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

Posted by jasonstone20 
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Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 17, 2017 08:36PM
I had a dicussion online a year or two ago when I was trying out a #325 DMT edge, and suggested it. The other person responded, saying they prefered a 6k-8k high polished edge, because it easily floated through what they were cutting. I was reminded of this while reading an old thread doing some research in grit finishes and stropping:
[www.cliffstamp.com]

Here it is described that high polish edges work well on slicing and push cutting work, and need less initial force to start the cut:

Quote
Cliff Stamp
The cutting ability in general tends to be higher even on slicing work. On the 1/2 hemp for example, while both apexes will make a cut with 4-5 lbs, the one with the very high polish has practically no horizontal component. In extreme contrast, you can readily feel the force required to pull the 120 Sigma Power through the cord. This is one of the nagging reasons I don't really like the way I currently measure slicing sharpness or cutting ability as it ignores that component of the force. However in general it is always going to be less than the vertical component so it is a small correction generally, especially for worn edges.

The reason most people think this isn't true and polished edges don't cut well on slicing is that all the polished edges they have seen have no slicing aggression, you can slide your finger along them without harm. Note the guy selling traditional slip joints who even opened the blade by pressing his thumb against the apex and when I commented on it in his YT video he noted the knife in question was among the sharpest of modern manufactured blades. The entire perception of performance has been warped by the over use of buffing.

Which further got me to think about if you optimized cutting ability and grit finish you could get a knife that easily cut through materials lessening hand fatigue, and improving control and safety.

"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
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sal
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 17, 2017 10:27PM
Hi Jason,

When we were developing our sharpener and doing cutting tests ( 1977/78 ) we learned that a highly polished edge would stay sharper longer than a coarse edge, but a coarse edge would cut more aggressively. The combination was a highly polished thin serrated edge.

This is easily demonstrated with our utility kitchen knives (K04). If you'll email your mailing address to me, I'll send you one to play with.
sglesser@spyderco.com

sal
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 17, 2017 11:59PM
Sal,
Email sent, thank you.

"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
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When speaking about steels like x50crmov around 55 HRc my experience is finishing on abrasives around 40 microns gives me the sweet spot between initial sharpness and edge retention - which means 3 to 4 weeks every day kitchen use before some steeling/honing is needed for keeping the working sharpens of an already established edge and after 8 to 12 weeks another sharpening is necessary to remove the fatigue metal from plastic deformation (both in use and from steeling).

btw. the only serrated knife i have experience with is a Victorinox 4.5 inch paring knife and i Keep it kitchen sharp enough with only steeling it every month a half a dozen passes on a fine cut steel - serrated knives have their place in our inventory (I was sceptic, now I am believer )

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Life is GOOD!

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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 26, 2017 04:25PM
Sal,
I just got he knife yesterday. I plan on using it as my main kitchen knife for a while. I plan on doing a write-up and maybe a YouTube video. Thank you again.

"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 26, 2017 07:45PM
I just made breakfast with the knife. I am very impressed. I made cheese home fries, and the knife was excellent chopping and slicing. It cut potatoes just as easy as onions and peppers, as well as a stack of American Cheese, which can be difficult to slice because it is sticky, but the Spyder-Edge K04 went right through it.

"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
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sal
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 27, 2017 12:41AM
Thanx Jason,

I'l post more thoughts tomorrow. It's a long post and I'm not that great at typing. You have a "stock" edge. I have a mod that I believe improves that. The knife doesn't look like much but it does cut.

sal
sal
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 28, 2017 09:18PM
Hi Jason,

