Welcome! Log In Create A New Profile

Advanced

Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge

Posted by jasonstone20 
This forum is currently read only. You can not log in or make any changes. This is a temporary situation.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
May 16, 2020 05:29PM
cKc,
Predicted, using Larrins TCC formula.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
May 16, 2020 05:31PM
cKc,
The other issue with CATRA is that is doesn't take into account lateral loads, or for push cutting.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 14, 2020 02:35PM
How low of an angle can you go on steels? Is Roman Landes findings on edge stability and classes of steel a hard and fast rule, or just a guide?:
Quote
http://www.cliffstamp.com/knives/articles/edge_stability_review.html
Dr. R. Landes explored this subject in detail among other issues on cutlery steels in "Messerklingen und Stahl"4. Landes is a knifemaker and metallurgist who specialized in cutlery steels. He did extensive and quantitative work in what he defined as edge stability which was identical to Johnston's defination of edge integrity. Landes measured the deformation of edges at the same edge cross section in response to microloading. He classifed steels into three groups, type I, type II, and type III mainly based on carbide volume, 0.5-5%, 5-15%, and greater than 15% respectively. These groups needed different angles to both take and hold a high polished sharpness, 8-12, 12-20, and 20-30 degrees per side respectively.

Can you take AEB-L to below 10°DPS? M390 to below 10°DPS? Will a microbevel stabilize a steel like M390 if it is a 10°?

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
cKc
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 14, 2020 05:05PM
Quote
jasonstone20
How low of an angle can you go on steels? Is Roman Landes findings on edge stability and classes of steel a hard and fast rule, or just a guide?:
Quote
http://www.cliffstamp.com/knives/articles/edge_stability_review.html
Dr. R. Landes explored this subject in detail among other issues on cutlery steels in "Messerklingen und Stahl"4. Landes is a knifemaker and metallurgist who specialized in cutlery steels. He did extensive and quantitative work in what he defined as edge stability which was identical to Johnston's defination of edge integrity. Landes measured the deformation of edges at the same edge cross section in response to microloading. He classifed steels into three groups, type I, type II, and type III mainly based on carbide volume, 0.5-5%, 5-15%, and greater than 15% respectively. These groups needed different angles to both take and hold a high polished sharpness, 8-12, 12-20, and 20-30 degrees per side respectively.

Can you take AEB-L to below 10°DPS? M390 to below 10°DPS? Will a microbevel stabilize a steel like M390 if it is a 10°?

you just answered the first in the above quote, Class 1 steel.

Quote
above
These groups needed different angles to both take and hold a high polished sharpness, 8-12

I think with m390 or anything like that. you can take it to any angle. the question is.. how stable is it, and then based on the hardness, HT, and what you want to cut with it.

Quote
Jason
Will a microbevel stabilize a steel like M390 if it is a 10°?

What do you mean? do you mean if you have a 10degree bevel and put a 15 degree micro bevel will it stabilize it? Edge stability is only talking about the apex angle, so if you have a 15dps apex, the 10dps doesn't really come into play for apex stability, only for structural stability of the entire knife.

for example, you can put a 20dps bevel with 0.0005" cross section on a knife that this 7dps following this.. but when you apply a compressive load to the knife.. meaning you want to cut something which 20dps puts enough stress on for the force to push back into the steel, then you will ripple the blade, or worse chip and tear out steel behind the apex on a harder brittle steel.

the edge angle in question to the steel I think is entirely dependant on the force applied to the cutting and the material.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 14, 2020 05:16PM
Quote
cKc
if you have a 10degree bevel and put a 15 degree micro bevel will it stabilize it?

Yes.

I am just wondering what will happen when you do this:

Quote
Cliff Stamp
[www.cliffstamp.com]
I have gone under that significantly, D2 as low as ~5 dps with very high sharpness, very resistant to cutting deformation (it doesn't deform on carboard/ ropes, cutting on hard woods, etc.).

[www.cliffstamp.com]
In general 15 dps is a very large angle, it is often used for chopping blades. I don't normally even run that high, closer to 10-12 dps unless I am cutting very harsh woods.


[www.cliffstamp.com]
It has to be a technique thing, Alvin Johnston used to run 6-8 dps apexes on everything, including those steels. He would deep hollow grind full flat knives as they didn't cut well enough, sharpen flat to the stone, so the edge was 2-3 dps, and the micro-bevel at 6-8 dps. His own knives were full hard 1095/M2, but he would regrind anything, including Buck's etc. and he always sharpened them the same way.


