Is too sharp a real thing?

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NeedItCheaper

Joined
Jun 17, 2012
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I've heard if a knife is too sharp it will dull faster because the edge is too thin and will fold or chip easier. Thus, too sharp. Any truth to this and is there an ideal sharpness for maximum edge retention? For context I'm using a Mora Garberg to cut pine wood. No chopping or batoning, just carving and feather sticks.
 
Depends on the geometry and the steel, but some experiments have found that knives sharpened below BESS 150 or 200 quickly dull to around BESS 150 or 200 and dull more slowly after that. I'm afraid I have lost the links, but I think I found them from the Edge-On-Up web site, or maybe the related forum.

It's also easier to cut yourself with knives that are literally razor sharp. Nevertheless, some people like razor sharp edges.
 
How sharp is sharp enough? That is the 64k question. For me 325 dmt one and done.in the kitchen and for my edcs. Except for the santoku that gets the 1200 treatment. I have refined edges up to a 30 k shapton. And lapping films pastes etc. But I find a toothy edge works fine for me. Ask 10 people and get 10 different answers.
 
I've long viewed shaving-sharp edges as something nice to see when an edge is first sharpened or tuned up - it's a good indicator the edge is fully apexed and as keen as it can be. It's also a good gauge for how sharp a particular steel can be made, and with what tools or abrasive types - so you can learn something there in making it as sharp as you possibly can. But I've also known it's a certainty the shaving sharpness isn't going to be durable in most typical uses for a knife and will likely disappear in the first cut or two. With that said, the best gauge for 'sharp enough' is better viewed in how the edge behaves after the shaving sharpness goes away. If it's still working well at that point for the task being done, then it's 'sharp enough'. And better still, if it's durable and lasting in that use.

There needs to be some practical balance between the time & effort spent to maintain an edge at a certain sharpness, and the amount of practical use you get out of it before its sharpness degrades to the point it needs touching up again. If you find you're getting tired of too-frequently tuning up the edge to keep it working well, then you'll start to realize how your expectations for sharpness might need to change, in order to find that balance between frequency of maintenance and the durability of the edge in the particular tasks you give it.

And experimenting with different edge finishes (coarser vs. more polished) can tell you a lot about what the edge really needs to be durably sharp and also an efficient, effortless cutter for the job being done with the knife. So, 'sharp enough' can also be a question of which edge finish - either coarse & toothy, or polished shaving edge - works better for the job. Sometimes 'sharp enough' also means greatly simplifying the sharpening job itself, which might be reduced to using just one stone to get the edge where it works best for you.
 
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If your edge is rolling or chipping, then it's too thin for the given task you're trying to use it for. Your options are a micro bevel, or taking the edge a few degrees higher till you don't get any damage. I don't really think of it as too sharp. It's just not a good match for what you're trying to do with it. I want the cleanest sharpest apex as I can get whether it's an axe, or a kitchen knife.
 
I mean... if all you're interested in is seeing how thinly you can slice a tomato, then I suppose there's no such thing as being too sharp. If you want to whittle wood, then I think it depends more on the steel and the heat treatment.

I sometimes get flak for this, but I tend towards 20 degrees per side, mainly because I prefer softer stainless steel like what you find on a swiss army knife. I like something that's corrosion resistant and easy to sharpen. I already know that I'll be constantly touching up the edge anyway, since staying on top of an edge always makes the most sense regardless of what steel you've got.

I think most people couldn't and wouldn't be able to field sharpen a knife to save a life let alone just for their own convenience, and so that's why they tend towards steels that hold an edge longer. It's really disappointing to see how many people exclusively rely on fancy sharpening equipment and can't do freehand as a result. These are the kind of people using microscopes to look at their edges and yet they don't have any ability at all to actually sharpen a knife by hand. 😞
 
I put different edges on different knifes. It's not just about how the edge holds up but also how it cuts for the task. I'm always experimenting with different edges.
I really don't have much use for a knife with a really highly refined edge.
 
Guy McVer said:
I mean... if all you're interested in is seeing how thinly you can slice a tomato, then I suppose there's no such thing as being too sharp. If you want to whittle wood, then I think it depends more on the steel and the heat treatment.

I sometimes get flak for this, but I tend towards 20 degrees per side, mainly because I prefer softer stainless steel like what you find on a swiss army knife. I like something that's corrosion resistant and easy to sharpen. I already know that I'll be constantly touching up the edge anyway, since staying on top of an edge always makes the most sense regardless of what steel you've got.

I think most people couldn't and wouldn't be able to field sharpen a knife to save a life let alone just for their own convenience, and so that's why they tend towards steels that hold an edge longer. It's really disappointing to see how many people exclusively rely on fancy sharpening equipment and can't do freehand as a result. These are the kind of people using microscopes to look at their edges and yet they don't have any ability at all to actually sharpen a knife by hand. 😞
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Your post helped me narrow in on my confusion a little. If my edge is for example 20 degrees, then no matter how sharp the edge is, it will always be 20 degrees, simply a smaller angle. I haven't notice a big difference in edge retention when I've gone for broke on full size camping knife. But then again, I've always gone to 2k grit until these last few years I've moved up to 0.5 microns (30k-46k). Maybe I would've been better off stopping at 1k grit or even getting a 600 grit stone.

And probably stop being lazy and test this out myself for my knives.
 
There has been all kinds of cut tests done, Joe Calton has done a bunch using an opinel on rope, polished vs toothy.
Just a knife maker in his garage but it's his experience. Pretty sure there is probably a machine out there to do cut tests.