There are some points I’d like to make. The knife, as stock, is ground very thin. It cuts very well but it is a very thin edge. What I like to do is sharpen it on a Triangle Sharpmaker, using 3 strokes on the left and one on the right at 30 degrees. This gives you kind of a micro-bevel that is very effective. I can try to do one of those here and send it to you or you can try it for yourself. I use a loop and I continue on the corner of the white stone until all the burr has broken off. It takes about a 10 or 12 power loop looking at it every 15 or 20 strokes to be able to see that. That, I found, works the best for all of our serrations. We use a very thinly ground bevel, but it’s really too thin, for almost any steel, to maintain for very long. Most people will just use it and eventually sharpen it. Some people just use it and buy a new one when it’s dull which really takes a long time. In the places we test them, usually sub shops where they cut all day long, we trade them out after a year or so. We then study them in the lab under some magnification. But as I have mentioned before, I found that a serrated edge cuts aggressively like a ‘toothy’ edge but breaks down faster because bigger pieces break off. But then when it is highly polished, that is when I think you get the best cutting performance and the best edge longevity.

sal
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 28, 2017 09:45PM
Sal,
Very interesting, thank you. The knife is definitely designed well for the kitchen, and it has easily tackled everything I have used it for. I can see it lasting a long time for home cooking use.

"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 30, 2017 01:25AM
Sal,
I do have a Spyderco Medium and UF Triangle rod, as well as a Medium 701 Profile sharpener, and a Lansky CrockStick Diamond Turnbox, as well as a Lansky Medium pocket CrockStick model, and a small UF keychain model. I have been wanting to buy a Spyderco Sharpmaker for sometime.

"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 30, 2017 02:35AM
The Sharpmaker is very good at sharpening serrations, I can attest to that. I also like Spyderco’s serration pattern for both how it cuts and how easy they are to be sharpened compared to some of the other serration patterns out there. I am thinking about getting one of the serrated K04’s, as my wife is fond of serrations and I only have garbage serrated kitchen knives. My dad is using some of the Spyderco serrated paring knives as steak knives after he complained to me about his old steak knives. I had a few sent to him and he has been quite pleased with them. I’ll probably be sharpening those soon, though he hasn’t complained at all about them getting dull. I just like to sharpen my parent’s knives every few months for them.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 30, 2017 05:04AM
gunmike1,
The Spyderco K04 Sal sent me is like a cheap stainless serrated knife, except way better. It has a great serration pattern and is made out of a awesome 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
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sal
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 30, 2017 05:34PM
Jason,

204MF on the way.

sal
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
December 01, 2017 02:21AM
Sal,
Thank you very much. That was very generous and kind of you.

"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
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Edited 1 time(s). Last edit at 12/01/2017 02:28AM by jasonstone20.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
December 05, 2017 08:32PM
Sal,
I got the sharpener. Very nice product! I like it more than the Lansky Crocksticks that I have. Thank you again. I had dulled the tip of the K04 cutting a sandwich that was on a ceramic plate, and I was able to get the knife tip sharp again, along with getting the whole knife to cut a free hanging head hair in half. The advice with the three passes on the left and one on the right worked perfect. The knife floated through food before, after sharpening it is effortless.

"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
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Edited 1 time(s). Last edit at 12/05/2017 08:36PM by jasonstone20.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
January 19, 2018 07:17PM
Quote:
[www.spyderco.com]

Quote
Cliff Stamp
Mike Swaim did a lot of work on this in the 90's on rec.knives and besides the obvious he also showed a few interesting things which are not so trivial. One of them was when a knife cuts really well it has edge retention far more than you might expect. Just think about edge retention = what is it really? It is the steel resisting deformation, wear, and chipping . Now obviously these are influenced by the steel but just ask yourself the obvious question :

- which bends more, a very strong piece of steel which is bent with a 100 lbs force or a really weak steel which is bent with only a 1 lbs force

The really weak steel could actually bend less because a much lower force is applied to it. What Mike noticed was that the blades which cut better had better edge retention and that he could increase the edge retention simply by making the knife cut better. Of course what is happening here is that the knife is seeing less forces on it in use because it is cutting better. With a better cutting knife, with a more ergonomic handle, the user has less fatigue, has more control and the knife is much more stable in cuts.

