When do you say "That's sharp enough."?

Ever since I got a knife to slice and pushcut t.p that is the level or sharpness I shoot for. I have never been able to treetop hair, I don't know if it's technique , or if the knife just isn't sharp enough, but for me a nice clean cut with no snagging through t.p. is enough for me. I sharpened a knife for a coworker last week, and gave it back to him on Wednesday, I knew better than to put "my edge" on it but I did it anyways, long story short, 2 guys both cut their fingers wide open , and I was asked to never sharpen a knife for anyone again..:D, both guys said they didn't even feel they had been cut until they felt the blood dripping off their fingers...

Gonna add, I usually just go for ^this level of sharpness on my higher end steels, With say s30v , I'll mirror polish it, but I won't put as much effort into a knife that will lose the edge fairly quickly IMO it's just a waste of time, If its not a "super steel" cleanly slicing phonebook paper is good enough. I also use Murray Carters 3 finger test to check my progress and my sharpness as well.
 
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Allen R. said:
Ever since I got a knife to slice and pushcut t.p that is the level or sharpness I shoot for. I have never been able to treetop hair, I don't know if it's technique , or if the knife just isn't sharp enough, but for me a nice clean cut with no snagging through t.p. is enough for me.
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I think of them as different kinds of sharpness. I have some knives that can treetop hair but can't slice TP. Both edges are frickin' sharp, but they cut quite differently.
 
KennyB said:
Yeah, but I think what we're talking about here is when your real intended purpose is just to get the knife as sharp as possible with whatever your desired finish is. Coarse, balanced or polished I think most of this is talk about apex refinement, getting it as sharp as you can on the final honing process--and at one point you go "Okay, that's enough..."
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I go by a very simple process - raise a burr, flip, remove, and strop on plain paper. I might strop with an abrasive as well, but almost always finish on plain paper - "that's enough". Whether I come off the 320 grit sandpaper or something a bit more refined, a polish/burnishing with plain paper is a great final step. It takes it up a step and reveals any left over burrs.

KennyB said:
The interesting thing though, at the end yousay that for everyday use something that falls into the middle does the best job across a wide range of material and I think that's true. I've also read that on the DMT website reccomending their 600 grit hone for the "balanced" finish," also in Smith's manuals, and in countless knife manufacturer's manuals. So like, in some ways it's great to invest all the thought and evaluation into what edge is going to work best for whatever use, for most people who just want an everday use edge, it's spelled out in quite a lot of places that a medium finish may be best for that. It seems however that a lot of people want to buck traditional wisdom and see big numbers on the grits, people using all sorts of strops and compounds, and thinking that high polish is directly equivalent to an edge being "sharper"...
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I have to believe it comes down to use and how quickly folks can touch it up. If your process involves a handful of minutes every single night following a day where you used it at all, you'll quickly tire of that routine (or should). If your edges see relatively little use, or you're cutting materials for which a more simple process is unacceptable, this scheme makes more sense.
 
Allen R. said:
Ever since I got a knife to slice and pushcut t.p that is the level or sharpness I shoot for. I have never been able to treetop hair, I don't know if it's technique , or if the knife just isn't sharp enough, but for me a nice clean cut with no snagging through t.p. is enough for me. I sharpened a knife for a coworker last week, and gave it back to him on Wednesday, I knew better than to put "my edge" on it but I did it anyways, long story short, 2 guys both cut their fingers wide open , and I was asked to never sharpen a knife for anyone again..:D, both guys said they didn't even feel they had been cut until they felt the blood dripping off their fingers...Gonna add, I usually just go for ^this level of sharpness on my higher end steels, With say s30v , I'll mirror polish it, but I won't put as much effort into a knife that will lose the edge fairly quickly IMO it's just a waste of time, If its not a "super steel" cleanly slicing phonebook paper is good enough. I also use Murray Carters 3 finger test to check my progress and my sharpness as well.
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This is exactly why I give a stern warning to everyone I sharpen knives for. Most people are not accustomed to a truly sharp blade and tend to get careless with them. "Be careful, it's sharp." :D
 
HeavyHanded said:
The above falls into line with my philosophy. Intended use determines edge finish determines longevity. Have personally experienced rapid edge failure on high polished knives under certain applications, so gave up long ago on a "one edge works for everything" mentality. A toothy edge is not a polished edge gone a little dull. I consider it the process of sculpting formations into the edge that will interact with whatever I'm cutting to best advantage. Some materials will want no formations, some will want aggressive formations. My theory is based on pressure at the edge - if a coarse draw cut will part a given material with less pressure that edge will last longer. If a polished push cut will part a given material with less pressure that edge will last longer. For EDU something in the middle will do the best job across a range of materials.
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Like minds think alike I think. Its often times easy to blame the steel. Oh its a crap steel is a common thing you read or its not the best edge keeper. If many end line users are like my wife they don't seem to get that you can't expect any steel to keep an edge if you cut ceramic pot, and glass plate, and sand, and dirt, and grass and whatever else is in front of the blade edge as you use it! I see that at deer camps by the edge use ignorant too not just in women's hands such as my wife's:D

Its often you see what most would deem, 'unfit or inadequate knives' at some camps. Yet they work over and over and over for those using them. Why? Sometimes someone would show with a fancy new knife but nothing seemed to replace what they preferred. I saw a lot of those Buck Kalinga models out there in the Oark area and other Buck knives. Lots of Buck 110 models in deer hunters hands also, many being used start to finish on a buck or their limit every year going back some years too! Funny how that so called bottom of the barrel 420HC crap steels seems to perform pretty good for those good ole boys ain't it? ;) Maybe it has something to do with the optimum edge geometry and primary grind for the task? That may be part of it but you know the most of it is that the guy using the thing has enough sense not to cut sand, not to cut dirt, not to roll the carcass he is skinning around in said sand or dirt while doing the job and he does other little things like parting the hair back to make cuts that don't tax the blade edge unduly.

