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Sharpening Gain Vs Sharpening Time (again)

Posted by cKc 
cKc
Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 06:35AM
much discussed in many posts. seperate here because it relates to a specific video I just watched.


only 1 run done, so he realizes that its not that reliable, but if you do take it at face value that the numbers are inidicitive and look at some of the comments. i just replied to one.




summary
knife 1 600grit 5min sharpening time, cut 60ft material to stop point
knife 2, 8000grit, 35min sharpening time. cut 98ft to stop point

Quote
Guy
So you get 160% improvement for 30 minutes of labor - for me, this is definitely worthwhile. I use my knifes bushcrafting/hiking so re-sharpening isn’t always as easily available. I also tend to favor harder steel that naturally keeps its edge longer by nature, it good to know that putting in that extra time upfront matters.

it really shows that people to me, don't think about work cost, or work effort. 160% gain.. worth the time. but... its not that much gain.

Quote
my reply
Depends how you look at the math, and how you like to use knives to determine if there is a benefit. if you are bushcrafting you prob want a finer edge for woodwork anyway, but...
160% sounds great if you don't actually look at the numbers.
5min to do 600grit for 60ft, and 35min to do 8k for 98ft.
that's 12ft of work per minute of sharpening for 600grit, vs 2.8ft of work per min of sharpening of 8k. now if you were paying an employee to work, which would you think is the most beneficial? if you had an employee whose job involved 8hrs of knife work a day of this nature, do you want 12ft per min or 2.8ft per min?
apart from anything, it's unlikely during a day or an outing that each resharpening is going to required 5min on 600grit. typically it would be 30seconds to restore the edge at that level in the field on a pocket stone or small steel hone.. these are soft steels easy to restore.
if you are out for a multi day trip, then that 8k prob wont survive a weekend of work if it can only handle 98ft cutting. so you are going to need to resharpen anyway. in the middle of the dark in the forest, do you want 35min or 5 min to get an edge back.


This really exemplifies what I think the modern trend we are seeing is. people are looking at 1 side of the gain, without looking at the total cost of that gain.

All these people promoting certain steels. why are they not asking, that over the last 80 years these steels have been available why all the factories that rely on high performance cuts of meat and food, and getting maximum quality, per minute have not taken on all these steels that are claimed to have better edge longevity.

we are talking about multi million dollar industry..

a butchers knife in vicnox is $20-$30, forget custom makers.. forget small-time operators like Benchmade and spyderco. if vicnox wanted to produce s110v, m390, k390 or any of these for butchers knives, and built the machines and tooling to do it, then we would be talking about $60 knives, not $400 knives producing a few thousand a day of them if they wanted to.

for one meat plant operator, or tuna fish processor, over the course of one shift can be processing $50,000 of meat.. weigh that up in lost income sharpening knives.. everything about the industry when you look at it, is about increasing productivity, longevity, and profitability..
if it was a thing. it would have been done long ago.

it would be great if anyone could find research on this. i am pretty sure that the big companies definitely do research on this stuff.
i don't mean the companies selling all sorts of wild steel choices to the minority of the world that collects knives and hobby nerds out over stuff like us. i mean the industry supplying knives to the commercial knife using sector.


some things to consider about the arguments you might hear could be things like.

"Sure, this super knife at 65rc, and 0.001" behind the edge is a million times better than the junk knives found in kitchens, but it requires a special delicate user who knows what they are doing to use it"

ok, so lets consider this.. a knife is so elite, so good, that it needs a special handling to use. maybe because of that special handling, the handler can only do 20% of the work of the guy ramming through his stuff rolling and denting and repairing his knife on the fly.

time... matters. the Olympic runner that crosses the line first but tears a tendon from the effort wins, not the elite athlete with a precise stride that holds back to ensure they don't get an injury.

knives can be fun hobbies. they can be relaxation tools where you sit back and smell the roses.. but as a tool.. tools are about productivity. the best tool is going to be the most productive, factoring in all things use, care, maintenance.. tools are also disposable.