This is why, among other things, you don't see a lot of people complaining about ABS knives even though they use the most basic of steels. However they take cutting ability, comfort, ergonomics, etc. to very high levels. Of course when you do all of this -and- you use a very high end steel, and you do a very high end hardening, well the knife just keeps getting better and better.

"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
February 28, 2018 05:23PM
In reprofiling the Benchmade 555 Mini-Griptillian, I noticed a great improvement in cutting ability. The knife came from the factory very sharp, and I was only able to get it a little sharper, but when I reprofiled the knife from 20* per side to 10* per side, it cut so much better. This got me wondering, is there any reason not to go down to lower angles (closer to a zero grind)? The only reason I can think of is durability, but with my EDC use I haven't had any durability issues ever. Has anyone found for their EDC that durability was more of a priority than performance?

"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
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Jason, I would go as low as possible but still just thick enough to hold up to the hardest use it will see... You will have to play around with it to dial it in.
I think you need look no further than what happened with the Spyderco Nilakka to see why zero grinds, or near zero grinds, are a problem for modern companies using the more popular higher carbide steels. Add to that what seems to be a mostly accepted reality of overheating (even slight) of edges, and a zero grind wouldn't be able to be fabricated with current standards of manufacturing for many companies. Now, we all wish for the very best in fit and finish and production methods, but eventually companies have to hit their target price and some things have to go - besides, it's not as if they're producing bad knives, maybe just a little below optimal for us. You see a strange reflection of this reality in older (much older, non-relocated companies) like Herder, Opinel and many other European kitchen knife brands (and a lot of this over in Japan too) where keeping to the old methods erases some of the new problems, and the knives they produce are still some of the finest cutting tools available, even if the hardness is in the mid-50's.
The final factor for higher angles and subsequently thicker edges is the well known argument of "making the knives endure less skillful customers", which is a very real concern and not at all something to dismiss offhand. (not that I think anyone was doing so)
KWB
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
March 01, 2018 02:00AM
I made some kitchen knives for our use in the kitchen when I first started making knives, it was .125 stock 1.25 in wide grind, .010 at the edge and the cook chipped the hell out of it. I soon realized not everyone treats fine tools as such. Now that same knife is .020 and serrated no more problems. I will note ht is on par came out of the same batch from the first knife Cliff has from me.

Contact 570-486-9095
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
March 01, 2018 03:38AM
razoredgeknives,
Exactly, is there a reason not to do this to your EDC or kitchen knives?

Luisknivacc,
I think that there is a ceiling for this type of optimization, although I have used in on up to S30V, I think 154CM/VG-10/440C might be a more comfortable limit.

Kyle,
I have been taking small breaks, which is why I didn't get worn out on knives in a year or so. But that is awesome advice.

"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
July 17, 2018 01:58AM
Video:
[youtu.be]

I have had mirror polishes last longer for they way I cut also, which is mostly 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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 25, 2018 05:13PM
Tire cutting: Neroknives on YouTube:

Medford Marauder vs Spyderco PM2:
[youtu.be]

"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
November 28, 2018 06:26PM
Some interesting stuff in that channel. Thank you Jason...I've discovered quit a bit of interesting youtube content through you.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
May 22, 2019 07:04AM
I have been thinking about this topic for some time, the relation between cutting ability and sharpness, along with edge angle and behind the edge thickness;
[www.bladeforums.com]
Quote
Baron Mind
So we know two things that increase cutting performance are lower edge angles and lower BTE measurements.

These properties are inversely related however. One must assume that the benefit from lowering the edge angle outweighs the resulting thickening of the BTE measurement, but has this been proven to be true, and if so, is there a point where that is no longer true? I.e going from 40 inclusive and 20 thousandths bte to 30 inclusive and 25 thousandths BTE results in greater cutting performance, but going from 30/25 to 20/30 isn't?

Just a random pondering of an edge junkie. Any idea? Theoretical, mathematical, or empirical contributions are all welcome.

