Why so sharp?

If you have to ask, you don't use a really sharp knife, which by your admission, is the case. Sharper edges cut easier, longer, and with more control. Once you practice, it doesn't take more than a few minutes to put a very sharp edge on a knife. On the other hand, dull edges will last forever.
 
intheshaw said:
So im fairly new to the forums here but see that a lot of people are working to get their knives crazy sharp and I ask why.
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Because it's fun to do, it's another part of the hobby, and because we can. It's a bit like the wine lovers who can take a sip of wine and tell the name, the vineyard, and the year of bottling. It's not necessary in order to drink the wine. It's just taking the hobby to another level. But...

There are certain things that cut better with a super sharp knife that has a polished edge. Of course, edge geometry plays a very important part of the edge retaining ability too, but I've found for my kitchen knives, the parer does better when only finished on a fine stone rather than an ultra-fine or stropping, while the Chef's knife and the Santuko perform better when taken to as fine an edge as I can give them, right down to stropping on bare horsehide. All my kitchen knives use a much thinner geometry than my other knives, between 14-18 degrees inclusive. My EDC requires a thicker geometry, somewhere between a kitchen knife and a camp knife to give me a long lasting edge (about 12 degrees per side) that can take abuse. The finish on it, however, is a mirror polished edge that can split hairs, if I had any on my head to split!

As for having an edge 'last a long time,' that seems to be more of an issue with the geometry of the edge rather than the finish. A knife edge used for cutting cardboard will last longer (i.e. cut longer) if the edge is a bit thicker so there is more meat behind it. That edge can still be sharpened just as fine as a good razor blade, but is much stronger and can survive a harder daily grind around the farm/shop/campsite. The edge can take more abuse because there is more heft to it, unlike the thin edge of, say, a double edged razor blade. Both can be equally 'sharp,' but one will last longer than the other.

So I'm wondering if its worth it to go that extra distance and get them crazy sharp or is it just a time if they are constantly used and abused?
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Keep in mind this is a hobby. That's important. If you enjoy the sharpening process, and don't feel any need to rush through it, and appreciate the results of a beautifully polished mirror finish on a very sharp knife, then the answer is most definitely yes! Like a fine old wine to a connoisseur. :thumbup:

If you just want something that cuts, don't bother. Just make your knife sharp enough to satisfy your needs. Walmart's $2 a carton wine gets you just as drunk. It's all in what you enjoy. This is 'hobby' not 'requirement.'


Stitchawl
 
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One practical reason I see for it is the whole idea of wear resistance. If you have a "sharper" edge to begin with it will stay sharper for a longer amount of time. So for example, a factory edge might need to be touched up in a day or so, but an edge that's "scary sharp" could take months or weeks to reach that same level of dullness because it was at a higher level of sharpness.

Other than that, it's purely a hobby kind of thing for me. I like to work with metal and stuff, and I think that the level of scale is kind of extreme craftsmanship when you consider just how tiny the edges we're working with are. So that's always nice for pride's sake.

I think pride is harder to maintain than a really sharp edge though when you think about it. Even if you sharpen off something like 750 grit, you can pop hair, so really getting a pretty razor sharp knife is not that hard, the challenge is just getting it perfect and sharper. Then on the other hand, if you mess up and nick or dent your blade, then all that "perfection" is gone even though a tiny little nick or deformation is not going to effect the performance of the blade over all, and you're left with the dilemma of keeping the rest of that great edge you made for the practicality's sake, or taking the ding out for pride's sake.

So yeah, as much as I like to brag about my edges and take pride in them being really sharp, but when it comes to obsession over actually using them, I usually find myself hesitant to use them for anything that would damage them, but have had people roll over my edge scraping something hard enough times to have gotten over it. Besides, once the edge is damaged, then you get to sharpen it again.
 
There was a series of cutting demos by unit. Correct me if I'm wrong but I had the impression that the knife ground at the lowest angle bevel(sharpest, obviously) was still sharper after a series of hard cuts on tough materials than the higher angled bevels of the other knives before the higher angle bevel knives started their cuts.
 
Ankerson said:
Because we can. :D


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Photos. :)



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Very nice. :thumbup:

Better still is the amount of edge retention you can still get out of that steel at those low angles.

I normally either finish on my fine sharpmaker stones or (if I'm feeling daring) the UF ones. I don't sharpen every day, a touch up once a week or so is decent.
 
Wow some of them blades are nice!
O.K What about a 5mm thick bowie knife?
What would the best angles be for them?
I am having a bit of trouble with a flat grind D-2 steel bowie. It is 5mm thick.
I want a good strong edge.
I am learning to Sharpen free hand but i will go to my Lansky if i have to.
I also have a Spyderco Sharpmaker .
Help please
 
It is entirely personal preference. A Lambo isn't the right vehicle for everyone, neither is a GMC 3500 Dually Diesel.

