Is shaving sharp sharp enough?

timsclips

timsclips

Joined
Nov 27, 2007
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Once a knife gets to the point of shaving sharp, can clean the hair off of your forearms for example, is there a need to try to sharpen further?
 
I don't think so, unless you want to get it to "clean the hair off your face";), in which case you risk getting an edge that will chip very easily.

Best,

Edalb
 
timsclips said:
Once a knife gets to the point of shaving sharp, can clean the hair off of your forearms for example, is there a need to try to sharpen further?
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I'd say it's a matter of what's the most efficient use of your time and effort, and to some extent what kind of cutting you'll be doing.

Many here accept it to be fact that the sharper you get get a blade, the longer it will take to get it too dull for the job you're doing (there's nothing magic in this, it's similar to saying that the faster your car is going when you apply the brakes, the longer it will take to stop.) So say, for example, you can get your knife shaving sharp on a Sharpmaker; it's possible that a bit of stropping is a good investment of time, in terms of time spent sharpening vs. how long the edge lasts. But if it takes you five minutes to strop, and you're going to be cutting a bunch of cardboard, the time spent stropping is wasted.

However some things you might need to cut really benefit from having about as sharp an edge as possible: fine wood work, or cutting leather come to mind. Sometimes the extra time and effort sharpening are worth the result, even if it's taking more of your time.
 
There is some truth to sharper edges lasting longer, but it isnt proportional, an edge twice as sharp isnt going to last twice as long. For example, lets say your edge is 0.01" (just a number, I dont know how thin a shaving edge really is) vs one thats 0.005", the second edge will wear faster being that its much thinner, but you still get some use out of it before it reaches 0.01".

The main concern imo is what you'll be using the knife for, because a very thin edge is more likely to be deformed under stress.
For example, I just reprofiled one of my knives that had a pretty obtuse grind to a much lower angle, not sure what angle exactly but the visible grind line is more than twice as wide. It has a wicked sharp edge on it, but when I use it on very hard wood the edge gets rolled.
 
I sharpen my knives til I can get shaved patch off my arm. Then I am good to go.

Never needed any knife sharper than that.
 
Where is GunMike and his "its amazing what a little skill and OCD will accomplish" signature? I keep my EDC shaving sharp, and once it wont shave anymore, its time for a tune up. I dont need to, but it only takes about 10 minutes a week on the Sharpmaker. After sharpening, it will typically cut a free hanging hair, not just shave my arms. I also find that more polished edges can last longer, depending on the type of cutting. I once tested a Schrade on aluminum cans and cut through the side of a drink can over 120 times and the edge would still shave. My Kershaw Vapor gets a trip to the belt sander with a 220 grit belt and loaded leather belt whenever it sees serious dulling. However, I managed to keep it shaving sharp using a Sharpmaker about once a week, and didnt go back to the sander for about 4 months. The trick is to sharpen at an angle about 5 degrees less per side than the touch up angle. This reduces steel removal to a minimum, and the narrow, higher angle bevel doesnt reduce cutting enough for me to notice.
 
...as opposed to a very large molecule? ;):D

In response to the original post I'd say it's sharp enough whenever you think it is. There are times when I want a knife to be hair-splitting sharp, there are times when I just want it shaving sharp. There are times when I don't even want it to shave (very well) and I would rather it have as course and 'micro-toothed' as can be.


Kinda like asking if 2000fps is fast enough for a bullet. What bullet? What's it's use?
 
There are no absolutes. If your sharpening is a necessary function to prepare a knife for use as a tool then, yes, it is sharp enough when it does the job. If you are sharpening a knife as a hobby then, no, it's rarely sharp enough. :)

I read someone's post about his slicing knife being so sharp that he could merely touch a tomato and the blade would fall thru it. There was once a TV commercial claiming their knives would slice a tomato so thin it (the tomato) would last all week. That's sharp. In comparison, my fine-edge slicing knives require a gentle pull to slice thru a tomato. I can slice several months worth of tomatoes in the time it would take me to strop my knives to "fall-thru" sharpness (if it can actually be done). Since I never use a chef's knife or a hunting knife to shave my face, why bother. My knives are tools; I sharpen them for the job. Tools or hobby?
 
Shaving sharp is my minimum for carry, as on my coarsest stone I get my edges to shave. At DMT Coarse you can get a really nice shaving edge with good microteeth for slicing. For toothier edges that are really sharp Tom Krein is king in my experience with his tree topping, free hanging hair cutting 120 grit edges. My OCD makes me get at least free hanging hair cutting (usually around Spyderco Medium), or most likely hair whittling sharpness (varies from Spyderco Medium to UF depending on the knife and my caffiene level) on my EDC's (I carry more than one), and when they fail to shave I resharpen them. Most of my knives will still cut well enough to do the job at the point I deem them too dull, especially my Krein regrinds, but I have so many different folders it gives me a chance to rotate EDC knives and get in more sharpening time (this is the whole hobby vs. tool debate). For use as a tool, if it still does the job and cuts good enough to complete the task then no, of course your knife doesn't "have" to be shaving sharp as long as it makes the cuts you want.

Most of my Kitchen knives get marathon sharpening sessions up to .05 micron lapping film for great bragging edges that scare people used to a dull Wustof when they use them. Plus, on my Takeda Gyuto, at 8000 grit the 4 degrees per side edge still looks toothy under magnification, so I feel the compulsion to takes it up to .05 microns. At that sharpness level with such thin geometry it guillotines through food and sticks itself into the cutting board on every cut. That is quite a satisfying feeling.

Mike
 
Not for me. Actually, it really is, but I try and get them as sharp (or sharper) than humanly possible.
 
I had one of the guys at work shake his head as he watched me sharpen my knife. I asked if he thought it was crazy what I considered sharp. He said "a little, but what's really crazy is what you consider dull." :D
 
I think it depends on what you are planning on slicing. You going to be sawing vines off the roller of the chipper, or are you going to slice up milk bottles or cardboard? Maybe just open an envelope? As someone alluded, really ultra-sharp blades can be fragile as a consequence of being too thin for the job at hand. Don't believe it? Slice/whittle a few bottle corks with a straight razor. Look at the nicks in the blade. Now try it with your hunting knife. What's the difference?
 
superc, The problem with the straight razor is more its thin grind than whether the apex of the edge is sharp. You would have worse problems with the straight razor blade on the corks if it is dull than if it is sharp. The blade does not have to be much thicker to pass the test. Try it with your thinnest kitchen knife. I think you'll get better results with a kitchen knife after it has been sharpened than before.
 
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