Quote
tomhosang
Fair enough. I just posted the video for anyone who wanted to watch. Here's the summarization:

He tested 2 Manly Wasps in 12c27. One being 0.016" BTE and the other being 0.008" BTE. So, the exact same knife, in the exact same steel, from the exact same maker. The only difference being the BTE thickness. His test media is cardboard, which is something many of us encounter on a daily basis (way more than rope). This is why I said it depends on what you're cutting. The cardboard does not bind up on the knife like something like rubber would do. For this reason, BTE doesn't matter as much. Steve got very similar results between the two Wasps. The 0.006" cutting 14 feet more than the 0.016" one. This may seem like a lot, but is only an 8% difference. Almost negligible. It is not a black and white subject. Any difference in BTE thickness is negated by the edge angle, the edge finish, and the media being cut. It will or won't make a difference based on those factors.

Also, Ankerson's tests are a tremendous resource. It gives us a great baseline to go off of. The same thing goes for any of the YouTube testers including Steve or myself. All of this is to give people a reference point for certain steels. Depending on the knife, company, use, etc; anyone's experiences may vary.

Sharpness vs Cutting Ability
[knifesteelnerds.com]

"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
August 20, 2019 03:14PM
My sharpest production knife is a KaBar BM13, full height holllow grind, and in 440A steel. This is the embodiment of what I would like in a production knife as far as knife steel and grind. It is 0.0125" behind the edge and at 8* Degrees Per Side. This is the optimal edge bevel geometry for me, as it is durable enough to my EDC uses. It rivals my two favorite custom blades I EDC, one from Kyle Bettleyon and one from Shawn Houston/BBB/Triple B Handmade knives. It goes to show that performance geometry can be done in a production knife. Just look at Douk-Douks, Opinels, SAK, and the Herder Paring knife. It is possible, we just need to ask for it from our production companies.

"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
October 30, 2019 02:56AM
[www.youtube.com]




"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
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Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
December 26, 2019 08:31PM
I am wondering something. Take this:

Quote
Cliff Stamp
[www.cliffstamp.com]

"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. The greater the size and volume of carbide, the greater the angle required to keep the edge stable."


If lets say a Type I steel was at 8° DPS, and a type II steel was at 20° DPS, would the Type I at 8° DPS be sharper, have more cutting ability and edge retention than the Type II steel at 20° DPS? The CATRA TCC on the chart of the VSharpAngle3 program shows this:

Type I:
1095 @ 60 HRC, 8° DPS = 664 TCC

Type II:
440C @ 60 HRC, 20° DPS = 569 TCC

And if we compare a Type III steel at 30° DPS @ 60HRC =
20CV = 578 TCC

"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
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Edited 1 time(s). Last edit at 12/26/2019 08:35PM by jasonstone20.
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
May 16, 2020 04:48PM
[www.youtube.com]




"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
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cKc
Re: Cutting Ease:Cutting Ability, Grit Finish, Edge Angle, & Thickness Behind the Edge
May 16, 2020 05:04PM
haha. its funny when i see myself in a post.

Quote

Type I:
1095 @ 60 HRC, 8° DPS = 664 TCC

Type II:
440C @ 60 HRC, 20° DPS = 569 TCC

And if we compare a Type III steel at 30° DPS @ 60HRC =
20CV = 578 TCC

Jason are these actual, or predicted?

this specific type of testing is what i dont like about cartra tests that make all steels the same edge thickness and angles as equalizers..
the entire point of HT and steel selections is not not equalize, but to amplify.
so the only sensible Cartra testing to tell me which knife has best edge holding is to take edge steel to the lowest possible grind and apex that will not fail under a specified test load, and then do the cartra test of each and see what the rankings are.

if you are going to equalize, you might as well just get the cheapest.

same thing goes.. that if 1 steel has a 50% better edge, but takes 2 times longer to restore the edge, then in my rankings, this steel loses in my optimal ranking

.

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It's not Cliff, its Dr Stamp
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