if one tool is $400, and will last 10(x) and another is $20 and lasts 1(x) but does the same level of work until expiry, then for $400 the cheap one can be had 20 times making it 20(x) for the same money. so ideally the $400 one is best if you can replace components for longevity and long term "cheaper" operation over time.
in most cases of tooling, you pay for the best because you work out that the losses incurred by continually needing to replace the cheaper ones add up over time to show the cheaper one is more costly investment.
all this is ignored to the knife nerd community in general. Im a sucker for it too sometimes. (impinda)

lots of things to consider to determine "what makes the best knife" for real use.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 07:11AM
For the most part, it's woo and cargo cult science.

---------------------------------------------------------------------------------------------------------------------------------------

Bill22252 on YouTube. "See you space cowboy"

Resident Emerson Fanboi

Folding knives are fun, fixed blades are important.
Re: Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 12:06PM
Planer blades : 250, 1200, 15000 grit :

[www.youtube.com]

-250 works fine
-1200, not much difference
-15000 less resistance, not a lot (but surface now needs preparation)

This is a master level (word isn't strong enough) wood worker, anyone just mucking about in the out-of-doors who thinks they need those kinds of finishes, well that's just idle fantasy. You think people didn't build things with wood before modern abrasives.

How long do you think it takes to go from :

-250 to 15, 000 grit
Re: Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 01:16PM
Cliff,
I looked into what was a good EDC grit finish for my use. I had a hard time comparing edges. I don't think there is much of a practical difference. I can get #325 DMT Blue or Norton F India edges to push cut and whittle hair, and I can get Spyderco UF, 8k JIS, Surgical Black Arkansas to slice.
[www.cliffstamp.com]

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
Re: Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 06:02PM
I just timed myself sharpening one blade of my Leatherman Wave, and the main blade on my SAK Super Tinker. I did a full four stone progression, #90, #220, #1k, #8k. It took my 14 minutes to do both knives, that is 7 minutes each to get a mirror polish, arm-hair tree-topping edge.

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube



Edited 1 time(s). Last edit at 06/21/2020 06:03PM by jasonstone20.
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 08:13PM
Quote
jasonstone20
I just timed myself sharpening one blade of my Leatherman Wave, and the main blade on my SAK Super Tinker. I did a full four stone progression, #90, #220, #1k, #8k. It took my 14 minutes to do both knives, that is 7 minutes each to get a mirror polish, arm-hair tree-topping edge.

So.. how long if you stopped at the #220 progression..
going to drag our discussion from the youtube comments to here

Quote



Jason Daniel Stone
Jason Daniel Stone
13 hours ago
@knivesandstuff With the time, however for the 8k edge (Not really an 8k edge, the Norton 4k/8k stone he uses there, the 8k side is 3u, with is closer to 5-6k JIS) 35 min to sharpen, even on a fixtured system is a very long time. If you use scrubbing strokes the job with get done a lot faster, it was just a 1k, 4k, 8k three stone progression, I can knock that out in less that ten minutes if I want a shiny, pretty edge. If I 3-Step or Plateau Sharpen, I can get a 8K edge in under 5 min.



knivesandstuff
knivesandstuff
12 hours ago
@Jason Daniel Stone do you think your time for sharpening is an avg time for most people. do you think his time is wrong? or just not as good as yours? would other people be slower? so if you can get an 8k edge in 5min, what time would your 600grit edge be?



knivesandstuff
knivesandstuff
12 hours ago
@Jason Daniel Stone also. he factored in time to soak the stones which was required to do the 8k.. now of course, you might use stones that done need soaking. who knows. but its all time. you also then would need to factor in a similar test to see if your sharpening, being faster gets similar difference, or better.



