Ranking of Steels by how sharp they can get?

[TheOne45]

I'm not saying it's not possible or even far fetched, just not sure what the point is of going to that much trouble to avoid a burr.

There is no point almost in any thing we do here ....
from going through 5 or 6 exotic expensive stones and 3 or 4 strops to polish the edge on exotic japanese knives
to
edge retention hysteria searching for most exotic powder steel with as high as possible vanadium and tungsten content
and to
trying to achieve so sharp edge it will cut you just standing close to the knife.

If you go back to basics and the purpose having a knife .... all we need is a knife made of reasonable steel with reasonable edge so we can cut something.

But; this is a hobby so there is no point looking for a point. You won't find a rational explanation for most things people do around here with their knives and edges.

 

[chalby]

There is no point almost in any thing we do here ....
from going through 5 or 6 exotic expensive stones and 3 or 4 strops to polish the edge on exotic japanese knives
to
edge retention hysteria searching for most exotic powder steel with as high as possible vanadium and tungsten content
and to
trying to achieve so sharp edge it will cut you just standing close to the knife.

If you go back to basics and the purpose having a knife .... all we need is a knife made of reasonable steel with reasonable edge so we can cut something.

But; this is a hobby so there is no point looking for a point. You won't find a rational explanation for most things people do around here with their knives and edges.

But there is a point to most of those things. Using a powder steel has obvious benefits in specific uses; optimizing an edge for better sharpness and edge holding has obvious benefits. Anyway as I said each to their own, do what makes you happy. Nobody is right or wrong.

 

[knifeism]

For eyeball surgery, doctors use obsidian scalpels (made of volcanic glass).

I bought one here: https://www.finescience.com/en-US/Products/Scalpels-Blades/Micro-Knives/Obsidian-Scalpels/10110-03

The Aztecs made their weapons out of it, sliced legs off with one chop.

 

[TheOne45]

Nobody is right or wrong.

Exactly.
The purpose of hobby is to do what makes you happy.

Using a powder steel has obvious benefits in specific uses

Yes indeed. Let's say for a person who needs to cut a few hundred feet of industrial cardboard of double thickness each day there is benefit in knife with as good edge retention as you can get.
For me as an average user who cuts a zip tie or a package box once in a while, K110 steel on my EDC works fine. I don't mind to sharpen my EDC when needed.
If I'm not mistaken those hi-end Japanese knives are hand-made of carbon steel. I guess they would switch to Maxamet or Bohler S290 if they would see some benefits.

 

[Cementite]

I find this extremely unlikely.

So do I.

10 microns is about 1/10 of the thickness of a sheet of copy paper. Or 1/3 the diameter of a single white blood cell. Or between 1/5 and 1/18 the diameter of a single human hair.
Got a scanning, tunnelling electron microscope?

10 microns is also for amateurs. I'm not satisfied until I get my apexes down to about half a Planck length or so...

 

[TheOne45]

10 microns is about 1/10 of the thickness of a sheet of copy paper.

Yay, at least someone over sea knows what a micron is.
A sheet of print paper is about 0.1 milimeters thick. Would that be about 3.9 thau?
So, yes, 10 microns is 1/10 of that thickness.
Huh, does that mean a sheet of print paper is 100 microns thich?

Planck length? I'm impressed.
I wonder what fancy japan stones are you using. I bet water stones are not fine enough. You would need Bingle oil stones.
Hmm, but..... what happened to nanometers and angstroms?
I know, I know.... just for amateurs.

 

[yepimonfire]

Is there a ranking of steels based on their potential sharpness, assuming all other factors are equal?

I'll take an anecdotal stab at it, from worst to best, only steels I have ample experience sharpening and using.

D2
Maxamet
S30V
8cr13mov/AUS 8
S90V
10v
M4
K390
Cruwear
Rex 45
4v.

Commentary on my rankings:
D2 and Maxamet get the lowest ranking because they only perform well with a working edge, same with S30V, if you try to get that extra level of hair whittling edge it glasses over quickly following use, everything from 10v on will take a screaming sharp fine edge that will cut hand held paper towels, some of the sharpest edges I've ever achieved were done on rex 45 and 4v.

