Knife edge sharpness - when is enough - enough?

U

UR7knife

Joined
Dec 9, 2025
Messages
12
Hi guys,
A Q rose in my pondering mind:

I have folders - robust, and dainty
I have fixed blades - Choppers/ Survival, bushcrafters, and dainty

My assumptions are:

For dainty blades,
I assume they are supposed to do household/ office chores, cutting through soft/ dainty material, and intermittently though the day/ week
So, thin geometry, flat/ hollow primary grind, 15-20 deg secondary grind, stainless - sharper is better, and will probably hold an edge for a long time

For more robust folders and fixed,
I assume they are tasked with shed/ garden/ back office tasks - such as cutting through cardboard, zip ties, bush pruning, etc - a daily use and a bit more intense to the dainty ones
So, Not so thin geometry, a bit bigger in size and weight, more robust in locking mechanism (folders), Flat/ Hybrid primary grind, stainless, 17-22 deg secondary grind - here sharpness hits a peak where sharper means it will lose its edge faster, and will not bring any appreciable advantage to being not hair whittling sharp, just paper cutting sharp..-Or it will necessitate improved wear resistance - which means better metal/ heat treatment and so higher price tag.

For Outdoors/ bushcraft knives,
I assume that between making fire/ cutting small branches, feathersticking, and such tasks, the preferred primary grind is flat/ saber/scandi, and the secondary grind (when not truly scandi) is flt, with 20-25 deg, flat/convex.
Now cutting paper sharp is not the point. It rather has to be corrugated cardboard sharp, to perform all these tasks without losing performance.

For shoppers, well.. the angle of the secondary grind is even steeper 22-30 deg, and/or switching to convex profile (scandi or full), where the secondary grind/ if there is one, is trying to present as much material behind the cutting edge as fast as possible.
Here such knife should be tire rubber sharp, or very thick cardboard. Anything else is overkill, and would not introduce an appreciable advantage.

My Q is:
Is the reasoning behind what I'm suggesting sound? (right sharpness for the right task) ? -OR am I completely off? -And if so, please let me know your thoughts in detail..

Cheers
 
Stop before you get to here.

worn-knife-jpg.1632163
 
edge angle is user dependent. I use my large brush blades around the yard at 12-15 degrees per side (dps). Even kitchen knives that cut chicken bones are typically no more than 20 dps. I’ll go to 22 dps for a softer generic stainless.
 
SOLEIL said:
if i can't shave with it i don't carry it
Click to expand...
So..basically, you don't carry anything over 250 gr (8.8 Oz), and over 10cm blade (~4").
Apropos - when out & about, I carry at least one medium size food prep knife, which I don't keep as sharp as described, since its easier to gut a fish/ or clean game without piercing their gut inside them when cleaning, and this type of sharpness is a hindrance when de-boning a carcass of filleting a fish - but this is just me.., and a chopper, which I don't keep "shaving sharp" since I'm going to wail on it when chopping stumps for kindling, where this sharp's going to chip or break or bend first time I baton it into wood, especially if there's a knot in it.

I hoped for a more serious approach.
 
UR7knife said:
So..basically, you don't carry anything over 250 gr (8.8 Oz), and over 10cm blade (~4").
Click to expand...

The member didn’t say that. I interpreted it as “if it won’t shave hairs”, not “shave my face in the morning”. Usually arm hair is what we mean around here when we say shaving sharp.

UR7knife said:
and a chopper, which I don't keep "shaving sharp" since I'm going to wail on it when chopping stumps for kindling, where this sharp's going to chip or break or bend first time I baton it into wood, especially if there's a knot in it.
Click to expand...

Interesting. You know this from experience? Which knife? I make choppers which I grind to very thin edges, around .016” behind the edge, supported by subtle convex geometry. I sharpen them so they will slice paper cleanly and are shaving sharp. Edge is around 20 dps.

And they stay that way a long time even after processing tons of wood.

UR7knife said:
I hoped for a more serious approach.
Click to expand...

If you keep an open mind you might see that you have been given serious answers.
 
Well except for Danke42. He’s right but I think he was also being funny. Maybe.
 
UR7knife said:
So..basically, you don't carry anything over 250 gr (8.8 Oz), and over 10cm blade (~4").
Apropos - when out & about, I carry at least one medium size food prep knife, which I don't keep as sharp as described, since its easier to gut a fish/ or clean game without piercing their gut inside them when cleaning, and this type of sharpness is a hindrance when de-boning a carcass of filleting a fish - but this is just me.., and a chopper, which I don't keep "shaving sharp" since I'm going to wail on it when chopping stumps for kindling, where this sharp's going to chip or break or bend first time I baton it into wood, especially if there's a knot in it.

I hoped for a more serious approach.
Click to expand...
"Only sharp knives are interesting"

ps. you're being unnecessarily argumentative, imo. I hope you do not melt down.
 
