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How To Maximize High Sharpness Edge Retention

Posted by jasonstone20 
How To Maximize High Sharpness Edge Retention
May 16, 2019 08:43AM
After playing around with burr sharpening and stropping for the last year, I have found three things:
  1. Initial Sharpness can be equal to No-Burr Sharpening
  2. Slicing Aggression is there, it passes tests, but No-Burr Sharpening excels in slicing, even at high finishes
  3. High Sharpness Edge Retention is minimal, as the edge degrades even when not in use, slicing aggression is the first to go


I have tried the one of the better 1.0 u Diamond Sprays (Portland Knife House) which is excellent, as it both polishes and leave bite on the edge, and Maggards CrOx 0.5 u, and it does a similar thing to the PKH diamond. I don't think the actual issue is stropping, I think that edge health is the problem.

*edited for spelling and grammar

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser



Edited 1 time(s). Last edit at 05/16/2019 08:43AM by jasonstone20.
me2
Re: How To Maximize High Sharpness Edge Retention
May 26, 2019 07:10PM
What do you define as high sharpness and as minimal? I find high sharpness can persist quite a while, but my standards may just be low. For instance I was shooting my pistol yesterday and kept missing the bullseye. The solution? Get a target with a bigger bullseye.
Re: How To Maximize High Sharpness Edge Retention
May 26, 2019 08:55PM
me2,
I was thinking the same thing about adjusting my standards also. I define high sharpness as starting at being able to pass a HHT 0 with beard hair and ending at passing a HHT 3-4 with head hair. I have been using the upper end of this scale for some while (HHT 3-4 with head hair) and I really don't see the benefit over that lower end of the scale. If it was a straight razor I was sharpening it would make sense, but it isn't so it doesn't.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
me2
Re: How To Maximize High Sharpness Edge Retention
May 27, 2019 08:31AM
Oh yea. I'm not using such high standards. There is a fundamental issue with high sharpness edge retention. As you raise the standard, there is an exponential drop in longevity.
Re: How To Maximize High Sharpness Edge Retention
May 28, 2019 07:29AM
me2,
My EDC use is fairly light, just opening mail and food packages, along with breaking down cardboard for the recycling. I high sharpness edge (HHT3-4, head hair) in a weeks worth of use ends up being a HHT 0 (head hair). At the end of a month, my main EDC blade will still shave.

edit:
What I had been playing around with for the last year was getting a mirror edge, that will still have slicing aggression and decent high sharpness edge retention. What I have found is that I could reliably get an edge that would pass an HHT 3-4 on beard hair off the stones, but to get it up to a HHT 3-4 on head hair, I would have to strop (regular production knives, on customs with a nice HT and steel that has high edge stability, I can get a HHT 3-4 on head hair off the stones). Stropping seemed to reduced the 'health' of the metal on the edge, and if you over strop you end up with a hard to remove micro-burr. On another topic, it isn't that a high polished edge can't have slicing aggression, it is about the health of the edge and not overworking the steel, which ends up fatiguing it in my observation. The steels I have been playing around with are 8Cr13MoV (Spyderco) and 154CM (Benchmade). I have noticed it is the difference in the two steels taking a high polished, steeper angle (closer to zero), with the 8Cr being easier and 154CM harder and more subject to steel fatigue, along with micro-chipping in use when a burr is formed, while with the burr-free sharping I don't have that issue.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser



Edited 1 time(s). Last edit at 05/28/2019 07:51AM by jasonstone20.
me2
Re: How To Maximize High Sharpness Edge Retention
June 03, 2019 07:32AM
That's what you'd expect, but it's nice to see the expectations conformed. I'm using BD1 from Cold Steel and 8Cr13MoV from Byrd now. The BD1 seems ok, and I've always liked 8Cr13MoV. I don't take them that high in sharpness though. Medium Sharpmaker rods or maybe fine is about it.
sal
Re: How To Maximize High Sharpness Edge Retention
June 03, 2019 08:15AM
Me2's comment about a larger bulls eye is very profound in many areas of life. I also think that the standard may change depending on the function. We found that serrations will protect the cutting edge and we began using multiple level serrations about a decade or so ago and found the longer tooth protected the shorter teeth which protected the recessed cutting edge. Kinda like contingency plans. Doesn't work much for hair though. Hard to shave with serrations.

sal
Re: How To Maximize High Sharpness Edge Retention
June 03, 2019 06:39PM
The problem I am working on now is what edge angle and finish works best for my EDC uses. I had been running high polishes because I mostly push cut. I am going to try a Soft Ark finish next, then a Spyderco Med. rod finish. The two knives I am using are a Benchmade Mini-Grip in 154CM, and a Spyderco Resilience in 8Cr13MoV. The 154CM is sensitive to lower inclusive angles (closer to a zero grind) and high polishes, it will start to micro-chip at about 10* DPS/20* inclusive. The 8Cr13MoV is pretty much happy with what ever I set it at, although burr removal can be difficult, so I have been using burr-free sharpening. I don't really think that achieving a high sharpness/high polish is necessary for my EDC use, I am not seeing an improvement in performance in use or edge retention. I only see it passing sharpness tests that you need a high sharpness edge for. I am getting mixed results with stropping, so I have decided to leave stropping out of this, and I am also trying to not lose slicing aggression, and stropping seems to degrade it. Getting a tree-topping (arm hair) edge seems to be just fine, and I can achieve that edge readily straight off the stones, and a coarse edges ( DMT 325, Norton Fine India).

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
Re: How To Maximize High Sharpness Edge Retention
June 05, 2019 11:04AM
I think I found the cause of the issue I was having with the strops and stropping. I decided to clean and reapply compounds, and my strops were awfully loaded. So I cleaned them, and I had good results from the Flexcut strop and Flexcut Gold compound on the Benchmade Mini-Grip in 154CM

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
sal
Re: How To Maximize High Sharpness Edge Retention
June 06, 2019 04:56AM
Hi Jason,

Looking forward to seeing where you put your "Bulls-eye" for EDC. My old VTR100 would do 165 mph, though I never went there. Daily speeds speeds were usually under 100 MPH, occasionally to 135. Daily "bulls-eyes are an interesting range.

sal
Re: How To Maximize High Sharpness Edge Retention
June 09, 2019 09:38PM
sal,
What is your opinion on stropping?

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser
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