Jason Daniel Stone
Highlighted reply
Jason Daniel Stone
12 hours ago
@knivesandstuff Ok, that makes more sense. You can however, speed up the time for your stones soaking by putting them under running water, cuts the time by half. Like you said, you could also use splash and go stones, or diamond plates.



knivesandstuff
knivesandstuff
12 hours ago
@Jason Daniel Stone So.. how long do you estimate your 600grit edge will take, if the 8k edge is 5min?




so going by 7min for your 8k sharpening.

you would get 14ft/m on the 8k edge. vs his 2.8ft per minute with his method of sharpening. if we assume you both got an equal quality edge for the given times.

this would place your 8k edge slightly ahead of his 600grit finish doing 12ft per minute.

now the question is.. can you sharpen to 600grit equiv in 4.2 minutes or less? if you can do it in 4.2 minutes you have matched your time cost curve, and so maybe you'd rather spend 7min for the extra longevity over 4.2 minutes because you get the same amount of work done, but less pause time.

but if you can do a real 8k in 7, I would be very surprised if it takes you 4.2 minutes to do a 600grit.
so out of curiosity.. how long will that take you?

because I can sharpen to 600grit DMT fine, very very fast. on an edge worn from cardboard.. its nothing.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 09:52PM
Quote
cKc
So.. how long if you stopped at the #220 progression..
5-6 min? Most of the work is done on the coarse edge, the #90 grit TASK Garden Hone.

Quote

now the question is.. can you sharpen to 600grit equiv in 4.2 minutes or less

I will check and see. I have a #325/#600 DMT DIafold.

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
Re: Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 10:10PM
cKc
I have both of the exact knives he used in the video. I used the longer of the two, the 4.25" Resilience. The stone is 1x4". It took me 49 seconds, including three cuts into the stone, to raise a burr and flip it, then 16 seconds to deburr so the blade was shaving in both directions. So total time was 65 sec. That is about a minute of sharpening time for one grit, on a steel, 8Cr13MoV, that people complain has a clingy, hard to remove burr. I did not use a micro-bevel.

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
Re: Sharpening Gain Vs Sharpening Time (again)
June 21, 2020 10:13PM
The technique I used is almost the same as Cliff's here, from 11:00 - 12:20:
[youtu.be]

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 01:27AM
thanks..

so lets assume your 7min to 8k is 14ft/min vs his 2.8ft per min
and your low grit is 2:30 about 1/2 his time.. which gives you 24ft/m

no matter how you look at it. if you want to be productive in work that does not require the physical precision of a high polished edge, then sharpening past a certain point is a highly unproductive return on investment.

no matter how you look at it.. if you were an employer paying for the time, you'd never ask someone to take that extra step to gain 60% cutting efficiency. actually.. in your case, in real life you lost 42% of your potential efficiency per day, by going to 8k, not the gain of 60% for 1 sharpening.

as I said.. not sure if people doing a lot of this stuff "work": with knives.


now.. lets say you open a few boxes a day with your knife, and the basic knife lasts you 8 weeks, and then 8k based on this lasts you 12.8 weeks.. well.. this sounds frkken awesome right? sure.. because the knife isn't doing anything so in that case you may well prefer to sharpen 1 time per 13 weeks over 8..

it will probably oxidize away in around 3 days though.. lol

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 06:16AM
cKc
Yes, I get that point. I am finding that the edges I take to 6-8k are not have the oxidation problem. That is one of the reasons when I tried a more coarse edge, I wasn't happy with them, they would just die on me, whether I used them or not. I agree, if you are doing work, sharp is more important than what grit it is sharp at.

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 06:19AM
cKc,
One thing that Alex didn't take into account was slicing sharpness. He measured push cutting. If he sliced, the lower, one grit #600 edge would also outlast the 8k edge, so there is even less benefit to the 8k edge.

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 07:18AM
hard to say on that front.. yes he sectioned off the blade so that he was only using one portion.. but that doesn't mean it was a push cut.

push cutting is being used far too much for what it is not. he might be push cutting sometimes, but he is not push cutting in general.

if your knife is not perpendicular to the cut for the cut, then it is not push cutting.