 
NeedItCheaper said:
Your post helped me narrow in on my confusion a little. If my edge is for example 20 degrees, then no matter how sharp the edge is, it will always be 20 degrees, simply a smaller angle.
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I think you probably made a poor word choice at the end, but I believe what you're actually trying to say is that while the angle stays the same as a knife edge gets dull or is sharpened, what changes is how pointy or how rounded it is at the apex (the peak, the tip). This is a major determining factor for how to conceptualize what the level of sharpness is.

That's pretty basic stuff, but yeah. If you really want to go down to that level, then a knife is essentially just a wedge. It's a long and thin wedge, stretched as it is into the third dimension, but nonetheless it remains a simple wedge. Wedges split things, and that's exactly what happens when you cut or slice with a knife. Unsurprisingly, a pointy wedge works better for separating or splitting material than a rounded wedge. But there is a caveat. The rounded wedge is stronger. It's less effective, but it's more stable.

The angle also determines strength and effectiveness. A more acute angle can be more effective at getting a cut started, yet it makes the apex of the edge more fragile, while the opposite is true for a more obtuse angle. And then we throw in the concept of micro-beveling the edge to strengthen an acute angled wedge by putting a more obtuse angle right at the tip.
 
Obsessed with Edges said:
....But I've also known it's a certainty the shaving sharpness isn't going to be durable in most typical uses for a knife and will likely disappear in the first cut or two.
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I agree for the more basic steels. Some of the harder high carbide/high edge stability steels out there not so much. Check out some of the videos from BBB or Michael Christie as an example.
 
chalby said:
I agree for the more basic steels. Some of the harder high carbide/high edge stability steels out there not so much. Check out some of the videos from BBB or Michael Christie as an example.
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I could likely agree with that. There can be truly 'exceptional' exceptions with some higher-grade steels, and occasionally even simpler ones that've been heat-treated very well.

I have an older Case 6265 SAB Folding Hunter from around 1965 or so, which I acquired in well-used condition in their older 'CV' carbon steel (modified 1095). I reset the edges on both blades on sandpaper to a narrower, convexed edge profile. I tested the secondary blade by cutting up a cardboard USPS mailer box into ~1" strips. To my surprise, the edge on that blade actually seemed to shave hair from my arm even better, after I'd finished 'shredding' that box with the blade. That impressed me.

Blades like that are the rare exception, though - especially in simpler steels. But that's why it's good to take it as far as it can go in the initial sharpening, and then see how it behaves after some use. You can then begin to modify the sharpening & maintenance scheme for the knife, to take full advantage of the steel's capabilities.
 
I'll chime in with less details but consistent with my experience. I rarely use my 6000 grit stone. A toothy edge at 1000 grit cuts better than a slicker, more polished edge after the 6000 stone. I have varied pressure, angle, speed of stroke, and just about all variables I can come up with and still cannot stand a more polished edge. My experience, however, does not include the more recent super steels. I am receiving my first in S30V next week. Will be interesting how this may change my experience. with finer grit stones.
 
In standard edge holding tests (CATRA test), the higher the initial sharpness the longer an edge will cut. Edge holding is not a linear relationship to how much material is cut. Since BESS sharpness testing is mostly available to anyone interested enough, I’ll use that as a measure of sharpness.

If initial sharpness is 60, getting to 120 will require cutting a certain amount if material. Going to 200 will take much more material than going from 60 to 100 did. The fuller it gets the more material required to the point of absurdity. I tried to take a cheap Chicago Cutlery knife from shaving sharp to the point it wouldn’t cut paper. I got to 3,000 feet of cardboard and gave up. I could still fold a piece of notebook paper in half l, stand it up, and swing at it and cut it cleanly in two. I could also hold the same paper in one hand and slice it with the knife in the other. Not cleanly, but it would do it.
 
Yes ! I have sharpened scandi to the point it's scalpel sharp .. Scandi edges allow you to go crazy sharp ..
And yes , it makes the edge very fragile , because scandi is already easy to roll , especially with steels not up to the task ( tough enough )
Does the knife need to be scalpel sharp ?
It is up to the individual to make the edge sharp enough for purpose ..

You do what the steel will support !
It's no wonder so many micro bevel scandi ( Cos of the scandi roll ) ..
I own a few scandi edged knives , & ................
I have reverted a few to standard edges , and I have made a few scandi ,,
Some are good and some are ........... bad !
Depending on what quality you hold in regard .
I am not talking about any one knife here as I own several brands of scandi .

A) I like scandi
1. Easy to sharpen / maintain ( Minimal effort )
2. Cut well
3. Can be made scary sharp ( if you want )
4. I would buy more scandi , especially folders if they were priced reasonably .

Cough / cough / cough / ColdSteel ........ ( For budget scandi ) or maybe the Gerber Mansfield ( I really like mine )
 
I am hardly a sharpening expert, and I've just read many in this thread who are way more expert than me. But, what I do sometimes is to get a knife shaving sharp and then strop it on cardboard, leather, or a mousepad. Something which will give a little bit with the goal being to microscopically radius the edge to make it more durable.

I actually have a leather belt charged with compound hanging in my basement to hold the end of and strop on. The "free hanging" belt puts a bigger radius on the edge for tough use things like machetes, etc..
 
davek14 said:
I am hardly a sharpening expert, and I've just read many in this thread who are way more expert than me. But, what I do sometimes is to get a knife shaving sharp and then strop it on cardboard, leather, or a mousepad. Something which will give a little bit with the goal being to microscopically radius the edge to make it more durable.

I actually have a leather belt charged with compound hanging in my basement to hold the end of and strop on. The "free hanging" belt puts a bigger radius on the edge for tough use things like machetes, etc..
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A micro convex , is sweet ! Especially when you get it just so ... ( On scandi )
 
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