How sharp is sharp enough?

NixKustoms

NixKustoms

Sheath and Knife Maker
Joined
Dec 30, 2010
Messages
5,883
I've been trying to hone my sharpening skills (pun intended), but can't seem to get my knives scary sharp I can only get them sharp enough to shave my arm though.

So really how sharp is sharp enough for a working blade? How sharp to you keep your blades?


(I'm asking here because all I'm carrying now is Beckers :D )
 
I'm horrible at sharpening. Then I got a Spyderco Sharpmaker. I was amazed at how sharp I can get a knife now. It is silly, but I consider a knife really sharp for my taste if it can shave arm hair with ease, and sharp enough if it can slice paper. Because, you know... you never know when paper with arm hair is just going to jump out of nowhere and attack you. :jerkit:
 
Shaving is sharp. I see a lot of folks on here working these edges up to crazy levels. I beat on my knives. Spending 6-8 hours getting a perfect mirror edge on a blade would be a waste, as I would just knock it down the next day.

Much like I don't use my knife as a screwdriver / prybar / etc. I also don't try and use it as a scalpel. I can buy a box of razor blades for a dollar or two.

I do have some really sharp blades - I use a Mora 120 for carving and keep a really shallow, sharp edge on it. I also have some carbon chef's knives that are really sharp, but I only use them for slicing and on a wooden board. They don't ever really get dull.

Most of the time, if it will shave arm hair easily I call it done.
 
If it does everything you require of your knife with ease, it's sharp enough. I use a page out of a phone book to test an edge I'm working on. I grab it by a corner, and if it'll cut clean out to about half way across the page, that's when I'm done. It's safer to use a sharp blade
 
I agree that 'easily' shaving you're arm hair is sharp enough for a working blade, and it will still hold a wicked edge...

Although I have both the spyderco sharp maker (works perfect for me) and the dmt aligner I recently purchased a strop from the knife connection and have been very pleased with the results! I got both my EsKaBar and HEST wicked sharp. There are plenty of vids online and great advice from all these great peeps online.

Works great for me.YMMV

I'm going to convex my BK2 this weekend.....if time permits ;)
 
a working edge is sharp enough to cut what you need to cut and keep the edge without rolling. if you take an edge too fine, its just like a wire edge. i can put an edge on a knife with 80 grit and make it shave hair and cut for a long time if it is a good knife.

here is how sharp i get my knives. the one in this vid is a half convex chisel grind. the vid is dark and the paper gave me problems but you can see how sharp it is. http://knifetests.com/kII.html
 
Ban makes the sharpest knives I have seen yet. Once you habe a "BANNED" knife it can filet a strand of hair.

Check out "stupid sharp knives" on this forum.
 
paperairplane said:
Shaving is sharp. I see a lot of folks on here working these edges up to crazy levels. I beat on my knives. Spending 6-8 hours getting a perfect mirror edge on a blade would be a waste, as I would just knock it down the next day.
Click to expand...

The Sharpmaker gets my knives from dull to shaving sharp in about 10 minutes. I agree that spending too long is a waste of time, but if I recall my old-timer wisdom correctly, you are more likely to injure yourself with a dull blade than a sharp one.
 
Murray Carter has 2 good videos on sharpening techniques. He evaluates an edge using his "three finger test" and it really is the best way to determine what sharp is. The technique is to place the thumb on the back of the blade and three fngers on the edge, with light pressure, move the fingers along the primary bevel. A sharp knife will gently grab the fingers from movement, one that is not so sharp will let them slide along. It is a good technique and it will challenge a persons sharpening skills.
 
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How sharp and how long does it take are two questions without answer.

How sharp and how long will depend mainly on skill and partly on tools.

Shaving sharp comes in many flavors, I for example can have a hair shaving and paper slicing edge from a 120 grit stone where many struggle getting that sharpness at 1k grit. So basically from the very start to the end of my sharpening progression a edge will shave hair.

Its not so much about what the edge will cut but how well the bevel was constructed. How well each abrasive was used and if the resulting edge reflects that.
 
I think "sharp enough" for me changes from one thing to the next. I like my EDC carry knives that I use for everyday tasks to be pretty sharp; hair-shaving to hair-whittling level. I think an edge like this passes through material effortlessly, and if it's not something that I'm putting a lot of work into from the knife then I like to keep it really refined since I don't have to worry as much about edge retention.

For some knives though, I'll usually just raise a burr on each side of the knife and call that good enough. That's usually good enough to cut paper, but I don't really test a lot of the time; just a raise a burr and move on. This is for knives that I use a lot, and hard, like kitchen knives, scrapers, beaters, etc. Then there's other special instances, like where a friend wanted me to sharpen the knife he uses for cutting up insulation.

If I'm just trying to make the absolute sharpest edge that I can I usually want it to be able to whittle hair, but I'm always trying to get things sharper.
 
i use a round fine grit diamond machinists rod, and a diamond impregnated rubber machinists strop, and i can take my zt0350 from beat to shave my face sharp in about 10-15min. but my standard maitaince is 2 passes on each side of the edge with the strop each day i use the knife
 
I am happy to sharpen my knives on a medium Japanese water stone and finish them off on Cardboard and or paper.
They shave hair but not as well as my 4 blade Gillette razor.
:-)
 
How sharp is sharp enough?

Sharp enough that when you wave the blade around, you can hear the air whimper in pain.
 
it's sharp enough if it does the job without interfering with the work.

once it slows down and/or stops and/or gets enough dirt, chips, or whatever, it gets a cleaning and sharpening (or sold ;>)... otherwise, i don't worry about it.
 
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