(1) in the picture is a push cut. he is using (2), same as a box cutter. box cutters are also almost never used as a push cut, but a draw cut, where the blade is always at an angle to the cardboard to perform the same cutting as you get with a slicing action. same reason people keep saying they are pushcutting toilet paper when they are not.. because they just don't have the sharpness for it, and are in reality draw slicing and using the edge aggression to do the cut. i think there is a major confusion about push cutting that keeps coming across that you have to be doing some large slicing/drawing action of the knife to be a slice vs a push.. not the case.



I feel like this is a topic that really needs to be addressed as it is so misunderstood, and these guys cutting may also not understand how them not even paying attention to "how" they cut will massively effect the longevity of the cuts on the apex.


almost no one is every truly pushcutting in a general sense for general use without needing a specific intent and purpose to do it. LOL

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 07:29AM
cKc,
Do you find it odd that a #600 edge would not have better edge retention than an 8k edge for cutting cardboard? Would the results be different if there was a 2" part of the blade was taped off? 3"? I am think there might be an issue with testing shaving sharpness as a metric for the sharpness of two different grits. Since shaving is mostly a push cutting event, as a 8k edge is going to have a better push cutting sharpness and less slicing sharpness, while the #600 grit is going to have more slicing sharpness and less push cutting. Wouldn't it make sense that a #600 grit edge would lose shaving sharpness quicker 8k edge? This is what I was talking about when I said my sharpness testing was flawed in the Plain Stropping thread. Or am I overthinking this?

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 07:39AM
its so hard to say. push cutting with a coarse edge is easily hair popping depending on how the finish angle direction is done. if the angle is inline for straight grooves then you end up with an edge kind of like a babers hair trimmer (not really) but this is how I visualize it in my mind. you have lots of pokey bits, and lots of thinner sections of steel in between from the gouging.. the gouged weak bits can be much thinner than your final polished bevel.. so push cutting is getting resistance, then popping from this mixture..

we don't really know how good he finished his edges. or what angle to the stone they were finished. did he finish the 8k to the same edge pattern?

when he finished the coarse edge, knowing you are pulling the knife for cardboard, you want to angle the stone to get an aggressive bite on a pull, but a sliding cut with no bite if you push forward.. there are lots of ways to get a variation on edge life.

draw cutting on an angle is a lot better than push cutting, but still more pressure on one spot than a slicing cut. coarse edges want slices with low pressure, not high pressure drag that will have more risk of compressing and folding over the apex which is much weaker

too many things can happen here.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 07:57AM
Quote
cKc
push cutting with a coarse edge is easily hair popping depending on how the finish angle direction is done.
This is what I was going to ask also, does push cutting depend on the direction of the grit pattern? Say you are cutting at a 45° to the work, and your grit pattern is at the same 45°, in the same direction? What if you are cutting straight down at a 90°, but your grit pattern is at 45°?

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 08:10AM
In general, when I say push cutting, I mean a triple-90, so there is no slice/draw. The reason that it means this way to me is that it is the hardest way to cut, you need the highest sharpness (of that type) in order to do it. Once you :

-use any non-90 angle
-use any draw

The sharpness requirement drops significantly and I was using this as a test of sharpness, so I wanted one which had the highest standard. The highest sharpness I had seen at the times I was fooling around with it was a 3" push cut on newsprint. That is a push cut on newsprint at 3" from the point of hold, this is with the grain of the paper. If you want even harder, do it cross grain the paper.
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 08:12AM
cKc,
I carry with me a GATCO Diamond Triceps sharpener (XC grit), a GATCO Ceramic Triceps (M grit), and a Lansky butterfly paddle sharpener (#325 and #600). The Lansky is like a 3" version, continuos surface, of a Blue/Red DMT Diafold. These are if I need to change the grit finish or touch up one of my knives, since I usually run sub 3 micron edges for a finish. These are real working grits, if you ask me. For some reason, the high polish edges work better for how I cut, and there is that oxidation issue I run into. I like coarse edges, I think that they can offer a lot more cutting ability and edge retention than most polished edges. I would like to just use a filed edge, I am practical/pragmatic and I like things simple. At the same time, I think the polished edges are attractive. I do find it weird that people want high carbide steels with high polished edges, this isn't a good combination of steel and grit finish. I am still trying to find out the EDC finish that works best for me, I just need to work out the oxidation issue. I really could use your and Cliff's input, along with everyone else here.






