At what level of sharpness do you stop sharpening?

M

MichaelMyers

Joined
Dec 10, 2015
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235
For me i stop and call it a day when it can slice newsprint cleanly. What is the acceptable standard for your use?

slicing cardboard
printer paper
Magazine paper
shaving arm hair
newsprint
hair whittling
tree topping hair
slicing tissue paper
 
I used to call it good with the thumbnail test. Since joining bf and learning so much on these forums now I stop sharpening when I can cleanly slice phone book paper across the grain. I'm still learning and need more practice to whittle hair reliably.
 
Hand sharpening on stones took a little effort and concentration but now that I have the Edge Pro it is brainlessly easy . . .
In either case I usually sharpen until my arm hair starts to abandon ship and jump off my arm while the blade is still on the stone and or in the jig. That's how I know the edge is hair whittling sharp or as I like to say shaves curls off a single hair while it is still in my arm. They hate that . . . they would rather I just take em out quick and clean with no suffering.

Does it stay that sharp after the first big cardboard box or large wire tie ?
Well . . .
 
MichaelMyers said:
For me i stop and call it a day when it can slice newsprint cleanly. What is the acceptable standard for your use?

slicing cardboard
printer paper
Magazine paper
shaving arm hair
newsprint
hair whittling
tree topping hair
slicing tissue paper
Click to expand...


That is asking the wrong question. Sharpness is not refinement. You can cleanly slice newsprint coming off of a very, very coarse stone if you have a truly burr-free and fully-appexed edge. You can even get to whittling hair with a relatively coarse edge if you've done a good job. The question I think you want to ask is "At what level of refinement do you stop sharpening?" Because with regard to sharpness, you should only stop sharpening once you've fully sharpened, unless you are in an emergency or just need to do a very quick and dirty job to get some rope cut, for example.

As for what level of refinement I stop sharpening, for a working edge, it could be as coarse as 400 grit or so (stropped thereafter). For a good kitchen knife, I wouldn't go above 2k. That said, I am not a sushi chef, and I don't usually sharpen very high-end kitchen knives; maybe they could go to 6k or higher. And if you are finishing a straight razor to shave with (which I do not do), I understand that honemeisters like to go far, far above that -- as high as 10k or more so that the edge is like glass to keep facial irritation to a minimum. That said, you will see folks here write that they don't go that high with their razors.

Slicing tissue paper isn't that hard, but push-cutting tissue paper is very hard. I have never tried to push-cut tissue paper, not even as a challenge. It doesn't achieve anything for my purposes, but I do recognize that it requires a very refined and very sharp edge.
 
I thought it was agreed (something I read in one of the stickies) that knives do get sharper as the edge is refined.

As for the OP's question, you left phone-book paper off your list. I consider that harder to slice than newspaper.

I am generally satisfied with slice-cutting phone-book paper with the grain.
 
For kitchen knives, I no longer test. A few passes on my Sharpmaker's medium rods (~1000grit) and I 'know' it's more than sharp enough for the tasks at hand.

For EDC knives, I use the 'phonebook paper' test. Not as much for the 'ability' to slice it but for how 'smoothly' it slices. At this level, it's more than sharp enough for my needs.
 
TravisH said:
For kitchen knives, I no longer test. A few passes on my Sharpmaker's medium rods (~1000grit) and I 'know' it's more than sharp enough for the tasks at hand.

For EDC knives, I use the 'phonebook paper' test. Not as much for the 'ability' to slice it but for how 'smoothly' it slices. At this level, it's more than sharp enough for my needs.
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+1

That's my universal test as well. The ease or smoothness with which it slices phonebook paper will tell a lot about the condition of the edge, such as indicating presence of burrs, nicks or rolled edge, edge not fully apexed, edge geometry too wide, etc. A very clean & crisp edge at a nice, thin geometry will zip effortlessly thru it. Even the sound of the slice will be different, depending on edge finish and geometry. Coarser finish sounds like a 'zipper', more polished becomes whisper-quiet. Wider edge angles with hard V-bevelled shoulders will be noisy, sounding almost like ripping/tearing; convexed & polished is scary-slick and quiet.

I do this test with ALL my knives, including kitchen knives as well, and it has never deceived about the condition of my edges.


David
 
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Personally, I stop refining my knife edge after a 4K Shapton Glass Stone on my Edge Pro Apex. It's a true mirror edge at this point, then strop with a one micron (roughly 14,000 grit) diamond paste for several minutes. Is this overkill for most, if not all EDC cutting tasks? Yes. But after a certain point it's no longer about how sharp the blade is anymore. It's more personal enjoyment of the task itself.

The edges themselves I typically test out on a piece of phone book paper (which more or less offers little to no resistance to the knife).
 
On my fixed blades I have been stopping after very light passes on KME 300 diamonds, then debur and a few strokes on strop with Stropman black or Flexcut Gold. I can shave arm hair and cut catalog paper with this refined but still toothy edge.

On my EDC folder, I sop at the medium Sharpmaker rods and can easily slice phonebook paper.
 
Yea, definitely phone book paper on edc. On my parlor trick knives I try to get at LEAST a HHT3 or higher. On edc, I usually stop at 600 and strop about 10 to 15 passes on either a stropman white or a CBN 4m paste
 
My normal test is the thin shiny advertising pages in our Sunday newspaper. This is sharper than what I normally need for my typical use but it isn't hard to get there.
 
I want my edges to be able to cleanly cut phone book paper and shave are hair. I just sharpener my large sebenza yesterday and stopped at the 600 grit stone on the wicked edge then stropped. Plenty sharp edge.
 
I like to be able to pull my edge through my arm hair and if it will tree top I'll quit.
 
I sharpen on the fine India until the blade will cut newsprint across the grain cleanly. I sometimes take it to this level on a more coarse SiC stone. This gives a good utility edge. DM
 
Phone book paper for me as well. If I can slice cleanly and easily through the paper at all angles, my edge will be capable of making hair pop off my arm. Plenty sharp for me.
 
I too have a bald arm. [emoji16] But don't use it for testing as much as showing off. And for me, it's not just taking off hair because a lot of somewhat dull knives can still do that. It has to leave a complete bald spot in one swipe with little to no pressure applied. That still puts a smile on my face.

Also use phonebook/catalog paper. Testing with both slicing cuts and push cuts all down the blade to make sure I didn't miss a spot. And it's not just the ability to cut, but the cleanness of the paper edge and also the sound. A quiet "swoosh" is good, a tearing sound during cut is bad. The sound is more dramatic on copy paper, so a swoosh is absolutely necessary for that paper.

And the level (assuming grit)? Anywhere from 300 diamond to 1.5 micron cbn strop polish. Depending on the knife.
 
I used to like newsprint, but I don't get the newspaper so my supply ran out quickly :o The only thing I consistently have is myself, so I typically test by cutting into the pads of my fingers.

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I like to feel the bite with coarser edges, but with refined edges I prefer to see the cut without being able to feel any bite.
 
I like catches beard hair sharp (so, can feel it pulling individual hairs hanging from my chin) no matter the finish, but usually finish at 600 diamond or 1000 ceramic depending on use then strop on hard backed leather with Herbs Yellowstone for a few swipes.
 
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