant for things like large knife bevels anyway. Not so much for a razor.

This scope has brightfield, darkfield, polarization and DIC, so it will be interesting. All are reflected light or EPI - so the illumination goes through the objective lens itself. That should make for pretty uniform and repeatable lighting. I am just going to do it for my own enjoyment but I'll share for anyone who might be interested.

For apex examination I have actually gotten some pretty decent results with a regular old biological microscope using built-in bottom illumination, backlighting the apex and providing a very clear view of the silhouette of the edge, like the attached. It is a little finicky to get the adjustment of condenser position and aperture just right, but works quite well.

20210520_002249.jpg
 
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Yes the apex is more important, but everyone always wants to see the scratch pattern, you know how that goes... It's relevant for things like large knife bevels anyway. Not so much for a razor.

This scope has brightfield, darkfield, polarization and DIC, so it will be interesting. All are reflected light or EPI - so the illumination goes through the objective lens itself. That should make for pretty uniform and repeatable lighting. I am just going to do it for my own enjoyment but I'll share for anyone who might be interested.

For apex examination I have actually gotten some pretty decent results with a regular old biological microscope using built-in bottom illumination, backlighting the apex and providing a very clear view of the silhouette of the edge, like the attached. It is a little finicky to get the adjustment of condenser position and aperture just right, but works quite well.

View attachment 1301983
Ha, yes indeed! The thing with the bevel on that knife was somewhat weird, and slightly annoying as I was trying to put a hazy stone finish on it. I finished on the Ouka and then went to the Naniwa which then just polished out all of the finish I'd put on, so I had to re-do the Ouka. I have much finer stones that do nice haze/kasumi, but learned after that the SS series is apparently known for doing this. In a way it's quite an interesting thing to have though - if you want a mirror finish off a jnat you're spending big bucks on a very fine and hard stone.

Definitely interested to see some of your results here. And doing with a SR makes a lot more sense I think than doing with a knife... I'm pretty good at freehand sharpening a kitchen knife, but there would still be a load of variables that are going to be impossible to completely accurately control, to do with angles and pressure, that should be a lot easier on a razor I imagine (?)

Anyway... looking forward to seeing the outcomes!
 
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