There is a bit of push cutting in draw, and a bit of a draw in push cutting.

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 08:19AM
the problem i have a little bit with what you want to achieve is that I'm not sure if you are worrying about the right things.

your knife oxidised to the point it can't tree top hair, so you want to crank up the finish, to reduce the oxidation so that it might tree top hair?
but when are you going to use that knife to shave? lol you don't actually need that sharpness that you lost via the oxidation.

you just said you are carrying a miniature sharpening army in your pocket.. so who cares if it oxidized a tad in which 3 seconds on a strop will correct? it seems that there is problems needing to be sovled that don't actually appear to be problems, and more just topical interest?

here is what it sounds like you need to do.

take a folder and mirror polish a 9dps bevel on it that looks amazing, then apply a 600grit 13dps micro bevel on. this is what you strop, hone and touch up for the next 6 months all the while retaining that nice mirror above that wont change grinning smiley each day just strop the knife for 5 seconds to remove oxidation

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 08:24AM


this is/was a daily user of mine.. looks kinda ratshit.. that's because I near zero ground it so the hollow is just a hint, and then I couldn't be bothered making it look fancy because its a user.

looks worn, but really the edge is not that far off the new edge.. dmt fine or x-fine, or Norton and strop.. the finish mostly doesn't matter if its done well and sharp.. but the only time I worry about its cutting ability is when I notice its not cutting what I need to cut anymore, then 5 seconds and its done.. i literally don't waste much time with arbitrary tests of sharpness. I'm too pragmatic for my own stuff and incredibly lazy to it.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 08:28AM
Quote
jasonstone20

Do you find it odd that a #600 edge would not have better edge retention than an 8k edge for cutting cardboard

First, to clarify, his data doesn't show that one of those edges have better performance than another. You can't draw conclusions from one trial run like that, if you are going to do that you might as well just have a computer pick two random numbers for each steel and use those for your conclusions. There is far too much variation in that type of cutting to expect stable results from one comparison :

As an example of edge retention as influenced by grit (PB has broke most of the images, but the description is what matters) :

[www.cliffstamp.com]

In general, very general, as you make an edge more coarse, AND, you are doing draw cutting, the edge retention will increase, IF, you are measuring sharpness by draw cutting as well. If you draw cut for the work and measure sharpness by push cutting, well that just makes no sense, it would be like seeing who had the best cardio for running by :

-making people run a mile
-then do a 1-rep max dead-lift
-repeat until you fail a 400 lbs 1-rep-max

It should be obvious that whatever you are measuring there it isn't who has the best cardio for running. You have just created some kind of weird bi-athlete.

Back to coarse edges, a real big problem with coarse edges is that most people can't actually sharpen with coarse finishes so they end up testing :

-a semi-dull, poorly sharpened coarse edge
-a decent finished fine polish

In that case, the fine polish could even outperform the coarse edge even on draw cutting. It would be like the World's Strong Man might beat the current 100 m sprint olympic gold medalist in a sprint, IF, the gold medalist has pneumonia. Imagine doing this but on grass vs a track and then saying something like "See a World's Strongest Man is FASTER than an Olympic Sprinter on Grass!" and then start talking about some nonsense about the hydrostatic bond created due to the surface tension of dew on the grass being broken more easily by the heavier Strong Man. Of course what you are seeing has nothing to do with track vs grass, you just showed if you get someone sick enough they can't perform well in physical events.