Because I have gotten a few different results from D2, VG10, S30V. I have had edges just suddenly lose sharpness, have micro-chipping, roll, or do nothing when taken below 10-15°DPS. Even on the same knife I have had conflicting results. I can't really make heads or tails of what is happening, other than maybe it has to do with the sharpening technique being used, or I am running into bands of carbides in the steel.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
cKc
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 14, 2020 05:49PM
Quote
Jason
Because I have gotten a few different results from D2, VG10, S30V. I have had edges just suddenly lose sharpness, have micro-chipping, roll, or do nothing when taken below 10-15°DPS. Even on the same knife I have had conflicting results. I can't really make heads or tails of what is happening, other than maybe it has to do with the sharpening technique being used, or I am running into bands of carbides in the steel.

could be so many things, including how its being sharpened, the HT, and the edge condition, and the pressure on the stone..

if you take something with 25micron clusters.. and make it 7dps, then its 100microns of apex to hit 25microns that's 0.004" lengths for 0.001" cross section..

so you could well be getting stability damage in the first 1-3 thousands of edge. for no reason

at 15dps its a little less than 1/2 that length to get to the same cross section a lot more support..

but determining if your edge is going to get ripped apart is going to factor into how weak it is from sharpening, and what you are cutting.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 14, 2020 07:34PM
Quote
jasonstone20


Because I have gotten a few different results from D2, VG10, S30V.

Just to clarify, edge stability is a measure of the apex to retain a high push cutting sharpness. It isn't a measure of how the edge resists rolling, chipping, etc. .

The difference in steel from one knife to another is likely far more than among steels. To clarify, I am saying that if you look at all the D2 knives out there, the difference in behavior would be similar to the difference that you see if you looked at random steels.

The composition of all D2 blades won't be the same, the way they are hardened won't be the same, when you sharpen the knife, the random section of carbides, martensite and austenite you get won't be the same from one sharpening to the next.

Then, on top of all of that, when you use it, there are huge variations even in the same type of cutting.

Now, how do you draw conclusions from that, when there is so much noise - in one word, CAREFULLY.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 14, 2020 08:22PM
Cliff,
That is one reason I am hesitant to give strong opinions, and talk more in generalities. I can sharpen the same knife ten times in a row, get the exact same results with initial sharpness and edge retention, and then sharpen the same knife ten more times and get variances in initial sharpness and edge retention. That doesn't really build confidence that you know what you are looking at.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 12:00AM
Cliff,
Quote
Cliff Stamp
Just to clarify, edge stability is a measure of the apex to retain a high push cutting sharpness. It isn't a measure of how the edge resists rolling, chipping, etc. .

Thank you, I was wondering about that.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 12:08AM
Consider :

[A2]



and worse [D2]



(Larrin)

Now imagine drawing a line across that, that line is the apex of your edge, consider the apex formed by :



The apex which would be the green line has big massive carbides, likely to get torn out in sharping, and if not likely torn out quickly in use. But the apex formed by the red line is mainly through well tempered martensite.

Sharpening this steel multiple times could easily get different results because of the just general inhomogeneous nature of the steel. It is likely why the guys that really like/use D2 like Dozier tend to favor coarse finishes because the grit will mask that inhomogeneity.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 12:13AM
Cliff,
Quote
Cliff Stamp,
It is likely why the guys that really like/use D2 like Dozier tend to favor coarse finishes because the grit will mask that inhomogeneity.

Yeah, that is the other thing. I am using super fine grits, above 3u and usually 6k JIS if not higher.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 12:35AM
Very high grits on high carbide steels likely would be prone to that, more so on traditional ingot steels and ultra-high carbide PM steels which will still be prone to aggregation.

I would be curious what kind of results you would get with steels which are far more homogenous like O1, AEB-L, W1, etc. .
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 12:38AM
Quote
CliffStamp

I would be curious what kind of results you would get with steels which are far more homogenous like O1, AEB-L, W1, etc. .

I get great results, quite easily, and consistently, with those types of steels. I favor them because of the consistence.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 01:21AM
That makes me think you are just seeing real data, and unfortunately what you are comparing it isn't.

