How sharp is sharp enough?

Sonnydaze

Sonnydaze

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I have several new folders that I will gift to family members.
Spyderco edges are usually very good, but some other manufacturers produce a "factory edge" which is not very sharp.
I have an Edge Pro and am just getting started with it. I want to produce good edges, perhaps even mirror edges, but I realize that you still need a good "toothy" edge in order to cut the skin of a tomato.
I have a nice selection of stones and automotive sand-paper and a Spyderco 306mF stone.
What suggestions do you have for stone grits and where to stop?
thanks,
Sonnydaze
 
I usually keep my user knives and kitchen knives around 320 grit. Right where it begans to shave arm hair and still has some tooth. DM
 
From maintaining wife's kitchen knife, a simple Vic paring blade, she's happiest if it's finished on 1000 grit and strop on newspaper.

I have very limited tools to sharpen ;) but usually if it's brought to 1500 grit sandpaper + compound strop (MAAS polish), she says it doesn't bite enough.
 
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Put the same edge on them that you'd put on if they were for your use. If you're satisfied that they'd work for you, then they'll work for the people you're giving them to.
 
Tooth is only required when slicing tomatos. High polish is best when dicing or chopping. I usually stop at a 4000 waterstone or Spyderco fine.
 
singularity35 said:
It's never sharp enough...
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This. :D

While toothy edges work well, once you get a polished edge past a certain point, it will zip through tomatoes with almost no resistance also. Doesn't do as good on rope, though. Try a bunch of different finishes, see what you like.
 
I usually sharpen to 1600 grit and then stop stropping at 3.5 microns. For when it cuts this...its sharp enough. I usually test in a sheet of paper...phone book or printer. If it slices that then I know I'm good to go.
 
A toothy edge makes slicing a tomato easier for most people, and it can be applied with much less work. BUT, a toothy edge isn't necessary to slice a tomato. If the apex of the edge is well-executed and pure, and the geometry (shape & thickness) of the edge & blade is right, a highly polished edge can do just as well. At that level, it becomes more about push-cutting, and the 'teeth' on the edge are less necessary. But, the apex does have to be good, for that to work. 'Teeth' are more helpful on edges with less-than-ideal geometry or less-than-complete apex; most 'normal' people's kitchen knives are a testament to that, with roughly-finished & heavily-burred edges on (sometimes) truly hideous grinds. They'll still cut tomatos, so long as there are enough 'teeth' to initiate a cut. That's also what makes carbide scraper pull-through sharpeners 'work' for some people. Leaves a very ragged edge that does cut, but not very cleanly, and not for very long. They stop working when the teeth erode away, and the bad edge geometry is all that's left.

One of my favorite tests is cutting tomatos or grapes with my just-sharpened edges. I've regularly been able to slice both cleanly at edge finishes of 2000+ grit (wet/dry sandpaper), which are fairly highly-polished, and aren't particularly 'toothy'. In fact, without a microscope, I wouldn't likely be able to see or feel any teeth at all, on these edges.

More often than not, I test my edges by slicing phone book paper, at a minimum. If an edge slices cleanly & repeatedly through a single sheet, along the full length of the cutting edge (ricasso to tip), with no snags or slips, that's pretty satisfactory for me. But, it won't stop me from trying to take it further. I just can't seem to put it down... :D
 
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When you slice tomatos and grapes, are you holding them, or just letting them rest on a cutting board?
 
me2 said:
When you slice tomatos and grapes, are you holding them, or just letting them rest on a cutting board?
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Now you're making me go back to the grocery store! I'll give this a shot both ways, never thought of this...
 
You can drop vedge on a blade and itll slice it in half if its slicing sharp.
 
Mine are sharp enough when they will cut arm hair without scraping my arm, and I can run a "Q" tip down the edge without any snags. I can usually achieve this with my paper wheels alone, and no need for a strop. I sometimes use a strop for a further edge polish if I want to produce an eye pleasing look for someone. Doesn't seem to add to the sharpness, but just the visual effects. Sharp enough is when it will do the job you need it to do without a lot of extra effort. After all, it is a tool, not unlike a hammer to drive a nail. If the hammer drives a nail efficiently and without much effort, it is the right hammer for the job. So, if your knife cuts what you want without a lot of effort, then it is "sharp enough". YMMV

Omar
:rolleyes:
 
its sharp enough when you can cut things just by pointing the knife at it (from no less then a distance of 20 feet)
 
I like the phone book paper test, if it can slice the length of the blade without snagging then I am finished
 
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