To start, the coarse edge should :

-shave arm hair with the barest touch of the skin, ideally above it
-push cut newsprint, an actual push cut 90/90/90, about 1/2"+ from the point of it being hold

Most coarse stones are in some state of being loaded, worn, or almost as bad, over ground. If you have a 100 grit stone, but you lap it on a ~600 grit abrasive, well you just made a ~600 stone which is actually going to rub more than cut because you just cut/wore the abrasive down.
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 09:27AM
Example edge i just made in a couple minutes.

Victorinox folder.
dark view edge, with edge destroyed by steel hone. changed to lighter background.
show the apex fully formed only on the coarse grit DMT stone..
showing all the hair that jumped off my arm.

you can see that when looking at the apex, you would not be able to tell this was coarse. not until you see the side scratch pattern.. this is 1mm view. i have no idea if this would pass cliffs paper test. i don't have any paper of any kind here.




edit: its actually hard to show the apex, because the light is just going around it. nothing to reflect off.

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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen



Edited 1 time(s). Last edit at 06/22/2020 09:29AM by cKc.
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 09:41AM
same edge. def cannot push cut tissue




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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 09:46AM
just for fun. coarse edge can still also #kebabstickcut reasonably cleanly as the microscope shows because you are not really pushing through but drawing through


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It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 10:05AM
Quote
cKc
your knife oxidised to the point it can't tree top hair, so you want to crank up the finish, to reduce the oxidation so that it might tree top hair?
but when are you going to use that knife to shave? lol you don't actually need that sharpness that you lost via the oxidation.

I am just trying to maximize high sharpness and push cutting ability. I have knives that have been sitting for a month, that have low angles and high polishes, 6k-8k that maintained tree-topping sharpness. I made a YouTube video that is uploading right now, I will post it here once it is done. For some reason, it stopped at 10 min, but I had shown what I was trying to show. I am also trying to figure out why I have an intermediate issue with some edge angles and some grit finishes. I am trying to find out the best EDC edge angle and edge finish for me, and one that is resistant to oxidation, as because sometimes my knives do not get used for a few days (this is because I carry multiple knives, and don't always have anything to cut). This gap in use, the knives being carried but not used, is a part of my usage pattern and is an important factor that needs to be accounted for. I am way past what I need as far as what is practical in use. I have only used a small box cutter for a week, and it did all the cutting I needed. I am trying to explore the limits, and find out what the limits are.

Quote

you just said you are carrying a miniature sharpening army in your pocket.. so who cares if it oxidized a tad in which 3 seconds on a strop will correct? it seems that there is problems needing to be sovled that don't actually appear to be problems, and more just topical interest?

It isn't what I have available to me, it is reducing extra steps in use. I have different blades on me that I can use if one isn't working for some reason, including serrated edges and scalpel blades.

Yes, I am not trying to solve an overall practical problem or issue, sorry if I wasn't clear on this. I am trying to explore and find the limits of what is able to be done, how far you can practically have a high sharpness edge, and what to expect from the edges and grit finish.

Quote

take a folder and mirror polish a 9dps bevel on it that looks amazing, then apply a 600grit 13dps micro bevel on. this is what you strop, hone and touch up for the next 6 months all the while retaining that nice mirror above that wont change grinning smiley each day just strop the knife for 5 seconds to remove oxidation

I have a thread I started about that (I was looking into it and found a BladeForums thread that talked about it):

[www.cliffstamp.com]
[www.bladeforums.com]

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"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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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StoneSharpEdges

Jason D. Stone on YouTube
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 10:13AM
cKc,
Your edge should pass a 3x90° newsprint edge. I have gotten a filed edge to pass that test and slice cigarette paper. I was trying to get it to push cut cigarette paper, but I failed. I came close, however. I have this documented somewhere, let me find it.