In other words he is in touch with his edge sense and he is right there present at that apex in his awareness not just blowing on the fur but down to the hide right there in the experience using the edge as its supposed to be used, guiding following, clearing the way for it as it nears obstacles all in tune with each other, fingers and hands as they clear the way one for the other. A knife nut can almost get a tear in his eye to watch a good ole boy in action using the knife he carries. Its truly a beautiful thing to watch when it is a skilled and seasoned master wielding a blade isn't it. Its not just a dance in sword play to be so masterful and not everyone gets that or cares to.. Compared to some of the slop jobs by the unskilled or uncaring edge users I've witnessed at various places from West Virginia, to Colorado, to Alaska to Oklahoma and Arkansas the contrast tells a lot about edge keeping vs need for some super steel. Its easy to cuss the POS blade as you roll the hide around in every last thing there besides skin and hair but in the end it was never the knife or the steel or even the type of edge to blame for the poor edge keeping! Ah, don't get me going. Its a good thread tho. These things need to be reminded to people using the tools they abuse. Kinda like paving the road for a smoother longer life for the car. Like that for the edge too in uses if you look at it that way.
 
HeavyHanded said:
I go by a very simple process - raise a burr, flip, remove, and strop on plain paper. I might strop with an abrasive as well, but almost always finish on plain paper - "that's enough". Whether I come off the 320 grit sandpaper or something a bit more refined, a polish/burnishing with plain paper is a great final step. It takes it up a step and reveals any left over burrs.



I have to believe it comes down to use and how quickly folks can touch it up. If your process involves a handful of minutes every single night following a day where you used it at all, you'll quickly tire of that routine (or should). If your edges see relatively little use, or you're cutting materials for which a more simple process is unacceptable, this scheme makes more sense.
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I've actually found myself just allowing my knives to dull more now. Gives me a better sense of how they actually wear, and then maybe once a week or whenever I'm bored I take them out and touch them back up--supposing I haven't completely wrecked the edge that is. I guess that's almos ta different question that you could accompany with "sharp enough", what is "too dull"?
 
Depending on the grind, I'll take 'em to 6000 grit either on waterstone or belt then plain or treated leather.
I'm happy when they'll shave arm hair easily.
I've done some to a higher level of refinement - but I can't get there consistently, and it doesn't seem to do anything for edge holding or for cutting ability beyond the initial sharpness test - so I don't push it anymore.
 
KennyB said:
I've actually found myself just allowing my knives to dull more now. Gives me a better sense of how they actually wear, and then maybe once a week or whenever I'm bored I take them out and touch them back up--supposing I haven't completely wrecked the edge that is. I guess that's almos ta different question that you could accompany with "sharp enough", what is "too dull"?
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That's another good question. Also, what are you looking at in terms of labor to get it back into shape. I recently let one go for about a month and a half, took some micrographs, and touched it up.
http://www.bladeforums.com/forums/s...econditioning-a-worn-edge-(with-micrographs!)
I am still a bit amazed that it could manage to shave some arm hairs even though it looked to be completely hammered.

I generally touch up more than that, but it all depends on what I'm doing. Since I started selling my sharpening widget, I give a few swipes on every one I sell as part of QC - checking for sharp spots, even surface, consistency of the compound etc. Unless I allow it on purpose, my knives never get dull anymore. Left to my own devices I won't touch my EDU more than two or three times a month, and that just a few swipes on the board.
 
U want crazy looks do the 3 finger test in front of non knife people the looks r priceless!
 
At least my wife now don't cut on plates etc. that she now appreciates the edge I put on her knives :D. Yeah, I'm a happy man!

@Martin, the washboard + 3 layers of paper + black compound followed with plain paper is what I do for her knives.

@Allen,
Last night we (me & wife) just had a talk & she said the way I test (3 finger or just the thumb along the edge) gives her scare ;).

To stay on topic, all my EDC must be capable of shaving my face clean. Sometimes almost there, a bit painful, so I need to refine it further. Bluntcut's 52100 so far comes top in term of smoothness in shaving :thumbup:
 
I now polish my primary bevels to a mirror shine. I then micro them with my SM brown stones. This seems to give them the polish easy cutting edge, but has some bite, to the very apex. This seems to split a lot of differences for me. BTW, these edges with treetop, cut news paper, plit your fingers on a three finger test, shave, and whatever else I need them too. I like these........for now.
 
I'm whittling hairs now. Not as easy as I would like, but the feat has been accomplished.
 
Joe Duder said:
I'm whittling hairs now. Not as easy as I would like, but the feat has been accomplished.
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Congratulations :thumbup: It only gets easier with time, soon you will have a preposterous array of hair whittling knives until the addiction wears off...
 
This thread went from a practical "When is it sharp enough?" to "How sharp can you make it?" discussion.
 
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For a working edge: if it will catch on a thumbnail at 45 degrees all along the edge, from heel to tip
For "sharp": if it will cleanly slice newsprint
For ultimate: if it will whittle a hair (note: I never take an edge to this level, only for demonstration purposes)
 
I have backed off the over the top polished edge approach...for everyday knives it just doesn't make sense. for a straight razor, yes you want comfortable shaves, for working knives, hell a double sided norton combination india followed by stropping with Chromium oxide is plenty sharp. Sometimes I'll knock out a quick edge on 2x72 belt grinder with a worn 220 grit then finish on white crock sticks..again pops hairs right off the arm and is plenty sharp.
 
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