Wondering what everyones idea of what is "Practical" sharp?

wackafew said:
I shaved some hair off of a mouse last night that was sleeping in the corner of our porch. He only woke up when he started to shiver. :)
Click to expand...

This was cute lol. Now you owe that little guy a sweater.
MouseSweater.jpgMouseSweater2.jpg

In all seriousness. I'm happy when my knife can shave my arm hair. I'm running out of arm hair though.
 
There seems to be a wide variety of opinions on this matter. Most of 'em will work out pretty well. I guess everybody sets his own standard.
Sonny
 
A practical edge would be one that cuts what you need to cut without undue drama.

I do like hair whittling edges though but they're not very practical.
 
My current standard of sharpness is dried beef ears. I cut them into thirds for my dogs and I can really tell the difference between a freshly sharpened blade and a well-used one. Those things are TOUGH to cut!
 
When I get to the point where I can run the blade just above the skin on my arm and I can feel the blade catching the hair and popping it off.

I'll touch them up to that point once or twice a week, then let the edge ride in between touch ups.
Not that much of a hassle nor does it take much time when your main bevel is sharply set and your just touching up a micro bevel.
 
Last edited:
Printer paper and shaving arm hair are likely good realistic standards for most people...my goal, however....



Ih7Md.jpg
 
HoosierQ said:
Right now, what I am doing for the present, is reprofiling my edges down to about 27.5 degrees inclusive and then putting either a 30 or a 40 degree microbevel on there. The 40 seems a little to obtuse...it does not push cut paper very well, but it does chores well. I am also not seeing a real benefit of edge retention at that angle that I expected either. I am going to stay at 40 for awhile but am considering redoing them to 30 and seeing how that goes.
Click to expand...

I set 40 deg. micro bevels on all my knives with the ultra fine sharpmaker rods and I can whittle hair with every single one of them BEFORE stropping. Maybe youre doing something wrong?
 
Scubie67 said:
Wondering what everyones idea of what is "Practical" sharp?
Click to expand...

I use the "fingernail test".

If I can rest a blade at a 30° or lower angle on my fingernail and it does not slide, it is sharp enough for everyday use.

Among other things, using this test saves hair.
 
knarfeng said:
I use the "fingernail test".

If I can rest a blade at a 30° or lower angle on my fingernail and it does not slide, it is sharp enough for everyday use.

Among other things, using this test saves hair.
Click to expand...

I just get a baggie of hair from the Salon near me. :D
 
elkins45 said:
My current standard of sharpness is dried beef ears. I cut them into thirds for my dogs and I can really tell the difference between a freshly sharpened blade and a well-used one. Those things are TOUGH to cut!
Click to expand...

Those can get stuck in their intestines eh? I had a lab that died because of chewing on beef ear. Just wanted to pass that on, i'd hate for your dog to get injured over a chew toy.

I give my dogs raw beef bones, supervised obviously. They are too big to swallow, cheap, and provide a good amount of chew time.
 
CWL said:
The knives in my pocket, whichever one it may be, has to be able to take 1.4" off of the buttcap of my cigar without wrecking it.
Click to expand...
Me and a few friends were celebrating and I had brought cigars. It felt like a good occasion to use my (then new) small sebenza to cut the cigars, but I wasn't confident that the factory edge wouldn't mess up the cigars, so I used my SAK instead (hair whittling), since I was 100% sure it would work. I then put a new edge on the sebenza.
 
Slicing easily and cleanly through telly paper and arm hair shaving are sharp enough for me. I do like the polished edge so take extra time to get a nice polish with the Lansky Ultra fine and Blue sapphire ceramic hones.

My sharpest once sliced a Higgs boson cleanly...Sheldon won't pay up...cheap bast...
 
I've made 50 degree inclusive edges whittle free hanging hair on many occasions. 40 inclusive is not even close to being too obtuse to take a paper slicing edge.

That threshold is somewhere beyond 60 inclusive, as I've sliced phone book paper cleanly with 60 degree edges. Geometry doesn't really have much of anything to do with slicing paper. It all comes down to how well the apex formed.



HoosierQ said:
Groovy Avatar mkjellgren!

Different knives (I should say knife jobs) have differened requirements. A tough use knife like a kukri really does not need to be super sharp to get its job done...chopping, general mulitary camp chores, and striking an enemy frankly. To sharp (or more accurately too acute) and it will not stand up.

A butcher knife needs to be very sharp. Sushi knife, very sharp. Wood carving knife, also very sharp.

There are also different kinds of sharp. Acute vs obtuse. For all around general purpose use, like a pocket knife or a belt knife, a 40 degree inclusive angle is a good choice. For surgery, scalpels are crazy acute at like 15 degree inclusive...but they don't have to hold that edge...one gets dull, its thrown out.

Knife edge geometry is always a compromise. If an edge is very very good at something, it is likely not going to be nearly so good at something else.

Right now, what I am doing for the present, is reprofiling my edges down to about 27.5 degrees inclusive and then putting either a 30 or a 40 degree microbevel on there. The 40 seems a little to obtuse...it does not push cut paper very well, but it does chores well. I am also not seeing a real benefit of edge retention at that angle that I expected either. I am going to stay at 40 for awhile but am considering redoing them to 30 and seeing how that goes.
Click to expand...
 
I like my blades to slide through whatever I want to cut with ease. I find that if the blade can easily shave my arm hair then it will do whatever job is required. In the kitchen any plain edge blade (excluding butter spreading knives) should be able to slice a tomato, if not I'll grab a coffee cup and strop the knife on the unglazed ceramic on the bottom until the knife feels sharp enough to me.
I don't like to have to saw away with a blunt knife, if it cuts easily then I'm happy. If it struggles to do the job then I need to do some sharpening!
 
Hair shaving is above and beyond "practical" in my opinion. I just like to get it up to that level when sharpening, then let it dull from there.

As far as practicality or what's sharp enough... I generally find my edges stay sharp enough to cut things far beyond the point they no longer shave.
 
I don't have a task oriente test like hair whittling or paper slicing because there is such a wide range of abrasives that will get you there. I tend to pre polish our polish edges. Hair whittling can happen at something like five to ten times the abrasive particle size.
 
I just need my EDC arm hair shaving sharp and I'm happy. This thread has reminded me of how much I need a strop for touch-ups though.
 
You must log in or register to reply here.
Back
Top