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 10:19AM
Quote

It isn't what I have available to me, it is reducing extra steps in use. I have different blades on me that I can use if one isn't working for some reason, including serrated edges and scalpel blades.

Yes, I am not trying to solve an overall practical problem or issue, sorry if I wasn't clear on this. I am trying to explore and find the limits of what is able to be done, how far you can practically have a high sharpness edge, and what to expect from the edges and grit finish.

yeah. so its not about need, its simply about the determination of what can be done, and what will happen, which is cool. its an experiment.

Quote

I am trying to find out the best EDC edge angle and edge finish for me, and one that is resistant to oxidation, as because sometimes my knives do not get used for a few days (this is because I carry multiple knives, and don't always have anything to cut)

sure.. but again.. experiment is fine. but realistic patterns of use tell me that if you determine that 8-10k finish which takes minutes or more of extra work sharpening has a singular purpose to prevent oxidation that can be resolved with seconds of effort at the start of the day, then I'm just calling it counter productive. good to know, but counter productive from my personal use system.

what if you cut something mildly acidic for example, then the extra effort spent is gone. etc etc.

what is the highest grit you have in sharpening equipment.

you are testing stainless steels which is just slow.

if you want to measure the effects of polish against oxidation, then the simpler alternative is to go and buy 3 carbon opinels or similar cheap.. old hickory paring knvies etc.

set each of them to a 12dps bevel of a size easy to see by eye. finish one at 200, 1000, 30k finish, and then leave all 3 in the same spot in a room for a week and using the microscope, buts some form of moderately accurate edge sharpness test, compare the differences.. and do that multiple times.

i think the methods you are using to determine what you want to know will not ever get a satisfactory answer.

but there is a simple guarantee. the more finished the steel. the more sealed the pores of the steel are, and the less surface area (including all gouges crevasses etc) that you have, the more resistant to corrosion and oxidation.. you also have to take care to consider that the reason stainless steel is stainless is because it forms an oxidation resistant barrier so thin you simply cant see it, even on most microscopes..
so consider that residues of sharpening oil, mineral oil, abrasive, skin grease etc etc in amount you can't even consider can all increase or decrease oxidation in a way that is not obvious.

unless you can saturate all the blades in a decontamination solution how much randomness could be occurring in regards to why it is oxidation or not, or if that is the real cause, and not something else that has slipped your mind about use patterns.

i guess you have a lot of work ahead.

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 10:20AM
Quote
jasonstone20
cKc,
Your edge should pass a 3x90° newsprint edge. I have gotten a filed edge to pass that test and slice cigarette paper. I was trying to get it to push cut cigarette paper, but I failed. I came close, however. I have this documented somewhere, let me find it.

I really need to go buy a newspaper grinning smiley

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 10:21AM
Filed edges:
[www.cliffstamp.com]

Here is a thread were I get my Spyderco Tenacious and Opinel cutting cigarette paper with a #220 edge and a filed edge. ShaperAndMower also posted a video of the standing cigarette paper cut test, that I find to be one of the hardest tests for push cutting:

[www.cliffstamp.com]

------------------------------------------------------------------------------------------------------------------------------------------------------
"Gotta love living in 2019 baby, (63rc too soft on a production knife)"
--Shawn Houston
__
"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
------------------------------------------------------------------------------------------------------------------------------------------------------
StoneSharpEdges

Jason D. Stone on YouTube
cKc
Re: Sharpening Gain Vs Sharpening Time (again)
June 22, 2020 10:29AM
passivation

you could examine ways to enhance the passivation of the apex, without dulling the knife..

I'm curious to see if you dip a knife immediately into a mild acid after forming the apex if this itself has any dulling activity, and if then the forced passivation increases the longevity against further oxidation.

either way, looking at what you want to find out. studying more about the topic would be a good place to go

----------------------------------------------------------------------
It's not Cliff, its Dr Stamp
#kebabstickcut, it's a thing - make it happen
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