 

[Ilikesharpstuff]

It is not an apples to apples comparison as he was flat-lapping a chunk of metal rather than cutting a bevel, but Todd Simpson tested material removal rate of some common sharpening abrasives. At the rates he achieved removing ten microns of material would take hundreds of strokes. One can expect the higher pressure in bevel cutting to be faster, but the idea of "sneaking up" on a nascent apex is not really far fetched.

Seems like fine electroplated diamond plates are taking off the most material per 100 strokes other than the Sigma 220...am I reading that right?

Is it fair to assume this is because of the phenomenon described by Science of Sharp where finer grit diamonds make deeper scratches than coarser ones?

By this logic should we be roughing in bevels/establishing an apex with fine plates when using electroplated diamonds? I might have to do some experimenting with my TSPROF F1000 and see what happens vs. the F150

 

[Mr.Wizard]

Seems like fine electroplated diamond plates are taking off the most material per 100 strokes other than the Sigma 220...am I reading that right?

I believe you are reading that correctly, but you must not overlook the parameters of the experiment, nor his conclusion:

"The force and surface area were chosen to be in the typical range used for honing a straight razor."

"Coarse stones are only faster if sufficient pressure is used. ... There is a critical pressure required for an abrasive to cut into the workpiece, otherwise it will simply slide without removing metal."

 

[Ilikesharpstuff]

I believe you are reading that correctly, but you must not overlook the parameters of the experiment, nor his conclusion:

"The force and surface area were chosen to be in the typical range used for honing a straight razor."

"Coarse stones are only faster if sufficient pressure is used. ... There is a critical pressure required for an abrasive to cut into the workpiece, otherwise it will simply slide without removing metal."

Initially I don't see how those two statements change much about what I'm curious about, but I don't know anything about honing a straight razor. I'm assuming that would be a much larger surface area than a typical knife bevel, but similar force? Using a guided system, I try not to put much force at all into any of my stones. The second statement reads as though there might still be a material removal advantage with fine electroplated diamonds if using light pressure as one does on a guided sharpening system, but maybe that "critical pressure" threshold isn't hugely different from a "normal/regular" stroke on a system such as a TSPROF.

 

[DeadboxHero]

It certainly can make a difference, however heat treatment is a significant factor also.

Don't forget, geometry, sharpening technique, abrasives etc. in no particular order.

Not to mention most importantly how "sharpness" is being tested/evaluated.

 

[Gottagofishn]

I use a BESS tester to check results on all knives. In regards to how sharp different steels can become… in my experience the finer or more dense the particles (CPM vs stainless) the sharper edge can be developed. There may be other factors like hardness that can also affect the apex so that’s a pretty general statement.
Some knives I can get to 40, some only to 130. I believe it is a limitation of the steel makeup.
And… controlled angle sharpening will give a more consistent edge… for me.

 

[DeadboxHero]

I use a BESS tester to check results on all knives. In regards to how sharp different steels can become… in my experience the finer or more dense the particles (CPM vs stainless) the sharper edge can be developed. There may be other factors like hardness that can also affect the apex so that’s a pretty general statement.
Some knives I can get to 40, some only to 130. I believe it is a limitation of the steel makeup.
And… controlled angle sharpening will give a more consistent edge… for me.

The rabbit hole goes much, much deeper than carbide sizes, retained austenite is one of many hidden factors that doesn't get much attention yet is quite significant in the end user experience whether they are aware of it or not.

 

[Mr.Wizard]

Initially I don't see how those two statements change much about what I'm curious about, but I don't know anything about honing a straight razor.

If your use is also low pressure either due to very light force or a very large contact area (e.g. flattening/thinning the face) it should apply quite well. When "roughing in bevels" I am not light about it.

 

[MolokaiRider]

I have nothing here to offer other than I can get 1075 sharper than anything else I've got, and that is likely due to my sharpening tools and (lack of) skill set.

It does have a pretty fine microstructure that helps, as well as ease of grinding.

 

[TheOne45]

I would say there are two different things when trying to make the knife sharp.
First thing is 'easy to grind' and the second thing is 'easy to sharpen' or with other words-how easy to make the knife sharp.
A while ago I was sharpening pocket knife similar to Buck 110. The blade was easy to grind - to remove the metal and to establish the apex but very tricky to make it sharp-to remove the burr and get a clean edge.
Cliff Stamp also mentioned this in one of his videos.