Testing the Edge

[jerryd6818]

Pad of thumb.

Same here.

[Colonel26]

Pad of thumb. I have very thin skin and I can tell if it is sharp enough for me to smile, very quickly this way. On a related note, I am not very good at achieving this sharpness.
On an unrelated note, it seems to me that knives lose sharpness to a degree, just sitting. Am I nuts?

I’ve noticed some of my knives do seem to lose sharpness spring around and some don’t seem to. I have no idea why but I have noticed that.

[jerryd6818]

I’ve noticed some of my knives do seem to lose sharpness spring around and some don’t seem to. I have no idea why but I have noticed that.

That's because them boys are sneakin' 'em and trying to cut barbwire with 'em.

[Colonel26]

I’ve noticed some of my knives do seem to lose sharpness spring around and some don’t seem to. I have no idea why but I have noticed that.

That's because them boys are sneakin' 'em and trying to cut barbwire with 'em.

Hmmmm. I do see them ogling my edc Knives occasionally. You might not be far off!

[kootenay joe]

I recall a thread in BF years ago in which many people posted that their knives did loose sharpness over time when in storage. Some were people who claimed to be good at sharpening and then knew the level of sharpness that they brought the edges to. Then after a year or two, this level of sharpness was no longer present.
A few metallurgists discussed the edge at the molecular level but could not account for the observed dulling.
When doing 'slice the hanging paper' test, how far from your pinch grip on the paper do you slice ? Someone has said 1". I try at about 3" on newsprint.
kj

[FRJ]

After sharpening I push the edge of the blade into my thumb nail, on the flat, thoughtfully.
Blade at an angle. If it is sharp it will catch immediately.
I try this at the tang and several places up the blade to the tip. I try the other side. Same method.
If it slides I go back to the stone until I get the results I want. A sharp edge.
I can't tell you the last time I shaved hair on my arm. I'm not interested in that.
I tried to cut paper awhile back after sharpening. I was surprised it didn't cut it very well. I don't care.
I put my wonderful knife in my pocket and moved on.

I think blade edges will loose a fine cutting edge in storage. Just noticeably less sharp. I remembering this happening to me. Once.
It probably has happened without my noticing it. Of course I have no explanation for it.

Great thread. It's nice to see sharpening discussed.

[1967redrider]

I cut a ripe tomato. If it cuts easily it's sharp. If it doesn't, resharpen.

[FRJ]

There ya' go. Tomatoes are a good test.

[StrawHat]

I cut a ripe tomato. If it cuts easily it's sharp. If it doesn't, resharpen.

I have done that when sharpening at Farmers’ Markets. Sometimes with a pepper. Except for the waste of food, a great visual test for customers to witness.

Kevin

[Mumbleypeg]

Cutting a tomato is a lot like slicing bread. A "toothy" edge works better than a shaving edge. Same for cutting steak.

Ken

[edge213]

Cutting a tomato is a lot like slicing bread. A "toothy" edge works better than a shaving edge. Same for cutting steak.

Ken

What he said

[Colonel26]

Cutting a tomato is a lot like slicing bread. A "toothy" edge works better than a shaving edge. Same for cutting steak.

Ken

I’ll add my amen there too. I’m not a fan of super highly polished edges on a pocket knife. Those belong on my straight razor.

[tongueriver]

Me three.

[BatJak]

In my youth I thought I had to test the edge every time.
Filet a paper towel or cut phone book paper...
But I've been hand sharpening so long now that I just check for a wire edge and strop.
I will thumb the edge a bit and that tells me everything I need to know.

[KnifeSlinger#81]

I like phonebook paper. If your edge can cleanly slice it (not saw it) they you have a pretty good edge. It also tells you if you have any small dull spots and saves you from having silly looking bald spots on your arm all the time.

[cudgee]

In my youth I thought I had to test the edge every time.
Filet a paper towel or cut phone book paper...
But I've been hand sharpening so long now that I just check for a wire edge and strop.
I will thumb the edge a bit and that tells me everything I need to know.

[EeDeCe]

After sharpening every knife in the house, the arm hair thing wasn't feasible and started to look weird.
Paper test, a push test in different parts of the knife as opposed to a slice. Just a straight on push into the paper.
Also, I've lately been trying my hand at wood carving and have used wine corks to practice on. Now I find those, either real or synthetic, to be a pretty good way to compare sharpness.

[tongueriver]

quote: "I will thumb the edge a bit and that tells me everything I need to know."

Yep.

[Lansky1]

In my youth I thought I had to test the edge every time.
Filet a paper towel or cut phone book paper...
But I've been hand sharpening so long now that I just check for a wire edge and strop.
I will thumb the edge a bit and that tells me everything I need to know.

THis is what I do as well. I've learned to look very closely at the edge (practically studying it) - I can now see tiny flat spots or other issues with inconsistently sharpened bevels - to me, getting both bevels perfect all the way down to the edge with the Lansky rig under close inspection, then a feel for (lack of) a burr ... always comes up with "close enough" to me, as I know it will cut if it passes that test

[AR Norby]

I use cash register receipts. If it will cut those cleanly, i'm good.

[thankgod4rkids]

At home I usually use phone book paper for the initial test but my favorite way to test sharpness is to cut some shrink wrap while it's tightly wrapped around a pallet. We have hundreds of shrink wrapped pallets at my workplace on any given day.

Once I get the blade sharpened to my satisfaction I'll take the knife to work with me and do a final test on some shrink wrap. The shrink wrap is delicate and it responds well to any imperfections that I might have missed along the edge. Fortunately, I rarely need to do any follow up honing but I use the final shrink wrap test to confirm that.

This made me laugh! It is also my method. I test on paper at home then take it to work. The shrink wrap will find any imperfections in a hurry.
Bill

[Working Edge]

I use my thumb for edge testing, followed by shaving of arm hair.
Sometimes I use the number of stitches as an indication of sharpness after inadvertently hooking my thumb over the edge while wiping down a freshly sharpened edge.
Just kidding about the stitches, but I do indeed use a lot of band-aids....!

[Working Edge]

I use my thumb for edge testing, followed by shaving of arm hair.
Sometimes I use the number of stitches as an indication of sharpness after inadvertently hooking my thumb over the edge while wiping down a freshly sharpened edge.
Just kidding about the stitches, but I do indeed use a lot of band-aids....!

[dlr110]

I use my thumb for edge testing, followed by shaving of arm hair.
Sometimes I use the number of stitches as an indication of sharpness after inadvertently hooking my thumb over the edge while wiping down a freshly sharpened edge.
Just kidding about the stitches, but I do indeed use a lot of band-aids....!

You're not the only one on band-aids sir. Right now I have one on my right thumb with a slice on the outside edge, the blade was sharp. On my left thumb is one not from a blade, but from a belt sander when I was shaping a knife handle.

[Dinadan]

I use my thumb for edge testing, followed by shaving of arm hair.
Sometimes I use the number of stitches as an indication of sharpness after inadvertently hooking my thumb over the edge while wiping down a freshly sharpened edge.
Just kidding about the stitches, but I do indeed use a lot of band-aids....!

When I sharpen kitchen knives I use a paper towel to clean the sharpening stone residue off the edge. The slightest bit of inattention and my thumb or finger needs band-aids. That is not my preferred method of checking sharpness, but it does work! I do not normally try to check the edge after sharpening. The first tomato or plum will be a test.