High carbide steels are inhomogeneous, work is inherently variable - if you are getting consistent results in that kind of situation, well you are just making up data. Unfortunately a lot of people are. You can see the people who have real data, and they are always surprised because it contrasts so strongly with what is being promoted :

[www.youtube.com]

Alex tries as much as he can to reduce errors, but even then he can't tell apart S30V and 8Cr13MoV. This is a "Super" steel vs a "Budget China" steel, and he still can't show one does better than another in edge retention cutting rope, cardboard, etc. .

He does a really great commentary/discussion on many of the problems, especially how do you decide when to stop, and how hard it is to put a precise number on this "end" of the test.

That is the reality of actual use, that is what actual data collection looks like, you are plagued with errors, nonlinear effects, inconsistent results, etc. . That is kind of why people go to school to learn how to handle these as the solutions to them are nontrivial.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 03:37PM
Cliff,
Why in the world are these steels being used for knives then if the exhibit that type of behavior? I would think that behavior is the last thing you would want in a knife.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 04:07PM
Quote
jasonstone20
Cliff,
Why in the world are these steels being used for knives then if the exhibit that type of behavior?

That's the reality of tooling in general. It is why when you look at performance from that perspective you can't look at ONE use but you would look at something like :

-what is the average damage over 1000 use cycles
-how long does the blade need to be sharpened on average over 1000 use cycles
-how many times is the part replaced due to gross failure in a 1000 use cycles

and so on.

It is why I often take so long before I will talk about a knife or stone, etc. . It takes a long time for me to get comfortable because I want to see if performance patterns repeat, etc.. Anything can happen at random in one run, you need to look at a large amount of runs to make a conclusion.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 04:22PM
Cliff,
That makes me wonder what the numbers look like for unwanted behavior with steels used for knives.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
cKc
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 04:25PM
Quote
jasonstone20
Cliff,
Why in the world are these steels being used for knives then if the exhibit that type of behavior? I would think that behavior is the last thing you would want in a knife.

Its a good question. maybe if you think you have something amazing, but you don't realize you don't, then you want it.

Emperors new clothes.

think about how people that relied on flint napping or obsidian would look at any knife in any steel no matter what compared to those 2 options.

if you never use something in a way that puts any steel to a limit of stress, then any steel will work, and you can convince yourself what you have is duper

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 04:45PM
Quote
jasonstone20

That makes me wonder what the numbers look like for unwanted behavior with steels used for knives.

I am not sure what you mean here, what numbers?
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 05:04PM
Cliff,
Say for sharpening 154CM, what percentage are you going to get a good edge, vs micro-chipping/carbide tearout, rolling, edge collapsing.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
June 15, 2020 07:29PM
Quote
jasonstone20

Say for sharpening 154CM, what percentage are you going to get a good edge, vs micro-chipping/carbide tearout, rolling, edge collapsing.

Now that is an interesting question indeed. I could make generalizations, like D2 would be worse than A2 which would be worse than 1095. But as to numbers, I would not even be able to guess intelligently. It would make for an interesting experiment.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
September 29, 2020 10:13PM
So Sal included two Spyderco Counter Puppy knives with the Spyderco CBN Benchstone he sent me. One is has a serrated edge, and the other a plain edge. I touched up the plain edge after I had used it for a few days with the 6x3 Dan's Surgical Black Arkansas stone. Making lunch, I noticed that the serrated knife cut a lot better, while the plain edge would bind. This is going to be a good way to be able to compare a serrated edge vs a plain edge, since both knives are the same model. I need to take some measurements of the behind the edge thickness and edge angle for both blades. The serrated edge also felt sharper out of the box.
More to come.....


"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
October 01, 2020 12:32AM
Update: I sharpened the plain edge Spyderco Counter Puppy with the Tormek T-4, to a sharpness that will push cut receipt paper 1/2" from the point of hold, cross grain. The plain edge knife now performs as well as the serrated edge in the cutting I was doing.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 08, 2020 12:50AM
It is amazing to see what happens when a blade has been reground, and has an appropriate edge finish for the work being done. To be able to cut with ease is a great feeling. I was cutting blackberry shoots from the sidewalk, as the city had cleaned up the area, and I like to cut anything sticking out into the sidewalk as I walk by. I was using my reground SAK Super Tinker, with the #400 Spyderco CBN grit finish. Using snap cuts, everything was cut on contact, and on the first try.

"I am still discussing issues of steels and performance at this stage." -- Cliff Stamp, May his memory be a blessing
"Life is GOOD", -- Stefan_Wolf, May His Memory Be A Blessing
WordPress YouTube Facebook Patreon Locals Instagram Twitter