How Sharp is Sharp Enough?

I want to clarify that I wouldn't expect to spend that kind of time on sharpening in the field. I use the same Diafold sharpeners as you. In my camp pack I carry XXC, XC, C, F XF and XXF. If I'm going light and will be out for while, I'll carry just the course and fine.


I use a 20x and 30x loupe

And just to let you know how stupid I get.... my final strop is done on 60,000 grit lapping paper...:o


Rick
 
messer454 said:
what power loupe?
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I use an 8x but the power isn't that important. A 6x or 10x would work just as well. I actually have a 10x stereoscopic field microscope on the same bench that I do my sharpening/stropping on, and use it occasionally. Looking at the striation pattern of different grits gives you a very exact way to determine how polished an edge is.
 
The effect of blade finish and blade edge angle on forces used in meat cutting operations

Abstract

"Meat cutting causes a much greater incidence of upper extremity disorders than industry averages. Grip forces and cutting moments in meat cutting operations can be very high. Recently published studies indicate that the blade sharpness can significantly affect force exposure during meat cutting. Two attributes that have not been investigated with respect to force exposure during meat cutting are the effect of blade edge angle and blade finishing after sharpening (honing and polishing). This study investigated the effect of three blade edge angles and three post-sharpening finishing protocols on the grip forces and cutting moments exerted by professionals during two different meatpacking operations. A fine polish finishing protocol significantly reduced cutting time by 25.3%, mean grip force by 21.2%, and mean cutting moment by 28.4% over a coarser finishing protocol during one of the operations. No significant differences in the exposure variables were found between the blade edge angle conditions."

Raymond W. McGorrya, Peter C. Dowdb and Patrick G. Dempseya

Liberty Mutual Research Institute for Safety, 71 Frankland Road, Hopkinton, MA 01748, USA

bAnago Ltd., Hamilton, New Zealand
 
Sharp enough is when any additional sharpness would add risk of injury. No, I have never actually seen that be an issue.:D I did notice though, that one time I was cutting open some plastic grocery bags, and the knife cut through them with such ease that I thought,"This knife could be dangerously sharp to someone not properly instructed or experienced". So depending on the situation, a knife could be too sharp for one person, but still just sharp enough for another.
 
I'm afraid I dont understand the question:confused:

I've recently began taking a minimalist attitude toward sharpening. Along those lines, the coarse/fine DMT combo is about the best thing going. Fine edges last longer for a wider variety of cutting. However, if you have a dedicated knife for cutting rope, string, cardboard, or other soft material, a coarse edge can last a long time.
 
Mannlicher said:
to me, "sharp enough" means that for the blade in question, and the task at hand, the blade is sharp enough to easily and safely accomplish that task.
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One of my sharpness tests is to take a knife I have been sharpening into the kitchen and slice up a tomato. I can tell by how easily this task is done whether the knife is 'sharp enough' or not. I had a knife that wasn't shaving arm hair, I tried the tomato and it really wasn't good enough. Once I got it 'shaving sharp' it also sliced tomatoes well. My experience is that a knife that cannot shave arm hair will be less of a pleasure to use on normal tasks than a knife that CAN shave arm hair. My carbon Opinel knives are the best tomato slicers I own, they beat my serrated steak knives quite easily - they are sharp enough!

I have been playing with many of my knives while watching TV, mainly sharpening until they have a sharp and polished edge that can smoothly shave arm or leg (I sometimes run short of arm hair to test on) hair. I have managed to get the little blade that is on the LM Squirt S4 'shaving sharp', it is too small to cut tomatoes but I know it is sharp enough for any tasks that it can cope with. I have stropped some knives enough to make the edges convex and polished like a mirror - they tend to shave very smoothly and not feel all that sharp, except that the hairs fall off really easily so they MUST be sharp.

I use an edge trailing scrape across my thumb nail with the knives to see if it will scrape the nail at all - if it does then there is a burr. This is a pretty easy test to find out if you are sharpening correctly.
 
I dont really have anything to add but man I keep reading post praising the DMT C/F diafolds and I just cant get the hang of it. It ruins the edges on my knives every time. I have to use a stone or sandpaper. WTF am I doing wrong???
 
Kinda depends what you're cutting, in addition to the qualities of the steel and of course the geometry of the blade. A well-known Yukon outdoorsman of my acquaintance used the coarsest hone he had to sharpen his D2 blades for field dressing. That toothy edge would shear through joints like a chainsaw. D2, and S30V have rather large carbides, I believe. High carbon steels with smaller carbides, such as 52100, will take a much finer edge, but won't necessarily outperform that toothy edge on D2 when it comes to cutting hide and sinew (though you can hone D2 and S30V to a very highly polished edge). The hone will make some difference, too. I use DMT diamond hones to put a highly polished edge on most of my blades, but I inherited an ancient Black Arkansas hone that imparts an amazingly sharp edge on high carbon steel blades. I figure it creates micro-micro serrations. So, it all depends...:)
 
Diamond hones cut rather fast for their grit size. My approach was to get a combination Medium(400)/Super-Fine(1200) EZE-Fold hone from EZE Lap. If I want to leave some serious tooth on the edge I just use the 400-grit. If I want a smoother push cutting edge I finish with the 1200 grit. This is my traveling hone.
 
vickmacky said:
I dont really have anything to add but man I keep reading post praising the DMT C/F diafolds and I just cant get the hang of it. It ruins the edges on my knives every time. I have to use a stone or sandpaper. WTF am I doing wrong???
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Your using too much pressure or they have not broke-in yet. The coarse side should produce a edge that shaves arm hair with ease.
 
I think the better question is how do you explain sharp? From 120 grit to 100,000 grit I can think of probably 100 different levels of sharpness and equally related feel. Even with the same grit stone I can think of several different levels of sharpness and how you can change it simply by the amount of pressure your using.

I know how a edge feels at almost any level from a number of abrasives on countless steels, this information has been aquired over years of sharpening and tons of trial and error with different abrasives.

So how do you explain sharp to someone when its something that can only be seen and felt?
 
if its my field knife i just speed sharpen it, i dont need to do more than chop. if its my carving knives i use the scary sharp system. i start with 1200 grit and work my way to 4000 grit.with the rest of my knives i generaly use a strop i made out of an old belt,i took a 3inch wide pine wood and on one side glued a piece rough side up and on the other side smooth side up. i use jewelrs paist with the rough side to hone a nice edge and the smooth side i use plane to keep the edge.
 
Sharp Enough= To be able to cut what you want to cut, the way you want to cut it.
 
Sounds good but still explains nothing. I can get a sharper edge than most factory edges with a coarse diamond but I like a mirrored 1 micron edge for most all cutting, does this mean I go too far or are they not going far enough? most consider a factory edge sharp enough thus why I ask.
 
knifenut1013 said:
Sounds good but still explains nothing. I can get a sharper edge than most factory edges with a coarse diamond but I like a mirrored 1 micron edge for most all cutting, does this mean I go too far or are they not going far enough? most consider a factory edge sharp enough thus why I ask.
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I have to disagree with you there. Here on bladeforums your in the world of knife knuts, where it is the exception that one would be satisfied with a factory edge and I think the vast majority of those who frequent the forums would agree.
You ask if your sharpening to much? Well that's up to you isn't it....
If your not satisfied with any particular edge then you continue to refine that edge until you are. At that point its "sharp enough". Only you can decide when your happy with how an edge performs the task at hand. I'm not sure what else you are looking for. No edge profile/geometry/level of polish/etc... is right for every knife or every task so I'm not sure what your looking for,
 
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