David Mary said:
I think you might be overthinking this. Sharpen every knife to where it slices paper cleanly. And then use it for tasks its given design will support.
Click to expand...
You can use a STD paper as test for an light duty/ office knives, but you can also use telephone book paper, which is more demanding, or cutting through a paper tower which is even more demanding (I've seen all three serve as sharpness tests, as well as shaving your hand, and hair splitting/ whittling).

So the pursuit for sharpness can be to infinity. The establishment of a good system where if you get a new knife, you know what to expect from it as far as not only performance but F&F and sharpness, is a good way to standardize it in a way where two people who never met before but love knives,might converse using the same terms.

In terms of F&F, for lightweight/ light tasks hot-spots are not as crucial as for chopping wood, or batoning a knife. you will probably not get calluses from shredding paper, or opening boxes. So the weight F&F in determining the quality of a knife and fitment to an intended task, grows when the knife and task become more taxing on the body.

Same as shock absorption/ dissipation by the knife handle. for food prep it is somewhat noticable, for choppers it can be crucial.

I know this after manufacturing handles for four sore bought knives, and have gotten compliments for getting them to conform better to the hand (I worked with G10, Micarta and CF so far).
I also have reshaped some store bought knife profiles, to much more usable (for me), and those who saw what I did tried them and understood why I did it.

I'm not someone who doesn't have any "skin in the game"' although I'm a hobbyist, i.e., I do things for myself and friends, but I don't make a living out of it.

Now, I'm trying to find out if others tought bout the minimal requirement for shrpness, depending on the kind of knife and task.
 
UR7knife said:
So..basically, you don't carry anything over 250 gr (8.8 Oz), and over 10cm blade (~4").
Apropos - when out & about, I carry at least one medium size food prep knife, which I don't keep as sharp as described, since its easier to gut a fish/ or clean game without piercing their gut inside them when cleaning, and this type of sharpness is a hindrance when de-boning a carcass of filleting a fish - but this is just me.., and a chopper, which I don't keep "shaving sharp" since I'm going to wail on it when chopping stumps for kindling, where this sharp's going to chip or break or bend first time I baton it into wood, especially if there's a knot in it.

I hoped for a more serious approach.
Click to expand...
to me the sharpness is never a hinderance. the skill of the user is. every tool effectiveness ultimately depends on the skill of the user. that's just the way of things and always has been
 
i sharpen free hand , and i only own simple steel(s) knives , so i can't talk about angles or so and i keep mute about space steels i don't know. i use a natural stone, i'd say medium , finest are dedicated to my carving knives...
well i sharpen then i hone on a "loaded" leather or a piece of birch fungus till i shave my wrist hairs (i don't want to shave my all arm!!!!!!!!)
 
David Mary said:
The member didn’t say that. I interpreted it as “if it won’t shave hairs”, not “shave my face in the morning”. Usually arm hair is what we mean around here when we say shaving sharp.



Interesting. You know this from experience? Which knife? I make choppers which I grind to very thin edges, around .016” behind the edge, supported by subtle convex geometry. I sharpen them so they will slice paper cleanly and are shaving sharp. Edge is around 20 dps.

And they stay that way a long time even after processing tons of wood.



If you keep an open mind you might see that you have been given serious answers.
Click to expand...
I'm trying to - I presented a specified approach and have gotten simplistic answers so far, for the most part. The convex edge is one that appears in what I've described for choppers, and bushcraft knives. I should think that after some use, it would have difficulty in shaving hair of your arm, while still being plenty sharp for the tasks you need it to perform. Which brings us back to my point from the other side: when would you stop and re-sharpen? I would think it would be when it falls short of performing the tasks you want it to, or when it starts needing more effort to do so. So there is a lower sharpness limit, depending on the task and knife class, and for all practical purposes, let's agree that the higher limit is 'shaving sharp". I propose the lower limit is different and depends on the task and knife class, and not on the hair of the hand.
 
flexo2 said:
i sharpen free hand , and i only own simple steel(s) knives , so i can't talk about angles or so and i keep mute about space steels i don't know. i use a natural stone, i'd say medium , finest are dedicated to my carving knives...
well i sharpen then i hone on a "loaded" leather or a piece of birch fungus till i shave my wrist hairs (i don't want to shave my all arm!!!!!!!!)
Click to expand...
It seems to be a general indication for most, but I personally don't have hair to spare.
I recon using a thin paper (like a page from a newspaper, or telephone book), or the paper towel test, would serve you as good, without having to sacrifice your hair.

As far as metals go, I am not concerned with that, since the same steel with good/bad heat treatment would behave very differently, but the blade geometry of two different steels, and if they conform to what it must do, will behave reasonably the same. The main difference, would be the sharpening frequency, and maintenance (protecting when not in use).
 
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