On the one hand, a knife that is 'sharp enough' will stay that way for quite a while. On the other, a 'really sharp' knife is a completely different animal, and you will most likely sharpen it back up before it gets to 'sharp enough'.

If you don't want to spend the time maintaining a high performance edge, then there will never be a great argument for doing so. If you prefer ease of use and high performance, then you won't settle for a 'sharp enough' edge, no matter how quickly you can get it. Different strokes.

I used to sharpen everything on a blue crock stick, but for the cutting I did then, the edge didn't last long enough to make it worth messing with. Now, I sharpen to an extremely fine edge, and for the cutting I do, it lasts a long time.

Use what you need, high performance in any direction will result in compromises in others, so choose wisely.
 
That sounds like good logic.
I just put a 30deg per side back bevel on it with the Lansky. It is just sharp enough to shave leg hairs.
I give that a go on some wood tomoro.
 
j man said:
That sounds like good logic.
I just put a 30deg per side back bevel on it with the Lansky. It is just sharp enough to shave leg hairs.
I give that a go on some wood tomoro.
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Do you really mean 30 degrees per side? 60 degrees inclusive? Axes don't usually get that thick!!! :eek:


Stitchawl
 
(sorry, can't go into detail, YET)

i saw a man hit another man in the upper arm, near the deltoid, with a cheap sword. he used a two handed grip and looked like he was swinging for a home run. the guy on the receiving end, who actually went to jail, had a small scratch that required a BANDAID.

now, in all fairness, the BG was wearing a long sleeve shirt and the GG used a more of a hack, he didn't draw through the cut the way i would've. however, it still made me think - had he wacked him that hard with one of my blades, there'd've been a pretty big mess. btw - i felt the edge on the sword, it wasn't exactly dull, just wasn't the "crazy sharp" we all seem to prefer and now i feel i have a good reason to prefer them.
 
stitchawl said:
Do you really mean 30 degrees per side? 60 degrees inclusive? Axes don't usually get that thick!!! :eek:


Stitchawl
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i use 30* per side, alot. in fact, 25* per side is as acute as i go.

ETA - unless the measurements on the Lansky are referring to inclusive.
 
What changed my mind about highly polished razor like edges was when I tried to cut some 1/2" manila rope. The hairs on my arm would jump off by them selves at just the appearance of the knife ;), but it just slid off the rope. I made a few passes on my crock stick and it went through the rope like it wasn't there. My only explanation is that the edge need some "tooth" to bite into the rope.

Your results may very.
 
My take on it is this....sharpening a knife is an art form......thus, guys what do it are quite passionate about it.
So "sharp" becomes relative to each of us......most of us are trying to learn and improve, and the good news is, here at BF, we are surrounded by those willing to teach and share their expertise.

I believe I need a tissue........:D
 
UffDa said:
What changed my mind about highly polished razor like edges was when I tried to cut some 1/2" manila rope. The hairs on my arm would jump off by them selves at just the appearance of the knife ;), but it just slid off the rope. I made a few passes on my crock stick and it went through the rope like it wasn't there. My only explanation is that the edge need some "tooth" to bite into the rope.
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Could this be why God created half serrated blades??
 
zignal_zero said:
i use 30* per side, alot. in fact, 25* per side is as acute as i go.

ETA - unless the measurements on the Lansky are referring to inclusive.
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LOL! They are!! :p 30 degrees per side would look like a paperback book spread open face down on a table with the spine raised up about 2".

Stitchawl
 
intheshaw said:
So im fairly new to the forums here but see that a lot of people are working to get their knives crazy sharp and I ask why. The knives I have are used everyday and are usually beaten up by daily tasks. I have a DMT c/f duofold that gets them sharp in a short amount of time. Ive never have a knife that could pop the hairs off my arms but they can definately perform whatever task that I throw at them. So I'm wondering if its worth it to go that extra distance and get them crazy sharp or is it just a time if they are constantly used and abused?
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There are some tasks you can not do without very sharp knife. For exaample I cut my skin right on top of the splinter without drawing blood so splinter fall out easy. Good edge doe not require too much pressure to cut and so I found a lot of thing I can do now. Another sample - I use my EDC to cut stake over lunch. Becasue I can do this without hitting plate by edge, in the air - no need to pressure. Same with plastic bags - I hold it in one hand and swipe with one light move along the side with another - much less time to spend. Many thin you can do with one simple cut - will it be bread or piece of tooling leather...

I also noticed that all my big cuts I did to myself was done using dull knife, because instead of sharpen it I rather throw some power and lose control and accuracy. I cut myself time to time with sharp knives but it is usually pretty minor cuts.

Another reason - I do not see point to sharpen knife duller then I could, if I spend same effort (and most of it is removing burr) why not to do same on honing leather with Green Rouge instead of using same stone? I is not really clear what will take less time. So for me make it duller will be additional effort so I simple use same procedure for everything.

Thanks, Vassili.
 
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